Initial commit

2024-11-24 06:49:04 +03:00 · 2019-11-18 18:18:28 -08:00 · 2019-11-18 18:18:28 -08:00 · 9ba375c063
commit 9ba375c063
parent 615c2bc21d
388 changed files with 50843 additions and 61 deletions
--- a/.appveyor.yml
+++ b/.appveyor.yml
@ -0,0 +1,19 @@
+environment:
+  matrix:
+    - nodejs_version: "8.16.0"
+      FLAKINESS_DASHBOARD_NAME: Appveyor Chromium (Win + node8)
+  FLAKINESS_DASHBOARD_PASSWORD:
+    secure: g66jP+j6C+hkXLutBV9fdxB5fRJgcQQzy93SgQzXUmcCl/RjkJwnzyHvX0xfCVnv
+
+build: off
+
+install:
+  - ps: $env:FLAKINESS_DASHBOARD_BUILD_URL="https://ci.appveyor.com/project/aslushnikov/playwright/builds/$env:APPVEYOR_BUILD_ID/job/$env:APPVEYOR_JOB_ID"
+  - ps: Install-Product node $env:nodejs_version
+  - npm install
+  - if "%nodejs_version%" == "8.16.0" (
+      npm run lint &&
+      npm run coverage  &&
+      npm run test-doclint &&
+      npm run test-types
+    )
--- a/.ci/node10/Dockerfile.linux
+++ b/.ci/node10/Dockerfile.linux
@ -0,0 +1,17 @@
+FROM node:10
+
+RUN apt-get update && \
+    apt-get -y install xvfb gconf-service libasound2 libatk1.0-0 libc6 libcairo2 libcups2 \
+      libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 \
+      libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 \
+      libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 \
+      libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils wget && \
+    rm -rf /var/lib/apt/lists/*
+
+# Add user so we don't need --no-sandbox.
+RUN groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \
+    && mkdir -p /home/pptruser/Downloads \
+    && chown -R pptruser:pptruser /home/pptruser
+
+# Run everything after as non-privileged user.
+USER pptruser
--- a/.ci/node12/Dockerfile.linux
+++ b/.ci/node12/Dockerfile.linux
@ -0,0 +1,17 @@
+FROM node:12
+
+RUN apt-get update && \
+    apt-get -y install xvfb gconf-service libasound2 libatk1.0-0 libc6 libcairo2 libcups2 \
+      libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 \
+      libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 \
+      libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 \
+      libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils wget && \
+    rm -rf /var/lib/apt/lists/*
+
+# Add user so we don't need --no-sandbox.
+RUN groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \
+    && mkdir -p /home/pptruser/Downloads \
+    && chown -R pptruser:pptruser /home/pptruser
+
+# Run everything after as non-privileged user.
+USER pptruser
--- a/.ci/node8/Dockerfile.linux
+++ b/.ci/node8/Dockerfile.linux
@ -0,0 +1,17 @@
+FROM node:8.11.3
+
+RUN apt-get update && \
+    apt-get -y install xvfb gconf-service libasound2 libatk1.0-0 libc6 libcairo2 libcups2 \
+      libdbus-1-3 libexpat1 libfontconfig1 libgcc1 libgconf-2-4 libgdk-pixbuf2.0-0 libglib2.0-0 \
+      libgtk-3-0 libnspr4 libpango-1.0-0 libpangocairo-1.0-0 libstdc++6 libx11-6 libx11-xcb1 libxcb1 \
+      libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 libxss1 \
+      libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release xdg-utils wget && \
+    rm -rf /var/lib/apt/lists/*
+
+# Add user so we don't need --no-sandbox.
+RUN groupadd -r pptruser && useradd -r -g pptruser -G audio,video pptruser \
+    && mkdir -p /home/pptruser/Downloads \
+    && chown -R pptruser:pptruser /home/pptruser
+
+# Run everything after as non-privileged user.
+USER pptruser
--- a/.cirrus.yml
+++ b/.cirrus.yml
@ -0,0 +1,47 @@
+env:
+  DISPLAY: :99.0
+  FLAKINESS_DASHBOARD_PASSWORD: ENCRYPTED[b3e207db5d153b543f219d3c3b9123d8321834b783b9e45ac7d380e026ab3a56398bde51b521ac5859e7e45cb95d0992]
+  FLAKINESS_DASHBOARD_NAME: Cirrus ${CIRRUS_TASK_NAME}
+  FLAKINESS_DASHBOARD_BUILD_URL: https://cirrus-ci.com/task/${CIRRUS_TASK_ID}
+
+task:
+  matrix:
+    - name: Chromium (node8 + linux)
+      container:
+        dockerfile: .ci/node8/Dockerfile.linux
+    - name: Chromium (node10 + linux)
+      container:
+        dockerfile: .ci/node10/Dockerfile.linux
+    - name: Chromium (node12 + linux)
+      container:
+        dockerfile: .ci/node12/Dockerfile.linux
+  xvfb_start_background_script: Xvfb :99 -ac -screen 0 1024x768x24
+  install_script: npm install --unsafe-perm
+  lint_script: npm run lint
+  coverage_script: npm run coverage
+  test_doclint_script: npm run test-doclint
+  test_types_script: npm run test-types
+
+task:
+  matrix:
+    - name: Firefox (node8 + linux)
+      container:
+        dockerfile: .ci/node8/Dockerfile.linux
+      xvfb_start_background_script: Xvfb :99 -ac -screen 0 1024x768x24
+  install_script: npm install --unsafe-perm
+  test_script: npm run funit
+
+task:
+  osx_instance:
+    image: high-sierra-base
+  name: Chromium (node8 + macOS)
+  env:
+    HOMEBREW_NO_AUTO_UPDATE: 1
+  node_install_script:
+    - brew install node@8
+    - brew link --force node@8
+  install_script: npm install --unsafe-perm
+  lint_script: npm run lint
+  coverage_script: npm run coverage
+  test_doclint_script: npm run test-doclint
+  test_types_script: npm run test-types
--- a/.editorconfig
+++ b/.editorconfig
@ -0,0 +1,9 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
--- a/.eslintignore
+++ b/.eslintignore
@ -0,0 +1,12 @@
+test/assets/modernizr.js
+third_party/*
+utils/browser/playwright-web.js
+utils/doclint/check_public_api/test/
+utils/testrunner/examples/
+node6/*
+node6-test/*
+node6-testrunner/*
+lib/
+*.js
+src/chromium/protocol.d.ts
+src/webkit/protocol.d.ts
--- a/.eslintrc.js
+++ b/.eslintrc.js
@ -0,0 +1,107 @@
+module.exports = {
+    parser: '@typescript-eslint/parser',
+    plugins: ['@typescript-eslint'],
+    parserOptions: {
+      project: './tsconfig.json',
+      ecmaVersion: 9,
+      sourceType: 'module',
+    },
+
+    /**
+     * ESLint rules
+     *
+     * All available rules: http://eslint.org/docs/rules/
+     *
+     * Rules take the following form:
+     *   "rule-name", [severity, { opts }]
+     * Severity: 2 == error, 1 == warning, 0 == off.
+     */
+    "rules": {
+        '@typescript-eslint/no-unused-vars': [2, {args: 'none'}],
+        /**
+         * Enforced rules
+         */
+        // syntax preferences
+        "quotes": [2, "single", {
+            "avoidEscape": true,
+            "allowTemplateLiterals": true
+        }],
+        "semi": 2,
+        "no-extra-semi": 2,
+        "comma-style": [2, "last"],
+        "wrap-iife": [2, "inside"],
+        "spaced-comment": [2, "always", {
+            "markers": ["*"]
+        }],
+        "eqeqeq": [2],
+        "arrow-body-style": [2, "as-needed"],
+        "accessor-pairs": [2, {
+            "getWithoutSet": false,
+            "setWithoutGet": false
+        }],
+        "brace-style": [2, "1tbs", {"allowSingleLine": true}],
+        "curly": [2, "multi-or-nest", "consistent"],
+        "new-parens": 2,
+        "func-call-spacing": 2,
+        "arrow-parens": [2, "as-needed"],
+        "prefer-const": 2,
+        "quote-props": [2, "consistent"],
+
+        // anti-patterns
+        "no-var": 2,
+        "no-with": 2,
+        "no-multi-str": 2,
+        "no-caller": 2,
+        "no-implied-eval": 2,
+        "no-labels": 2,
+        "no-new-object": 2,
+        "no-octal-escape": 2,
+        "no-self-compare": 2,
+        "no-shadow-restricted-names": 2,
+        "no-cond-assign": 2,
+        "no-debugger": 2,
+        "no-dupe-keys": 2,
+        "no-duplicate-case": 2,
+        "no-empty-character-class": 2,
+        "no-unreachable": 2,
+        "no-unsafe-negation": 2,
+        "radix": 2,
+        "valid-typeof": 2,
+        "no-implicit-globals": [2],
+
+        // es2015 features
+        "require-yield": 2,
+        "template-curly-spacing": [2, "never"],
+
+        // spacing details
+        "space-infix-ops": 2,
+        "space-in-parens": [2, "never"],
+        "space-before-function-paren": [2, "never"],
+        "no-whitespace-before-property": 2,
+        "keyword-spacing": [2, {
+            "overrides": {
+                "if": {"after": true},
+                "else": {"after": true},
+                "for": {"after": true},
+                "while": {"after": true},
+                "do": {"after": true},
+                "switch": {"after": true},
+                "return": {"after": true}
+            }
+        }],
+        "arrow-spacing": [2, {
+            "after": true,
+            "before": true
+        }],
+
+        // file whitespace
+        "no-multiple-empty-lines": [2, {"max": 2}],
+        "no-mixed-spaces-and-tabs": 2,
+        "no-trailing-spaces": 2,
+        "linebreak-style": [ process.platform === "win32" ? 0 : 2, "unix" ],
+        "indent": [2, 2, { "SwitchCase": 1, "CallExpression": {"arguments": 2}, "MemberExpression": 2 }],
+        "key-spacing": [2, {
+            "beforeColon": false
+        }]
+    }
+};
--- a/.gitignore
+++ b/.gitignore
@ -1,61 +1,20 @@
-# Logs
-logs
-*.log
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-
-# Runtime data
-pids
-*.pid
-*.seed
-*.pid.lock
-
-# Directory for instrumented libs generated by jscoverage/JSCover
-lib-cov
-
-# Coverage directory used by tools like istanbul
-coverage
-
-# nyc test coverage
-.nyc_output
-
-# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
-.grunt
-
-# Bower dependency directory (https://bower.io/)
-bower_components
-
-# node-waf configuration
-.lock-wscript
-
-# Compiled binary addons (https://nodejs.org/api/addons.html)
-build/Release
-
-# Dependency directories
-node_modules/
-jspm_packages/
-
-# TypeScript v1 declaration files
-typings/
-
-# Optional npm cache directory
-.npm
-
-# Optional eslint cache
-.eslintcache
-
-# Optional REPL history
-.node_repl_history
-
-# Output of 'npm pack'
-*.tgz
-
-# Yarn Integrity file
-.yarn-integrity
-
-# dotenv environment variables file
-.env
-
-# next.js build output
-.next
+/node_modules/
+/test/output-chromium
+/test/output-firefox
+/test/test-user-data-dir*
+/.local-chromium/
+/.local-browser/
+/.local-webkit/
+/.dev_profile*
+.DS_Store
+*.swp
+*.pyc
+.vscode
+package-lock.json
+yarn.lock
+/node6
+/src/chromium/protocol.d.ts
+/src/webkit/protocol.d.ts
+/utils/browser/playwright-web.js
+/index.d.ts
+lib/
--- a/.npmignore
+++ b/.npmignore
@ -0,0 +1,44 @@
+.appveyor.yml
+.gitattributes
+
+# no longer generated, but old checkouts might still have it
+node6
+
+# exclude all tests
+test
+utils/node6-transform
+
+# exclude source files
+src
+
+# repeats from .gitignore
+node_modules
+.local-chromium
+.local-browser
+.dev_profile*
+.DS_Store
+*.swp
+*.pyc
+.vscode
+package-lock.json
+/node6/test
+/node6/utils
+/test
+/utils
+/docs
+yarn.lock
+
+# other
+/.ci
+/examples
+.appveyour.yml
+.cirrus.yml
+.editorconfig
+.eslintignore
+.eslintrc.js
+.travis.yml
+README.md
+tsconfig.json
+
+# exclude types, see https://github.com/GoogleChrome/puppeteer/issues/3878
+/index.d.ts
--- a/.travis.yml
+++ b/.travis.yml
@ -0,0 +1,48 @@
+language: node_js
+dist: trusty
+addons:
+  apt:
+    packages:
+      # This is required to run new chrome on old trusty
+      - libnss3
+notifications:
+  email: false
+cache:
+  directories:
+    - node_modules
+# allow headful tests
+before_install:
+  - "sysctl kernel.unprivileged_userns_clone=1"
+  - "export DISPLAY=:99.0"
+  - "sh -e /etc/init.d/xvfb start"
+script:
+  - 'if [ "$NODE8" = "true" ]; then npm run lint; fi'
+  - 'if [ "$NODE8" = "true" ]; then npm run coverage; fi'
+  - 'if [ "$FIREFOX" = "true" ]; then npm run funit; fi'
+  - 'if [ "$NODE8" = "true" ]; then npm run test-doclint; fi'
+  - 'if [ "$NODE8" = "true" ]; then npm run test-types; fi'
+  - 'if [ "$NODE8" = "true" ]; then npm run bundle; fi'
+  - 'if [ "$NODE8" = "true" ]; then npm run unit-bundle; fi'
+jobs:
+  include:
+    - node_js: "8.16.0"
+      env:
+        - NODE8=true
+        - FLAKINESS_DASHBOARD_NAME="Travis Chromium (node8 + linux)"
+        - FLAKINESS_DASHBOARD_BUILD_URL="${TRAVIS_JOB_WEB_URL}"
+    - node_js: "8.16.0"
+      env:
+        - FIREFOX=true
+        - FLAKINESS_DASHBOARD_NAME="Travis Firefox (node8 + linux)"
+        - FLAKINESS_DASHBOARD_BUILD_URL="${TRAVIS_JOB_WEB_URL}"
+before_deploy: "npm run apply-next-version"
+deploy:
+  provider: npm
+  email: aslushnikov@gmail.com
+  api_key:
+    secure: Ng8o2KwJf90XCBNgUKK3jRZnwtdBSJatjYNmZBERJEqBWFTadFAp1NdhxZaqjnuG8aFYaH5bRJdL+EQBYUksVCbrv/gcaXeEFkwsfPfVX1QXGqu7NnZmtme2hbxppLQ7dEJ8hz2Z9K4vehqVOxmLabxvoupOumxEQMLCphVHh2FOmsm/S5JrRZqZ4V9k76eIc0/PiyfXNMdx5WTZjHbIRDIHRy9nqOXjFp2Rx3PMa3uU2fS8mTshYEYs151TA6e6VdHjqmBwEQC/M5tXbDlLCMNUr4JBtLTcL4OipNYjzkwD1N2xYlbSRqtvqqF4ifdvFhoI65a31GinlMC7Z/SH1Zy+d+/z3Mo7D63eYcsJVnsg9OYxTFy2piUntr0JqTBHtQoe/CvGxJmkcVt+H6YSkcBibSG9s9tG3qpAD5wBCFqqOYnfClX+YZziEd+Hngd9inxAf87qdvgVIZ5tPD2dygtE+te2/qoEHtvccv/HuS8MxNj5iKwlP7JaBPM6uAkazYqZP2R99I2ph9gNOEVuQLtk+3+OIdb8HWrEKUrJBgKhdKY1dvcKYElI+D8NRlyzrr6BnZfudACuAt2EtfKpfJ3mL+iRMFdBJ3ntLt93xBrB+j4z3pD0iWZcg1g3I742PFzQEHzyd/DDTP1yRTUoJeQWwoQRJyNO1m6Qk4wx77c=
+  on:
+    branch: master
+    condition: "$NODE8 = true"
+  skip_cleanup: true
+  tag: next
--- a/DeviceDescriptors.js
+++ b/DeviceDescriptors.js
@ -0,0 +1,23 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const {DeviceDescriptors} = require('./lib/DeviceDescriptors');
+
+const descriptors = DeviceDescriptors.slice();
+module.exports = descriptors;
+for (const device of descriptors)
+  module.exports[device.name] = device;
--- a/Errors.js
+++ b/Errors.js
@ -0,0 +1,17 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+module.exports = require('./lib/Errors');
--- a/browser_patches/README.md
+++ b/browser_patches/README.md
@ -0,0 +1,31 @@
+# Compiling and Uploading Builds
+
+### 1. Getting code
+
+```sh
+$ ./checkout.sh firefox/ # or ./checkout.sh webkit/
+```
+
+This command will create a `./firefox/checkout` folder that contains firefox GIT checkout.
+Checkout current branch will be set to `pwdev` and it will have all additional changes
+applied to the browser atop of the `./firefox/BASE_REVISION` version.
+
+### 2. Compiling
+
+> **NOTE** You might need to prepare your host environment according to browser build instructions:
+> - [firefox](https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions)
+> - [webkit](https://webkit.org/building-webkit/)
+
+```sh
+$ ./firefox/build.sh # or ./webkit/build.sh
+```
+
+### 3. Uploading builds to Azure CDN
+
+> **NOTE** You should have `$AZ_ACCOUNT_KEY` and `$AZ_ACCOUNT_NAME` variables set in your environment.
+
+```sh
+$ ./upload.sh firefox/ # or ./upload.sh webkit/
+```
+
+This will package archives and upload builds to Azure CDN.
--- a/browser_patches/check_cdn.sh
+++ b/browser_patches/check_cdn.sh
@ -0,0 +1,58 @@
+#!/bin/bash
+set -e
+set +x
+
+HOST="https://playwrightaccount.blob.core.windows.net/builds"
+ARCHIVES=(
+  "$HOST/firefox/%s/firefox-mac.zip"
+  "$HOST/firefox/%s/firefox-linux.zip"
+  "$HOST/firefox/%s/firefox-win.zip"
+  "$HOST/webkit/%s/minibrowser-linux.zip"
+  "$HOST/webkit/%s/minibrowser-mac10.14.zip"
+  "$HOST/webkit/%s/minibrowser-mac10.15.zip"
+)
+
+ALIASES=(
+  "FF-MAC"
+  "FF-LINUX"
+  "FF-WIN"
+  "WK-MAC-10.14"
+  "WK-MAC-10.15"
+  "WK-LINUX"
+)
+COLUMN="%-15s"
+
+# COLORS
+RED=$'\e[1;31m'
+GRN=$'\e[1;32m'
+YEL=$'\e[1;33m'
+END=$'\e[0m'
+
+# Read start revision if there's any.
+REVISION=$(git rev-parse HEAD)
+if [[ $# == 1 ]]; then
+  if ! git rev-parse $1; then
+    echo "ERROR: there is no $REVISION in this repo - pull from upstream?"
+    exit 1
+  fi
+  REVISION=$(git rev-parse $1)
+fi
+
+printf "%12s" ""
+for i in "${ALIASES[@]}"; do
+  printf $COLUMN $i
+done
+printf "\n"
+while true; do
+  printf "%-12s" ${REVISION:0:10}
+  for i in "${ARCHIVES[@]}"; do
+    URL=$(printf $i $REVISION)
+    if [[ $(curl -s -L -I $URL | head -1 | cut -f2 -d' ') == 200 ]]; then
+      printf ${GRN}$COLUMN${END} "YES"
+    else
+      printf ${RED}$COLUMN${END} "NO"
+    fi
+  done;
+  echo
+  REVISION=$(git rev-parse $REVISION^)
+done;
--- a/browser_patches/do_checkout.sh
+++ b/browser_patches/do_checkout.sh
@ -0,0 +1,136 @@
+#!/bin/bash
+set -e
+set +x
+
+function cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+
+if [[ ($1 == '--help') || ($1 == '-h') ]]; then
+  echo "usage: do_something.sh [firefox|webkit]"
+  echo
+  echo "Produces a browser checkout ready to be built."
+  echo
+  exit 0
+fi
+
+if [[ $# == 0 ]]; then
+  echo "missing browser: 'firefox' or 'webkit'"
+  echo "try './do_something.sh --help' for more information"
+  exit 1
+fi
+
+# FRIENDLY_CHECKOUT_PATH is used only for logging.
+FRIENDLY_CHECKOUT_PATH="";
+CHECKOUT_PATH=""
+# Export path is where we put the patches and BASE_REVISION
+REMOTE_URL=""
+BASE_BRANCH=""
+if [[ ("$1" == "firefox") || ("$1" == "firefox/") ]]; then
+  # we always apply our patches atop of beta since it seems to get better
+  # reliability guarantees.
+  BASE_BRANCH="beta"
+  FRIENDLY_CHECKOUT_PATH="//browser_patches/firefox/checkout";
+  CHECKOUT_PATH="$PWD/firefox/checkout"
+  REMOTE_URL="https://github.com/mozilla/gecko-dev"
+elif [[ ("$1" == "webkit") || ("$1" == "webkit/") ]]; then
+  # webkit has only a master branch.
+  BASE_BRANCH="master"
+  FRIENDLY_CHECKOUT_PATH="//browser_patches/webkit/checkout";
+  CHECKOUT_PATH="$PWD/webkit/checkout"
+  REMOTE_URL=""
+  REMOTE_URL="https://github.com/webkit/webkit"
+else
+  echo ERROR: unknown browser to export - "$1"
+  exit 1
+fi
+
+# if there's no checkout folder - checkout one.
+if ! [[ -d $CHECKOUT_PATH ]]; then
+  echo "-- $FRIENDLY_CHECKOUT_PATH is missing - checking out.."
+  git clone --single-branch --branch $BASE_BRANCH $REMOTE_URL $CHECKOUT_PATH
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH folder - OK"
+fi
+
+# if folder exists but not a git repository - bail out.
+if ! [[ -d $CHECKOUT_PATH/.git ]]; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH is not a git repository! Remove it and re-run the script."
+  exit 1
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH is a git repo - OK"
+fi
+
+# Switch to git repository.
+cd $CHECKOUT_PATH
+
+# Check if git repo is dirty.
+if [[ -n $(git status -s) ]]; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH has dirty GIT state - commit everything and re-run the script."
+  exit 1
+fi
+
+if [[ $(git config --get remote.origin.url) == "$REMOTE_URL" ]]; then
+  echo "-- checking git origin url to point to $REMOTE_URL - OK";
+else
+  echo "ERROR: git origin url DOES NOT point to $REMOTE_URL. Remove $FRIENDLY_CHECKOUT_PATH and re-run the script.";
+  exit 1
+fi
+
+# if there's no "BASE_BRANCH" branch - bail out.
+if ! git show-ref --verify --quiet refs/heads/$BASE_BRANCH; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH/ does not have '$BASE_BRANCH' branch! Remove checkout/ and re-run the script."
+  exit 1
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH has 'beta' branch - OK"
+fi
+
+if ! [[ -z $(git log --oneline origin/$BASE_BRANCH..$BASE_BRANCH) ]]; then
+  echo "ERROR: branch '$BASE_BRANCH' and branch 'origin/$BASE_BRANCH' have diverged - bailing out. Remove checkout/ and re-run the script."
+  exit 1;
+else
+  echo "-- checking that $BASE_BRANCH and origin/$BASE_BRANCH are not diverged - OK"
+fi
+
+git checkout $BASE_BRANCH
+git pull origin $BASE_BRANCH
+
+PINNED_COMMIT=$(cat ../BASE_REVISION)
+if ! git cat-file -e $PINNED_COMMIT^{commit}; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH/ does not include the BASE_REVISION (@$PINNED_COMMIT). Remove checkout/ and re-run the script."
+  exit 1
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH repo has BASE_REVISION (@$PINNED_COMMIT) commit - OK"
+fi
+
+# If there's already a PWDEV branch than we should check if it's fine to reset all changes
+# to it.
+if git show-ref --verify --quiet refs/heads/pwdev; then
+  read -p "Do you want to reset 'PWDEV' branch? (ALL CHANGES WILL BE LOST) Y/n " -n 1 -r
+  echo
+  # if it's not fine to reset branch - bail out.
+  if ! [[ $REPLY =~ ^[Yy]$ ]]; then
+    echo "If you want to keep the branch, than I can't do much! Bailing out!"
+    exit 1
+  else
+    git checkout pwdev
+    git reset --hard $PINNED_COMMIT
+    echo "-- PWDEV now points to BASE_REVISION (@$PINNED_COMMIT)"
+  fi
+else
+  # Otherwise just create a new branch.
+  git checkout -b pwdev
+  git reset --hard $PINNED_COMMIT
+  echo "-- created 'pwdev' branch that points to BASE_REVISION (@$PINNED_COMMIT)."
+fi
+
+echo "-- applying all patches"
+git am ../patches/*
+
+echo
+echo
+echo "DONE. Browser is ready to be built."
--- a/browser_patches/export.sh
+++ b/browser_patches/export.sh
@ -0,0 +1,115 @@
+#!/bin/bash
+set -e
+set +x
+
+cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+
+if [[ ($1 == '--help') || ($1 == '-h') ]]; then
+  echo "usage: export.sh [firefox|webkit] [custom_checkout_path]"
+  echo
+  echo "Exports BASE_REVISION and patch from the checkout to browser folder."
+  echo
+  echo "You can optionally specify custom_checkout_path if you have browser checkout somewhere else"
+  echo "and wish to export patches from it."
+  echo
+  exit 0
+fi
+
+if [[ $# == 0 ]]; then
+  echo "missing browser: 'firefox' or 'webkit'"
+  echo "try './export.sh --help' for more information"
+  exit 1
+fi
+
+# FRIENDLY_CHECKOUT_PATH is used only for logging.
+FRIENDLY_CHECKOUT_PATH="";
+CHECKOUT_PATH=""
+# Export path is where we put the patches and BASE_REVISION
+EXPORT_PATH=""
+BASE_BRANCH=""
+if [[ ("$1" == "firefox") || ("$1" == "firefox/") ]]; then
+  # we always apply our patches atop of beta since it seems to get better
+  # reliability guarantees.
+  BASE_BRANCH="origin/beta"
+  FRIENDLY_CHECKOUT_PATH="//browser_patches/firefox/checkout";
+  CHECKOUT_PATH="$PWD/firefox/checkout"
+  EXPORT_PATH="$PWD/firefox/"
+elif [[ ("$1" == "webkit") || ("$1" == "webkit/") ]]; then
+  # webkit has only a master branch.
+  BASE_BRANCH="origin/master"
+  FRIENDLY_CHECKOUT_PATH="//browser_patches/webkit/checkout";
+  CHECKOUT_PATH="$PWD/webkit/checkout"
+  EXPORT_PATH="$PWD/webkit/"
+else
+  echo ERROR: unknown browser to export - "$1"
+  exit 1
+fi
+
+# we will use this just for beauty.
+if [[ $# == 2 ]]; then
+  echo "WARNING: using custom checkout path $CHECKOUT_PATH"
+  CHECKOUT_PATH=$2
+  FRIENDLY_CHECKOUT_PATH="<custom_checkout>"
+fi
+
+# if there's no checkout folder - bail out.
+if ! [[ -d $CHECKOUT_PATH ]]; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH is missing - nothing to export."
+  exit 1;
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH exists - OK"
+fi
+
+# if folder exists but not a git repository - bail out.
+if ! [[ -d $CHECKOUT_PATH/.git ]]; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH is not a git repository! Nothing to export."
+  exit 1
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH is a git repo - OK"
+fi
+
+# Switch to git repository.
+cd $CHECKOUT_PATH
+
+# Check if git repo is dirty.
+if [[ -n $(git status -s) ]]; then
+  echo "ERROR: $FRIENDLY_CHECKOUT_PATH has dirty GIT state - aborting export."
+  exit 1
+else
+  echo "-- checking $FRIENDLY_CHECKOUT_PATH is clean - OK"
+fi
+
+CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+MERGE_BASE=$(git merge-base $BASE_BRANCH $CURRENT_BRANCH)
+echo "=============================================================="
+echo "    Repository:                $FRIENDLY_CHECKOUT_PATH"
+echo "    Changes between branches:  $BASE_BRANCH..$CURRENT_BRANCH"
+echo "    BASE_REVISION:             $MERGE_BASE"
+echo
+read -p "Export? Y/n " -n 1 -r
+echo
+# if it's not fine to reset branch - bail out.
+if ! [[ $REPLY =~ ^[Yy]$ ]]; then
+  echo "Exiting."
+  exit 1
+fi
+
+echo $MERGE_BASE > $EXPORT_PATH/BASE_REVISION
+git checkout -b tmpsquash_export_script $MERGE_BASE
+git merge --squash $CURRENT_BRANCH
+git commit -am "chore: bootstrap"
+PATCH_NAME=$(git format-patch -1 HEAD)
+mv $PATCH_NAME $EXPORT_PATH/patches/
+git checkout $CURRENT_BRANCH
+git branch -D tmpsquash_export_script
+
+# Increment BUILD_NUMBER
+BUILD_NUMBER=$(cat $EXPORT_PATH/BUILD_NUMBER)
+BUILD_NUMBER=$((BUILD_NUMBER+1))
+echo $BUILD_NUMBER > $EXPORT_PATH/BUILD_NUMBER
--- a/browser_patches/firefox/.gitignore
+++ b/browser_patches/firefox/.gitignore
@ -0,0 +1 @@
+/checkout
--- a/browser_patches/firefox/BASE_REVISION
+++ b/browser_patches/firefox/BASE_REVISION
@ -0,0 +1 @@
+46ca28eadfe840021e2ea496fa6b26f924fa135b
--- a/browser_patches/firefox/BUILD_NUMBER
+++ b/browser_patches/firefox/BUILD_NUMBER
@ -0,0 +1,2 @@
+1
+
--- a/browser_patches/firefox/README.md
+++ b/browser_patches/firefox/README.md
@ -0,0 +1,22 @@
+# Building Juggler (Linux & Mac)
+
+1. Run `./do_checkout.sh` script. This will create a "checkout" folder with gecko-dev mirror from
+GitHub and apply the PlayWright-specific patches.
+2. Run `./do_build.sh` script to compile browser. Note: you'll need to follow [build instructions](https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions) to setup host environment first.
+
+# Updating `FIREFOX_REVISION` and `//patches/*`
+
+The `./export.sh` script will export a patch that describes all the differences between the current branch in `./checkout`
+and the `beta` branch in `./checkout`.
+
+# Uploading to Azure CDN
+
+Uploading requires having both `AZ_ACCOUNT_KEY` and `AZ_ACCOUNT_NAME` env variables to be defined.
+
+The following sequence of steps will checkout, build and upload build to Azure CDN on both Linux and Mac:
+
+```sh
+$ ./do_checkout.sh
+$ ./build.sh
+$ ./upload.sh
+```
--- a/browser_patches/firefox/archive.sh
+++ b/browser_patches/firefox/archive.sh
@ -0,0 +1,53 @@
+#!/bin/bash
+
+if [[ ("$1" == "-h") || ("$1" == "--help") ]]; then
+  echo "usage: $0"
+  echo
+  echo "Generate distributable .zip archive from ./checkout folder that was previously built."
+  echo
+  exit 0
+fi
+
+set -e
+set -x
+
+createZIPForLinuxOrMac() {
+  cd checkout
+  local zipname=$1
+  local OBJ_FOLDER=$(ls -1 | grep obj-)
+  if [[ $OBJ_FOLDER == "" ]]; then
+    echo "ERROR: cannot find obj-* folder in the checkout/. Did you build?"
+    exit 1;
+  fi
+  if ! [[ -d $OBJ_FOLDER/dist/firefox ]]; then
+    echo "ERROR: cannot find $OBJ_FOLDER/dist/firefox folder in the checkout/. Did you build?"
+    exit 1;
+  fi
+  # Copy the libstdc++ version we linked against.
+  # TODO(aslushnikov): this won't be needed with official builds.
+  if [[ "$(uname)" == "Linux" ]]; then
+    cp /usr/lib/x86_64-linux-gnu/libstdc++.so.6 $OBJ_FOLDER/dist/firefox/libstdc++.so.6
+  fi
+
+  # tar resulting directory and cleanup TMP.
+  cd $OBJ_FOLDER/dist
+  zip -r ../../../$zipname firefox
+  cd -
+}
+
+cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+
+if [[ "$(uname)" == "Darwin" ]]; then
+  createZIPForLinuxOrMac "firefox-mac.zip"
+elif [[ "$(uname)" == "Linux" ]]; then
+  createZIPForLinuxOrMac "firefox-linux.zip"
+else
+  echo "ERROR: cannot upload on this platform!" 1>&2
+  exit 1;
+fi
--- a/browser_patches/firefox/build.sh
+++ b/browser_patches/firefox/build.sh
@ -0,0 +1,45 @@
+#!/bin/bash
+set -e
+set +x
+
+function cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+
+cd checkout
+
+if ! [[ $(git rev-parse --abbrev-ref HEAD) == "pwdev" ]]; then
+  echo "ERROR: Cannot build any branch other than PWDEV"
+  exit 1;
+else
+  echo "-- checking git branch is PWDEV - OK"
+fi
+
+if [[ "$(uname)" == "Darwin" ]]; then
+  # Firefox currently does not build on 10.15 out of the box - it requires SDK for 10.14.
+  # Make sure the SDK is out there.
+  if [[ $(sw_vers -productVersion) == "10.15" ]]; then
+    if ! [[ -d $HOME/SDK-archive/MacOSX10.14.sdk ]]; then
+      echo "As of Nov 2019, Firefox does not build on Mac 10.15 without 10.14 SDK."
+      echo "Check out instructions on getting 10.14 sdk at https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Mac_OS_X_Prerequisites"
+      echo "and make sure to put SDK to $HOME/SDK-archive/MacOSX10.14.sdk/"
+      exit 1
+    else
+      echo "-- configuting .mozconfig with 10.14 SDK path"
+      echo "ac_add_options --with-macos-sdk=$HOME/SDK-archive/MacOSX10.14.sdk/" > .mozconfig
+    fi
+  fi
+  echo "-- building on Mac"
+elif [[ "$(uname)" == "Linux" ]]; then
+  echo "-- building on Linux"
+else
+  echo "ERROR: cannot upload on this platform!" 1>&2
+  exit 1;
+fi
+
+./mach build
+./mach package
--- a/browser_patches/firefox/patches/0001-chore-bootstrap.patch
+++ b/browser_patches/firefox/patches/0001-chore-bootstrap.patch
--- a/browser_patches/upload.sh
+++ b/browser_patches/upload.sh
@ -0,0 +1,68 @@
+#!/bin/bash
+set -e
+set +x
+
+cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+
+if [[ ($1 == '--help') || ($1 == '-h') ]]; then
+  echo "usage: $0 [firefox|webkit]"
+  echo
+  echo "Archive and upload a browser"
+  echo
+  echo "NOTE: \$AZ_ACCOUNT_KEY (azure account name) and \$AZ_ACCOUNT_NAME (azure account name)"
+  echo "env variables are required to upload builds to CDN."
+  exit 0
+fi
+
+if [[ $# == 0 ]]; then
+  echo "missing browser: 'firefox' or 'webkit'"
+  echo "try '$0 --help' for more information"
+  exit 1
+fi
+
+if [[ (-z $AZ_ACCOUNT_KEY) || (-z $AZ_ACCOUNT_NAME) ]]; then
+  echo "ERROR: Either \$AZ_ACCOUNT_KEY or \$AZ_ACCOUNT_NAME environment variable is missing."
+  echo "       'Azure Account Name' and 'Azure Account Key' secrets that are required"
+  echo "       to upload builds ot Azure CDN."
+  exit 1
+fi
+
+ARCHIVE_SCRIPT=""
+BROWSER_NAME=""
+BUILD_NUMBER=""
+if [[ ("$1" == "firefox") || ("$1" == "firefox/") ]]; then
+  # we always apply our patches atop of beta since it seems to get better
+  # reliability guarantees.
+  ARCHIVE_FOLDER="$PWD/firefox"
+  BUILD_NUMBER=$(cat "$PWD/firefox/BUILD_NUMBER")
+  ARCHIVE_SCRIPT="$PWD/firefox/archive.sh"
+  BROWSER_NAME="firefox"
+elif [[ ("$1" == "webkit") || ("$1" == "webkit/") ]]; then
+  ARCHIVE_FOLDER="$PWD/webkit"
+  BUILD_NUMBER=$(cat "$PWD/webkit/BUILD_NUMBER")
+  ARCHIVE_SCRIPT="$PWD/webkit/archive.sh"
+  BROWSER_NAME="webkit"
+else
+  echo ERROR: unknown browser to export - "$1"
+  exit 1
+fi
+
+if ! [[ -z $(ls $ARCHIVE_FOLDER | grep '.zip') ]]; then
+  echo ERROR: .zip file already exists in $ARCHIVE_FOLDER!
+  echo Remove manually all zip files and re-run the script.
+  exit 1
+fi
+
+$ARCHIVE_SCRIPT
+ZIP_NAME=$(ls $ARCHIVE_FOLDER | grep '.zip')
+ZIP_PATH=$ARCHIVE_FOLDER/$ZIP_NAME
+BLOB_NAME="$BROWSER_NAME/$BUILD_NUMBER/$ZIP_NAME"
+az storage blob upload -c builds --account-key $AZ_ACCOUNT_KEY --account-name $AZ_ACCOUNT_NAME -f $ZIP_PATH -n "$BLOB_NAME"
+echo "Uploaded $(du -h "$ZIP_PATH" | awk '{print $1}') as $BLOB_NAME"
+rm $ZIP_PATH
--- a/browser_patches/webkit/.gitignore
+++ b/browser_patches/webkit/.gitignore
@ -0,0 +1 @@
+/checkout
--- a/browser_patches/webkit/BASE_REVISION
+++ b/browser_patches/webkit/BASE_REVISION
@ -0,0 +1 @@
+cadee71e3e832cc0b78184a714ade07d9a6d3173
--- a/browser_patches/webkit/BUILD_NUMBER
+++ b/browser_patches/webkit/BUILD_NUMBER
@ -0,0 +1,2 @@
+1
+
--- a/browser_patches/webkit/archive.sh
+++ b/browser_patches/webkit/archive.sh
@ -0,0 +1,85 @@
+#!/bin/bash
+
+if [[ ("$1" == "-h") || ("$1" == "--help") ]]; then
+  echo "usage: $0"
+  echo
+  echo "Generate distributable .zip archive from ./checkout folder that was previously built."
+  echo
+  exit 0
+fi
+
+set -e
+set -x
+
+main() {
+  cd checkout
+
+  if [[ "$(uname)" == "Darwin" ]]; then
+    createZipForMac
+  elif [[ "$(uname)" == "Linux" ]]; then
+    createZipForLinux
+  else
+    echo "ERROR: cannot upload on this platform!" 1>&2
+    exit 1;
+  fi
+}
+
+createZipForLinux() {
+  # create a TMP directory to copy all necessary files
+  local tmpdir=$(mktemp -d -t webkit-deploy-XXXXXXXXXX)
+  mkdir -p $tmpdir
+
+  # copy all relevant binaries
+  cp -t $tmpdir ./WebKitBuild/Release/bin/MiniBrowser ./WebKitBuild/Release/bin/WebKit*Process
+  # copy runner
+  cp -t $tmpdir ../pw_run.sh
+  # copy protocol
+  node ../concat_protocol.js > $tmpdir/protocol.json
+  # copy all relevant shared objects
+  LD_LIBRARY_PATH="$PWD/WebKitBuild/DependenciesGTK/Root/lib" ldd WebKitBuild/Release/bin/MiniBrowser | grep -o '[^ ]*WebKitBuild/[^ ]*' | xargs cp -t $tmpdir
+
+  # we failed to nicely build libgdk_pixbuf - expect it in the env
+  rm $tmpdir/libgdk_pixbuf*
+
+  # tar resulting directory and cleanup TMP.
+  local zipname="minibrowser-linux.zip"
+  zip -jr ../$zipname $tmpdir
+  rm -rf $tmpdir
+}
+
+createZipForMac() {
+  # create a TMP directory to copy all necessary files
+  local tmpdir=$(mktemp -d)
+
+  # copy all relevant files
+  ditto {./WebKitBuild/Release,$tmpdir}/com.apple.WebKit.Networking.xpc
+  ditto {./WebKitBuild/Release,$tmpdir}/com.apple.WebKit.Plugin.64.xpc
+  ditto {./WebKitBuild/Release,$tmpdir}/com.apple.WebKit.WebContent.xpc
+  ditto {./WebKitBuild/Release,$tmpdir}/JavaScriptCore.framework
+  ditto {./WebKitBuild/Release,$tmpdir}/libwebrtc.dylib
+  ditto {./WebKitBuild/Release,$tmpdir}/MiniBrowser.app
+  ditto {./WebKitBuild/Release,$tmpdir}/PluginProcessShim.dylib
+  ditto {./WebKitBuild/Release,$tmpdir}/SecItemShim.dylib
+  ditto {./WebKitBuild/Release,$tmpdir}/WebCore.framework
+  ditto {./WebKitBuild/Release,$tmpdir}/WebInspectorUI.framework
+  ditto {./WebKitBuild/Release,$tmpdir}/WebKit.framework
+  ditto {./WebKitBuild/Release,$tmpdir}/WebKitLegacy.framework
+  ditto {..,$tmpdir}/pw_run.sh
+  # copy protocol
+  node ../concat_protocol.js > $tmpdir/protocol.json
+
+  # zip resulting directory and cleanup TMP.
+  local MAC_MAJOR_MINOR_VERSION=$(sw_vers -productVersion | grep -o '^\d\+.\d\+')
+  local zipname="minibrowser-mac-$MAC_MAJOR_MINOR_VERSION.zip"
+  ditto -c -k $tmpdir ../$zipname
+  rm -rf $tmpdir
+}
+
+cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+main "$@"
--- a/browser_patches/webkit/build.sh
+++ b/browser_patches/webkit/build.sh
@ -0,0 +1,29 @@
+#!/bin/bash
+set -e
+set +x
+
+function cleanup() {
+  cd $OLD_DIR
+}
+
+OLD_DIR=$(pwd -P)
+cd "$(dirname "$0")"
+trap cleanup EXIT
+
+cd checkout
+
+if ! [[ $(git rev-parse --abbrev-ref HEAD) == "pwdev" ]]; then
+  echo "ERROR: Cannot build any branch other than PWDEV"
+  exit 1;
+else
+  echo "-- checking git branch is PWDEV - OK"
+fi
+
+if [[ "$(uname)" == "Darwin" ]]; then
+  ./Tools/Scripts/build-webkit --release
+elif [[ "$(uname)" == "Linux" ]]; then
+  ./Tools/Scripts/build-webkit --gtk --release MiniBrowser
+else
+  echo "ERROR: cannot upload on this platform!" 1>&2
+  exit 1;
+fi
--- a/browser_patches/webkit/concat_protocol.js
+++ b/browser_patches/webkit/concat_protocol.js
@ -0,0 +1,6 @@
+const fs = require('fs');
+const path = require('path');
+const protocolDir = path.join(__dirname, './checkout/Source/JavaScriptCore/inspector/protocol');
+const files = fs.readdirSync(protocolDir).filter(f => f.endsWith('.json')).map(f => path.join(protocolDir, f));
+const json = files.map(file => JSON.parse(fs.readFileSync(file)));
+console.log(JSON.stringify(json));
--- a/browser_patches/webkit/patches/0001-chore-bootstrap.patch
+++ b/browser_patches/webkit/patches/0001-chore-bootstrap.patch
--- a/browser_patches/webkit/pw_run.sh
+++ b/browser_patches/webkit/pw_run.sh
@ -0,0 +1,40 @@
+#!/bin/bash
+
+function runOSX() {
+  # if script is run as-is
+  if [ -d $SCRIPT_PATH/checkout/WebKitBuild/Release/MiniBrowser.app ]; then
+    DYLIB_PATH="$SCRIPT_PATH/checkout/WebKitBuild/Release"
+  elif [ -d $SCRIPT_PATH/MiniBrowser.app ]; then
+    DYLIB_PATH="$SCRIPT_PATH"
+  else
+    echo "Cannot find a MiniBrowser.app in neither location" 1>&2
+    exit 1
+  fi
+  MINIBROWSER="$DYLIB_PATH/MiniBrowser.app/Contents/MacOS/MiniBrowser"
+  DYLD_FRAMEWORK_PATH=$DYLIB_PATH DYLD_LIBRARY_PATH=$DYLIB_PATH $MINIBROWSER "$@"
+}
+
+function runLinux() {
+  # if script is run as-is
+  if [ -d $SCRIPT_PATH/checkout/WebKitBuild ]; then
+    LD_PATH="$SCRIPT_PATH/checkout/WebKitBuild/DependenciesGTK/Root/lib:$SCRIPT_PATH/checkout/WebKitBuild/Release/bin"
+    MINIBROWSER="$SCRIPT_PATH/checkout/WebKitBuild/Release/bin/MiniBrowser"
+  elif [ -f $SCRIPT_PATH/MiniBrowser ]; then
+    LD_PATH="$SCRIPT_PATH"
+    MINIBROWSER="$SCRIPT_PATH/MiniBrowser"
+  else
+    echo "Cannot find a MiniBrowser.app in neither location" 1>&2
+    exit 1
+  fi
+  LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$LD_PATH $MINIBROWSER "$@"
+}
+
+SCRIPT_PATH="$(cd "$(dirname "$0")" ; pwd -P)"
+if [ "$(uname)" == "Darwin" ]; then
+  runOSX "$@"
+elif [ "$(uname)" == "Linux" ]; then
+  runLinux "$@"
+else
+  echo "ERROR: cannot run on this platform!" 1>&2
+  exit 1;
+fi
--- a/chromium.js
+++ b/chromium.js
@ -0,0 +1,30 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const {helper} = require('./lib/helper');
+const api = require('./lib/api');
+for (const className in api.Chromium) {
+  // Playwright-web excludes certain classes from bundle, e.g. BrowserFetcher.
+  if (typeof api.Chromium[className] === 'function')
+    helper.installAsyncStackHooks(api.Chromium[className]);
+}
+
+// If node does not support async await, use the compiled version.
+const {Playwright} = require('./lib/chromium/Playwright');
+const packageJson = require('./package.json');
+const isPlaywrightCore = packageJson.name === 'playwright-core';
+
+module.exports = new Playwright(__dirname, packageJson.playwright.chromium_revision, isPlaywrightCore);
--- a/docs/api.md
+++ b/docs/api.md
--- a/examples/block-images.js
+++ b/examples/block-images.js
@ -0,0 +1,36 @@
+/**
+ * Copyright 2017 Google Inc., PhantomJS Authors All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+  await page.setRequestInterception(true);
+  page.on('request', request => {
+    if (request.resourceType() === 'image')
+      request.abort();
+    else
+      request.continue();
+  });
+  await page.goto('https://news.google.com/news/');
+  await page.screenshot({path: 'news.png', fullPage: true});
+
+  await browser.close();
+})();
+
--- a/examples/custom-event.js
+++ b/examples/custom-event.js
@ -0,0 +1,48 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+
+  // Define a window.onCustomEvent function on the page.
+  await page.exposeFunction('onCustomEvent', e => {
+    console.log(`${e.type} fired`, e.detail || '');
+  });
+
+  /**
+   * Attach an event listener to page to capture a custom event on page load/navigation.
+   * @param {string} type Event name.
+   * @return {!Promise}
+   */
+  function listenFor(type) {
+    return page.evaluateOnNewDocument(type => {
+      document.addEventListener(type, e => {
+        window.onCustomEvent({type, detail: e.detail});
+      });
+    }, type);
+  }
+
+  await listenFor('app-ready'); // Listen for "app-ready" custom event on page load.
+
+  await page.goto('https://www.chromestatus.com/features', {waitUntil: 'networkidle0'});
+
+  await browser.close();
+})();
--- a/examples/detect-sniff.js
+++ b/examples/detect-sniff.js
@ -0,0 +1,44 @@
+/**
+ * Copyright 2017 Google Inc., PhantomJS Authors All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+function sniffDetector() {
+  const userAgent = window.navigator.userAgent;
+  const platform = window.navigator.platform;
+
+  window.navigator.__defineGetter__('userAgent', function() {
+    window.navigator.sniffed = true;
+    return userAgent;
+  });
+
+  window.navigator.__defineGetter__('platform', function() {
+    window.navigator.sniffed = true;
+    return platform;
+  });
+}
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+  await page.evaluateOnNewDocument(sniffDetector);
+  await page.goto('https://www.google.com', {waitUntil: 'networkidle2'});
+  console.log('Sniffed: ' + (await page.evaluate(() => !!navigator.sniffed)));
+
+  await browser.close();
+})();
--- a/examples/pdf.js
+++ b/examples/pdf.js
@ -0,0 +1,33 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+  await page.goto('https://news.ycombinator.com', {waitUntil: 'networkidle2'});
+  // page.pdf() is currently supported only in headless mode.
+  // @see https://bugs.chromium.org/p/chromium/issues/detail?id=753118
+  await page.pdf({
+    path: 'hn.pdf',
+    format: 'letter'
+  });
+
+  await browser.close();
+})();
--- a/examples/proxy.js
+++ b/examples/proxy.js
@ -0,0 +1,35 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+(async() => {
+  const browser = await playwright.launch({
+    // Launch chromium using a proxy server on port 9876.
+    // More on proxying:
+    //    https://www.chromium.org/developers/design-documents/network-settings
+    args: [
+      '--proxy-server=127.0.0.1:9876',
+      // Use proxy for localhost URLs
+      '--proxy-bypass-list=<-loopback>',
+    ]
+  });
+  const page = await browser.newPage();
+  await page.goto('https://google.com');
+  await browser.close();
+})();
--- a/examples/screenshot-fullpage.js
+++ b/examples/screenshot-fullpage.js
@ -0,0 +1,29 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+const devices = require('playwright/DeviceDescriptors');
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+  await page.emulate(devices['iPhone 6']);
+  await page.goto('https://www.nytimes.com/');
+  await page.screenshot({path: 'full.png', fullPage: true});
+  await browser.close();
+})();
--- a/examples/screenshot.js
+++ b/examples/screenshot.js
@ -0,0 +1,27 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+  await page.goto('http://example.com');
+  await page.screenshot({path: 'example.png'});
+  await browser.close();
+})();
--- a/examples/search.js
+++ b/examples/search.js
@ -0,0 +1,55 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @fileoverview Search developers.google.com/web for articles tagged
+ * "Headless Chrome" and scrape results from the results page.
+ */
+
+'use strict';
+
+const playwright = require('playwright');
+
+(async() => {
+  const browser = await playwright.launch();
+  const page = await browser.newPage();
+
+  await page.goto('https://developers.google.com/web/');
+
+  // Type into search box.
+  await page.type('#searchbox input', 'Headless Chrome');
+
+  // Wait for suggest overlay to appear and click "show all results".
+  const allResultsSelector = '.devsite-suggest-all-results';
+  await page.waitForSelector(allResultsSelector);
+  await page.click(allResultsSelector);
+
+  // Wait for the results page to load and display the results.
+  const resultsSelector = '.gsc-results .gsc-thumbnail-inside a.gs-title';
+  await page.waitForSelector(resultsSelector);
+
+  // Extract the results from the page.
+  const links = await page.evaluate(resultsSelector => {
+    const anchors = Array.from(document.querySelectorAll(resultsSelector));
+    return anchors.map(anchor => {
+      const title = anchor.textContent.split('|')[0].trim();
+      return `${title} - ${anchor.href}`;
+    });
+  }, resultsSelector);
+  console.log(links.join('\n'));
+
+  await browser.close();
+})();
--- a/firefox.js
+++ b/firefox.js
@ -0,0 +1,29 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const {helper} = require('./lib/helper');
+const api = require('./lib/api');
+for (const className in api.Firefox) {
+  // Playwright-web excludes certain classes from bundle, e.g. BrowserFetcher.
+  if (typeof api.Firefox[className] === 'function')
+    helper.installAsyncStackHooks(api.Firefox[className]);
+}
+
+// If node does not support async await, use the compiled version.
+const {Playwright} = require('./lib/firefox/Playwright');
+const packageJson = require('./package.json');
+
+module.exports = new Playwright(__dirname, packageJson.playwright.firefox_revision);
--- a/install.js
+++ b/install.js
@ -0,0 +1,137 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// playwright-core should not install anything.
+if (require('./package.json').name === 'playwright-core')
+  return;
+
+for (const browser of ['Chromium', 'Firefox', 'WebKit']) {
+  const templates = [
+    `PLAYWRIGHT_SKIP_${browser}_DOWNLOAD`,
+    `NPM_CONFIG_PLAYWRIGHT_SKIP_${browser}_DOWNLOAD`,
+    `NPM_PACKAGE_CONFIG_PLAYWRIGHT_SKIP_${browser}_DOWNLOAD`,
+  ];
+  const varNames = [...templates.map(n => n.toUpperCase()), ...templates.map(n => n.toLowerCase())];
+  for (const varName of varNames) {
+    if (process.env[varName.toUpperCase()]) {
+      logPolitely(`**INFO** Skipping ${browser} download. "${varName}" environment variable was found.`);
+      return;
+    }
+  }
+}
+
+const downloadHost = process.env.PLAYWRIGHT_DOWNLOAD_HOST || process.env.npm_config_playwright_download_host || process.env.npm_package_config_playwright_download_host;
+
+
+if (require('fs').existsSync(require('path').join(__dirname, 'src'))) {
+  try {
+    require('child_process').execSync('npm run build', {
+      stdio: 'ignore'
+    });
+  } catch (e) {
+  }
+}
+
+(async function() {
+  const {generateWebKitProtocol, generateChromeProtocol} = require('./utils/protocol-types-generator/') ;
+
+  const chromeRevision = await downloadBrowser('chromium', require('./chromium').createBrowserFetcher({host: downloadHost}));
+  await generateChromeProtocol(chromeRevision);
+
+  await downloadBrowser('firefox', require('./firefox').createBrowserFetcher({host: downloadHost}));
+
+  const webkitRevision = await downloadBrowser('webkit', require('./webkit').createBrowserFetcher({host: downloadHost}));
+  await generateWebKitProtocol(webkitRevision);
+})();
+function getRevision(browser) {
+  if (browser === 'chromium')
+    return process.env.PLAYWRIGHT_CHROMIUM_REVISION || process.env.npm_config_playwright_chromium_revision || process.env.npm_package_config_playwright_chromium_revision || require('./package.json').playwright.chromium_revision;
+  if (browser === 'firefox')
+    return process.env.PLAYWRIGHT_FIREFOX_REVISION || process.env.npm_config_playwright_firefox_revision || process.env.npm_package_config_playwright_firefox_revision || require('./package.json').playwright.firefox_revision;
+  if (browser === 'webkit')
+    return process.env.PLAYWRIGHT_WEBKIT_REVISION || process.env.npm_config_playwright_webkit_revision || process.env.npm_package_config_playwright_webkit_revision || require('./package.json').playwright.webkit_revision;
+}
+async function downloadBrowser(browser, browserFetcher) {
+  const revision = getRevision(browser);
+
+  const revisionInfo = browserFetcher.revisionInfo(revision);
+
+  // Do nothing if the revision is already downloaded.
+  if (revisionInfo.local)
+    return revisionInfo;
+
+  // Override current environment proxy settings with npm configuration, if any.
+  const NPM_HTTPS_PROXY = process.env.npm_config_https_proxy || process.env.npm_config_proxy;
+  const NPM_HTTP_PROXY = process.env.npm_config_http_proxy || process.env.npm_config_proxy;
+  const NPM_NO_PROXY = process.env.npm_config_no_proxy;
+
+  if (NPM_HTTPS_PROXY)
+    process.env.HTTPS_PROXY = NPM_HTTPS_PROXY;
+  if (NPM_HTTP_PROXY)
+    process.env.HTTP_PROXY = NPM_HTTP_PROXY;
+  if (NPM_NO_PROXY)
+    process.env.NO_PROXY = NPM_NO_PROXY;
+
+  let progressBar = null;
+  let lastDownloadedBytes = 0;
+  function onProgress(downloadedBytes, totalBytes) {
+    if (!progressBar) {
+      const ProgressBar = require('progress');
+      progressBar = new ProgressBar(`Downloading ${browser} ${revision} - ${toMegabytes(totalBytes)} [:bar] :percent :etas `, {
+        complete: '=',
+        incomplete: ' ',
+        width: 20,
+        total: totalBytes,
+      });
+    }
+    const delta = downloadedBytes - lastDownloadedBytes;
+    lastDownloadedBytes = downloadedBytes;
+    progressBar.tick(delta);
+  }
+
+  try {
+    await browserFetcher.download(revisionInfo.revision, onProgress);
+  } catch(error) {
+    console.error(`ERROR: Failed to download ${browser} ${revision}! Set "PLAYWRIGHT_SKIP_${browser.toUpperCase()}_DOWNLOAD" env variable to skip download.`);
+    console.error(error);
+    process.exit(1);
+  }
+  logPolitely(`${browser} downloaded to ${revisionInfo.folderPath}`);
+  const localRevisions = await browserFetcher.localRevisions();
+  // Remove previous chromium revisions.
+  const cleanupOldVersions = localRevisions.filter(revision => revision !== revisionInfo.revision).map(revision => browserFetcher.remove(revision));
+  await Promise.all([...cleanupOldVersions]);
+  if (browser === 'firefox') {
+    const installFirefoxPreferences = require('./misc/install-preferences');
+    await installFirefoxPreferences(revisionInfo.executablePath);
+  }
+  return revisionInfo;
+}
+
+
+function toMegabytes(bytes) {
+  const mb = bytes / 1024 / 1024;
+  return `${Math.round(mb * 10) / 10} Mb`;
+}
+
+function logPolitely(toBeLogged) {
+  const logLevel = process.env.npm_config_loglevel;
+  const logLevelDisplay = ['silent', 'error', 'warn'].indexOf(logLevel) > -1;
+
+  if (!logLevelDisplay)
+    console.log(toBeLogged);
+}
+
--- a/misc/00-playwright-prefs.js
+++ b/misc/00-playwright-prefs.js
@ -0,0 +1,3 @@
+// Any comment. You must start the file with a single-line comment!
+pref("general.config.filename", "playwright.cfg");
+pref("general.config.obscure_value", 0);
--- a/misc/install-preferences.js
+++ b/misc/install-preferences.js
@ -0,0 +1,59 @@
+const os = require('os');
+const fs = require('fs');
+const path = require('path');
+const util = require('util');
+
+// Install browser preferences after downloading and unpacking
+// firefox instances.
+// Based on:   https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Enterprise_deployment_before_60#Configuration
+async function installFirefoxPreferences(executablePath) {
+  const firefoxFolder = path.dirname(executablePath);
+  const mkdirAsync = util.promisify(fs.mkdir.bind(fs));
+
+  let prefPath = '';
+  let configPath = '';
+  if (os.platform() === 'darwin') {
+    prefPath = path.join(firefoxFolder, '..', 'Resources', 'defaults', 'pref');
+    configPath = path.join(firefoxFolder, '..', 'Resources');
+  } else if (os.platform() === 'linux') {
+    if (!fs.existsSync(path.join(firefoxFolder, 'browser', 'defaults')))
+      await mkdirAsync(path.join(firefoxFolder, 'browser', 'defaults'));
+    if (!fs.existsSync(path.join(firefoxFolder, 'browser', 'defaults', 'preferences')))
+      await mkdirAsync(path.join(firefoxFolder, 'browser', 'defaults', 'preferences'));
+    prefPath = path.join(firefoxFolder, 'browser', 'defaults', 'preferences');
+    configPath = firefoxFolder;
+  } else if (os.platform() === 'win32') {
+    prefPath = path.join(firefoxFolder, 'defaults', 'pref');
+    configPath = firefoxFolder;
+  } else {
+    throw new Error('Unsupported platform: ' + os.platform());
+  }
+
+  await Promise.all([
+    copyFile({
+      from: path.join(__dirname, '00-playwright-prefs.js'),
+      to: path.join(prefPath, '00-playwright-prefs.js'),
+    }),
+    copyFile({
+      from: path.join(__dirname, 'playwright.cfg'),
+      to: path.join(configPath, 'playwright.cfg'),
+    }),
+  ]);
+}
+
+function copyFile({from, to}) {
+  var rd = fs.createReadStream(from);
+  var wr = fs.createWriteStream(to);
+  return new Promise(function(resolve, reject) {
+    rd.on('error', reject);
+    wr.on('error', reject);
+    wr.on('finish', resolve);
+    rd.pipe(wr);
+  }).catch(function(error) {
+    rd.destroy();
+    wr.end();
+    throw error;
+  });
+}
+
+module.exports = installFirefoxPreferences;
--- a/misc/playwright.cfg
+++ b/misc/playwright.cfg
@ -0,0 +1,212 @@
+// Any comment. You must start the file with a comment!
+
+// Make sure Shield doesn't hit the network.
+// pref("app.normandy.api_url", "");
+pref("app.normandy.enabled", false);
+
+// Disable updater
+pref("app.update.enabled", false);
+// make absolutely sure it is really off
+pref("app.update.auto", false);
+pref("app.update.mode", 0);
+pref("app.update.service.enabled", false);
+
+// Dislabe newtabpage
+pref("browser.startup.homepage", 'about:blank');
+pref("browser.newtabpage.enabled", false);
+// Disable topstories
+pref("browser.newtabpage.activity-stream.feeds.section.topstories", false);
+
+// DevTools JSONViewer sometimes fails to load dependencies with its require.js.
+// This doesn't affect Playwright operations, but spams console with a lot of
+// unpleasant errors.
+// (bug 1424372)
+pref("devtools.jsonview.enabled", false);
+
+// Increase the APZ content response timeout in tests to 1 minute.
+// This is to accommodate the fact that test environments tends to be
+// slower than production environments (with the b2g emulator being
+// the slowest of them all), resulting in the production timeout value
+// sometimes being exceeded and causing false-positive test failures.
+//
+// (bug 1176798, bug 1177018, bug 1210465)
+pref("apz.content_response_timeout", 60000);
+
+// Allow creating files in content process - required for
+// |Page.setFileInputFiles| protocol method.
+pref("dom.file.createInChild", true);
+
+// Indicate that the download panel has been shown once so that
+// whichever download test runs first doesn't show the popup
+// inconsistently.
+pref("browser.download.panel.shown", true);
+
+// Background thumbnails in particular cause grief, and disabling
+// thumbnails in general cannot hurt
+pref("browser.pagethumbnails.capturing_disabled", true);
+
+// Disable safebrowsing components.
+pref("browser.safebrowsing.blockedURIs.enabled", false);
+pref("browser.safebrowsing.downloads.enabled", false);
+pref("browser.safebrowsing.passwords.enabled", false);
+pref("browser.safebrowsing.malware.enabled", false);
+pref("browser.safebrowsing.phishing.enabled", false);
+
+// Disable updates to search engines.
+pref("browser.search.update", false);
+
+// Do not restore the last open set of tabs if the browser has crashed
+pref("browser.sessionstore.resume_from_crash", false);
+
+// Don't check for the default web browser during startup.
+pref("browser.shell.checkDefaultBrowser", false);
+
+// Do not redirect user when a milstone upgrade of Firefox is detected
+pref("browser.startup.homepage_override.mstone", "ignore");
+
+// Disable browser animations (tabs, fullscreen, sliding alerts)
+pref("toolkit.cosmeticAnimations.enabled", false);
+
+// Close the window when the last tab gets closed
+pref("browser.tabs.closeWindowWithLastTab", true);
+
+// Do not allow background tabs to be zombified on Android, otherwise for
+// tests that open additional tabs, the test harness tab itself might get
+// unloaded
+pref("browser.tabs.disableBackgroundZombification", false);
+
+// Do not warn when closing all open tabs
+pref("browser.tabs.warnOnClose", false);
+
+// Do not warn when closing all other open tabs
+pref("browser.tabs.warnOnCloseOtherTabs", false);
+
+// Do not warn when multiple tabs will be opened
+pref("browser.tabs.warnOnOpen", false);
+
+// Disable first run splash page on Windows 10
+pref("browser.usedOnWindows10.introURL", "");
+
+// Disable the UI tour.
+//
+// Should be set in profile.
+pref("browser.uitour.enabled", false);
+
+// Turn off search suggestions in the location bar so as not to trigger
+// network connections.
+pref("browser.urlbar.suggest.searches", false);
+
+// Do not warn on quitting Firefox
+pref("browser.warnOnQuit", false);
+
+// Do not show datareporting policy notifications which can
+// interfere with tests
+pref(
+  "datareporting.healthreport.documentServerURI",
+  "http://%(server)s/dummy/healthreport/",
+);
+pref("datareporting.healthreport.logging.consoleEnabled", false);
+pref("datareporting.healthreport.service.enabled", false);
+pref("datareporting.healthreport.service.firstRun", false);
+pref("datareporting.healthreport.uploadEnabled", false);
+pref("datareporting.policy.dataSubmissionEnabled", false);
+pref("datareporting.policy.dataSubmissionPolicyAccepted", false);
+pref("datareporting.policy.dataSubmissionPolicyBypassNotification", true);
+
+// Automatically unload beforeunload alerts
+pref("dom.disable_beforeunload", false);
+
+// Disable popup-blocker
+pref("dom.disable_open_during_load", false);
+
+// Disable the ProcessHangMonitor
+pref("dom.ipc.reportProcessHangs", false);
+
+// Disable slow script dialogues
+pref("dom.max_chrome_script_run_time", 0);
+pref("dom.max_script_run_time", 0);
+
+// Only load extensions from the application and user profile
+// AddonManager.SCOPE_PROFILE + AddonManager.SCOPE_APPLICATION
+pref("extensions.autoDisableScopes", 0);
+pref("extensions.enabledScopes", 5);
+
+// Disable metadata caching for installed add-ons by default
+pref("extensions.getAddons.cache.enabled", false);
+
+// Disable installing any distribution extensions or add-ons.
+pref("extensions.installDistroAddons", false);
+
+// Turn off extension updates so they do not bother tests
+pref("extensions.update.enabled", false);
+pref("extensions.update.notifyUser", false);
+
+// Make sure opening about:addons will not hit the network
+pref(
+  "extensions.webservice.discoverURL",
+  "http://%(server)s/dummy/discoveryURL",
+);
+
+pref("extensions.screenshots.disabled", true);
+pref("extensions.screenshots.upload-disabled", true);
+
+// Allow the application to have focus even it runs in the background
+pref("focusmanager.testmode", true);
+
+// Disable useragent updates
+pref("general.useragent.updates.enabled", false);
+
+// Always use network provider for geolocation tests so we bypass the
+// macOS dialog raised by the corelocation provider
+pref("geo.provider.testing", true);
+
+// Do not scan Wifi
+pref("geo.wifi.scan", false);
+
+// Show chrome errors and warnings in the error console
+pref("javascript.options.showInConsole", true);
+
+// Do not prompt with long usernames or passwords in URLs
+pref("network.http.phishy-userpass-length", 255);
+
+// Do not prompt for temporary redirects
+pref("network.http.prompt-temp-redirect", false);
+
+// Disable speculative connections so they are not reported as leaking
+// when they are hanging around
+pref("network.http.speculative-parallel-limit", 0);
+
+// Do not automatically switch between offline and online
+pref("network.manage-offline-status", false);
+
+// Make sure SNTP requests do not hit the network
+pref("network.sntp.pools", "%(server)s");
+
+// Local documents have access to all other local documents,
+// including directory listings
+pref("security.fileuri.strict_origin_policy", false);
+
+// Tests do not wait for the notification button security delay
+pref("security.notification_enable_delay", 0);
+
+// Ensure blocklist updates do not hit the network
+pref("services.settings.server", "http://%(server)s/dummy/blocklist/");
+
+// Do not automatically fill sign-in forms with known usernames and
+// passwords
+pref("signon.autofillForms", false);
+
+// Disable password capture, so that tests that include forms are not
+// influenced by the presence of the persistent doorhanger notification
+pref("signon.rememberSignons", false);
+
+// Disable first-run welcome page
+pref("startup.homepage_welcome_url", "about:blank");
+pref("startup.homepage_welcome_url.additional", "");
+
+// Prevent starting into safe mode after application crashes
+pref("toolkit.startup.max_resumed_crashes", -1);
+lockPref("toolkit.crashreporter.enabled", false);
+
+// Disable crash reporter.
+Components.classes["@mozilla.org/toolkit/crash-reporter;1"].getService(Components.interfaces.nsICrashReporter).submitReports = false;
--- a/package.json
+++ b/package.json
@ -0,0 +1,75 @@
+{
+  "name": "playwright",
+  "version": "2.0.0-post",
+  "description": "A high-level API to control headless Chrome over the DevTools Protocol",
+  "main": "index.js",
+  "repository": "github:Microsoft/playwright",
+  "engines": {
+    "node": ">=8.16.0"
+  },
+  "playwright": {
+    "chromium_revision": "706915",
+    "firefox_revision": "1",
+    "webkit_revision": "1"
+  },
+  "scripts": {
+    "unit": "node test/test.js",
+    "funit": "cross-env BROWSER=firefox node test/test.js",
+    "wunit": "cross-env BROWSER=webkit node test/test.js",
+    "debug-unit": "node --inspect-brk test/test.js",
+    "test-doclint": "node utils/doclint/check_public_api/test/test.js && node utils/doclint/preprocessor/test.js",
+    "test": "npm run lint --silent && npm run coverage && npm run test-doclint && npm run test-types && node utils/testrunner/test/test.js",
+    "install": "node install.js",
+    "lint": "([ \"$CI\" = true ] && eslint --quiet -f codeframe --ext js,ts ./src || eslint --ext js,ts ./src) && npm run tsc && npm run doc",
+    "doc": "node utils/doclint/cli.js",
+    "coverage": "cross-env COVERAGE=true npm run unit",
+    "tsc": "tsc -p .",
+    "build": "npm run tsc",
+    "watch": "tsc -w -p .",
+    "apply-next-version": "node utils/apply_next_version.js",
+    "bundle": "npx browserify -r ./index.js:playwright -o utils/browser/playwright-web.js",
+    "test-types": "node utils/doclint/generate_types && npx -p typescript@2.1 tsc -p utils/doclint/generate_types/test/",
+    "unit-bundle": "node utils/browser/test.js"
+  },
+  "author": "The Chromium Authors",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "debug": "^4.1.0",
+    "extract-zip": "^1.6.6",
+    "https-proxy-agent": "^3.0.0",
+    "mime": "^2.0.3",
+    "progress": "^2.0.1",
+    "proxy-from-env": "^1.0.0",
+    "rimraf": "^2.6.1",
+    "ws": "^6.1.0"
+  },
+  "devDependencies": {
+    "@types/debug": "0.0.31",
+    "@types/extract-zip": "^1.6.2",
+    "@types/mime": "^2.0.0",
+    "@types/node": "^8.10.34",
+    "@types/rimraf": "^2.0.2",
+    "@types/ws": "^6.0.1",
+    "@typescript-eslint/eslint-plugin": "^2.6.1",
+    "@typescript-eslint/parser": "^2.6.1",
+    "commonmark": "^0.28.1",
+    "cross-env": "^5.0.5",
+    "eslint": "^6.6.0",
+    "esprima": "^4.0.0",
+    "jpeg-js": "^0.3.4",
+    "minimist": "^1.2.0",
+    "ncp": "^2.0.0",
+    "pixelmatch": "^4.0.2",
+    "pngjs": "^3.3.3",
+    "text-diff": "^1.0.1",
+    "typescript": "3.6.3"
+  },
+  "browser": {
+    "./lib/BrowserFetcher.js": false,
+    "ws": "./utils/browser/WebSocket",
+    "fs": false,
+    "child_process": false,
+    "rimraf": false,
+    "readline": false
+  }
+}
--- a/src/.eslintrc.js
+++ b/src/.eslintrc.js
@ -0,0 +1,16 @@
+module.exports = {
+    "extends": "../.eslintrc.js",
+    /**
+     * ESLint rules
+     *
+     * All available rules: http://eslint.org/docs/rules/
+     *
+     * Rules take the following form:
+     *   "rule-name", [severity, { opts }]
+     * Severity: 2 == error, 1 == warning, 0 == off.
+     */
+    "rules": {
+        "no-console": [2, { "allow": ["warn", "error", "assert", "timeStamp", "time", "timeEnd"] }],
+        "no-debugger": 0,
+    }
+};
--- a/src/ConnectionTransport.ts
+++ b/src/ConnectionTransport.ts
@ -0,0 +1,6 @@
+export interface ConnectionTransport {
+  send(s: string): void;
+  close(): void;
+  onmessage?: (message: string) => void,
+  onclose?: () => void,
+}
--- a/src/DeviceDescriptors.ts
+++ b/src/DeviceDescriptors.ts
@ -0,0 +1,871 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export const DeviceDescriptors = [
+  {
+    'name': 'Blackberry PlayBook',
+    'userAgent': 'Mozilla/5.0 (PlayBook; U; RIM Tablet OS 2.1.0; en-US) AppleWebKit/536.2+ (KHTML like Gecko) Version/7.2.1.0 Safari/536.2+',
+    'viewport': {
+      'width': 600,
+      'height': 1024,
+      'deviceScaleFactor': 1,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Blackberry PlayBook landscape',
+    'userAgent': 'Mozilla/5.0 (PlayBook; U; RIM Tablet OS 2.1.0; en-US) AppleWebKit/536.2+ (KHTML like Gecko) Version/7.2.1.0 Safari/536.2+',
+    'viewport': {
+      'width': 1024,
+      'height': 600,
+      'deviceScaleFactor': 1,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'BlackBerry Z30',
+    'userAgent': 'Mozilla/5.0 (BB10; Touch) AppleWebKit/537.10+ (KHTML, like Gecko) Version/10.0.9.2372 Mobile Safari/537.10+',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'BlackBerry Z30 landscape',
+    'userAgent': 'Mozilla/5.0 (BB10; Touch) AppleWebKit/537.10+ (KHTML, like Gecko) Version/10.0.9.2372 Mobile Safari/537.10+',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Galaxy Note 3',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.3; en-us; SM-N900T Build/JSS15J) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Galaxy Note 3 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.3; en-us; SM-N900T Build/JSS15J) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Galaxy Note II',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.1; en-us; GT-N7100 Build/JRO03C) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Galaxy Note II landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.1; en-us; GT-N7100 Build/JRO03C) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Galaxy S III',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.0; en-us; GT-I9300 Build/IMM76D) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Galaxy S III landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.0; en-us; GT-I9300 Build/IMM76D) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Galaxy S5',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 5.0; SM-G900P Build/LRX21T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Galaxy S5 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 5.0; SM-G900P Build/LRX21T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPad',
+    'userAgent': 'Mozilla/5.0 (iPad; CPU OS 11_0 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) Version/11.0 Mobile/15A5341f Safari/604.1',
+    'viewport': {
+      'width': 768,
+      'height': 1024,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPad landscape',
+    'userAgent': 'Mozilla/5.0 (iPad; CPU OS 11_0 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) Version/11.0 Mobile/15A5341f Safari/604.1',
+    'viewport': {
+      'width': 1024,
+      'height': 768,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPad Mini',
+    'userAgent': 'Mozilla/5.0 (iPad; CPU OS 11_0 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) Version/11.0 Mobile/15A5341f Safari/604.1',
+    'viewport': {
+      'width': 768,
+      'height': 1024,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPad Mini landscape',
+    'userAgent': 'Mozilla/5.0 (iPad; CPU OS 11_0 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) Version/11.0 Mobile/15A5341f Safari/604.1',
+    'viewport': {
+      'width': 1024,
+      'height': 768,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPad Pro',
+    'userAgent': 'Mozilla/5.0 (iPad; CPU OS 11_0 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) Version/11.0 Mobile/15A5341f Safari/604.1',
+    'viewport': {
+      'width': 1024,
+      'height': 1366,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPad Pro landscape',
+    'userAgent': 'Mozilla/5.0 (iPad; CPU OS 11_0 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) Version/11.0 Mobile/15A5341f Safari/604.1',
+    'viewport': {
+      'width': 1366,
+      'height': 1024,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 4',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_2 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) Version/7.0 Mobile/11D257 Safari/9537.53',
+    'viewport': {
+      'width': 320,
+      'height': 480,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 4 landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 7_1_2 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) Version/7.0 Mobile/11D257 Safari/9537.53',
+    'viewport': {
+      'width': 480,
+      'height': 320,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 5',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.0 Mobile/14E304 Safari/602.1',
+    'viewport': {
+      'width': 320,
+      'height': 568,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 5 landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.0 Mobile/14E304 Safari/602.1',
+    'viewport': {
+      'width': 568,
+      'height': 320,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 6',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 375,
+      'height': 667,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 6 landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 667,
+      'height': 375,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 6 Plus',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 414,
+      'height': 736,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 6 Plus landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 736,
+      'height': 414,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 7',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 375,
+      'height': 667,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 7 landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 667,
+      'height': 375,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 7 Plus',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 414,
+      'height': 736,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 7 Plus landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 736,
+      'height': 414,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 8',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 375,
+      'height': 667,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 8 landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 667,
+      'height': 375,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone 8 Plus',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 414,
+      'height': 736,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone 8 Plus landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 736,
+      'height': 414,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone SE',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.0 Mobile/14E304 Safari/602.1',
+    'viewport': {
+      'width': 320,
+      'height': 568,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone SE landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.0 Mobile/14E304 Safari/602.1',
+    'viewport': {
+      'width': 568,
+      'height': 320,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone X',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 375,
+      'height': 812,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone X landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1',
+    'viewport': {
+      'width': 812,
+      'height': 375,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'iPhone XR',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 12_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Mobile/15E148 Safari/604.1',
+    'viewport': {
+      'width': 414,
+      'height': 896,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'iPhone XR landscape',
+    'userAgent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 12_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Mobile/15E148 Safari/604.1',
+    'viewport': {
+      'width': 896,
+      'height': 414,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'JioPhone 2',
+    'userAgent': 'Mozilla/5.0 (Mobile; LYF/F300B/LYF-F300B-001-01-15-130718-i;Android; rv:48.0) Gecko/48.0 Firefox/48.0 KAIOS/2.5',
+    'viewport': {
+      'width': 240,
+      'height': 320,
+      'deviceScaleFactor': 1,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'JioPhone 2 landscape',
+    'userAgent': 'Mozilla/5.0 (Mobile; LYF/F300B/LYF-F300B-001-01-15-130718-i;Android; rv:48.0) Gecko/48.0 Firefox/48.0 KAIOS/2.5',
+    'viewport': {
+      'width': 320,
+      'height': 240,
+      'deviceScaleFactor': 1,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Kindle Fire HDX',
+    'userAgent': 'Mozilla/5.0 (Linux; U; en-us; KFAPWI Build/JDQ39) AppleWebKit/535.19 (KHTML, like Gecko) Silk/3.13 Safari/535.19 Silk-Accelerated=true',
+    'viewport': {
+      'width': 800,
+      'height': 1280,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Kindle Fire HDX landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; U; en-us; KFAPWI Build/JDQ39) AppleWebKit/535.19 (KHTML, like Gecko) Silk/3.13 Safari/535.19 Silk-Accelerated=true',
+    'viewport': {
+      'width': 1280,
+      'height': 800,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'LG Optimus L70',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.4.2; en-us; LGMS323 Build/KOT49I.MS32310c) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 384,
+      'height': 640,
+      'deviceScaleFactor': 1.25,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'LG Optimus L70 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; U; Android 4.4.2; en-us; LGMS323 Build/KOT49I.MS32310c) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 640,
+      'height': 384,
+      'deviceScaleFactor': 1.25,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Microsoft Lumia 550',
+    'userAgent': 'Mozilla/5.0 (Windows Phone 10.0; Android 4.2.1; Microsoft; Lumia 550) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Mobile Safari/537.36 Edge/14.14263',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Microsoft Lumia 950',
+    'userAgent': 'Mozilla/5.0 (Windows Phone 10.0; Android 4.2.1; Microsoft; Lumia 950) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Mobile Safari/537.36 Edge/14.14263',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 4,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Microsoft Lumia 950 landscape',
+    'userAgent': 'Mozilla/5.0 (Windows Phone 10.0; Android 4.2.1; Microsoft; Lumia 950) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2486.0 Mobile Safari/537.36 Edge/14.14263',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 4,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 10',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 6.0.1; Nexus 10 Build/MOB31T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Safari/537.36',
+    'viewport': {
+      'width': 800,
+      'height': 1280,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 10 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 6.0.1; Nexus 10 Build/MOB31T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Safari/537.36',
+    'viewport': {
+      'width': 1280,
+      'height': 800,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 4',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 4.4.2; Nexus 4 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 384,
+      'height': 640,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 4 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 4.4.2; Nexus 4 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 640,
+      'height': 384,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 5',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 360,
+      'height': 640,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 5 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 640,
+      'height': 360,
+      'deviceScaleFactor': 3,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 5X',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0.0; Nexus 5X Build/OPR4.170623.006) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 412,
+      'height': 732,
+      'deviceScaleFactor': 2.625,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 5X landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0.0; Nexus 5X Build/OPR4.170623.006) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 732,
+      'height': 412,
+      'deviceScaleFactor': 2.625,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 6',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 7.1.1; Nexus 6 Build/N6F26U) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 412,
+      'height': 732,
+      'deviceScaleFactor': 3.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 6 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 7.1.1; Nexus 6 Build/N6F26U) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 732,
+      'height': 412,
+      'deviceScaleFactor': 3.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 6P',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0.0; Nexus 6P Build/OPP3.170518.006) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 412,
+      'height': 732,
+      'deviceScaleFactor': 3.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 6P landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0.0; Nexus 6P Build/OPP3.170518.006) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 732,
+      'height': 412,
+      'deviceScaleFactor': 3.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nexus 7',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 6.0.1; Nexus 7 Build/MOB30X) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Safari/537.36',
+    'viewport': {
+      'width': 600,
+      'height': 960,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nexus 7 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 6.0.1; Nexus 7 Build/MOB30X) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Safari/537.36',
+    'viewport': {
+      'width': 960,
+      'height': 600,
+      'deviceScaleFactor': 2,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nokia Lumia 520',
+    'userAgent': 'Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 520)',
+    'viewport': {
+      'width': 320,
+      'height': 533,
+      'deviceScaleFactor': 1.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nokia Lumia 520 landscape',
+    'userAgent': 'Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 520)',
+    'viewport': {
+      'width': 533,
+      'height': 320,
+      'deviceScaleFactor': 1.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Nokia N9',
+    'userAgent': 'Mozilla/5.0 (MeeGo; NokiaN9) AppleWebKit/534.13 (KHTML, like Gecko) NokiaBrowser/8.5.0 Mobile Safari/534.13',
+    'viewport': {
+      'width': 480,
+      'height': 854,
+      'deviceScaleFactor': 1,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Nokia N9 landscape',
+    'userAgent': 'Mozilla/5.0 (MeeGo; NokiaN9) AppleWebKit/534.13 (KHTML, like Gecko) NokiaBrowser/8.5.0 Mobile Safari/534.13',
+    'viewport': {
+      'width': 854,
+      'height': 480,
+      'deviceScaleFactor': 1,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Pixel 2',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0; Pixel 2 Build/OPD3.170816.012) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 411,
+      'height': 731,
+      'deviceScaleFactor': 2.625,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Pixel 2 landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0; Pixel 2 Build/OPD3.170816.012) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 731,
+      'height': 411,
+      'deviceScaleFactor': 2.625,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  },
+  {
+    'name': 'Pixel 2 XL',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0.0; Pixel 2 XL Build/OPD1.170816.004) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 411,
+      'height': 823,
+      'deviceScaleFactor': 3.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': false
+    }
+  },
+  {
+    'name': 'Pixel 2 XL landscape',
+    'userAgent': 'Mozilla/5.0 (Linux; Android 8.0.0; Pixel 2 XL Build/OPD1.170816.004) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3765.0 Mobile Safari/537.36',
+    'viewport': {
+      'width': 823,
+      'height': 411,
+      'deviceScaleFactor': 3.5,
+      'isMobile': true,
+      'hasTouch': true,
+      'isLandscape': true
+    }
+  }
+];
--- a/src/Errors.ts
+++ b/src/Errors.ts
@ -0,0 +1,26 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class CustomError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = this.constructor.name;
+    Error.captureStackTrace(this, this.constructor);
+  }
+}
+
+export class TimeoutError extends CustomError {}
--- a/src/Events.ts
+++ b/src/Events.ts
@ -0,0 +1,55 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export const Events = {
+  Page: {
+    Close: 'close',
+    Console: 'console',
+    Dialog: 'dialog',
+    DOMContentLoaded: 'domcontentloaded',
+    Error: 'error',
+    // Can't use just 'error' due to node.js special treatment of error events.
+    // @see https://nodejs.org/api/events.html#events_error_events
+    PageError: 'pageerror',
+    Request: 'request',
+    Response: 'response',
+    RequestFailed: 'requestfailed',
+    RequestFinished: 'requestfinished',
+    FrameAttached: 'frameattached',
+    FrameDetached: 'framedetached',
+    FrameNavigated: 'framenavigated',
+    Load: 'load',
+    Metrics: 'metrics',
+    Popup: 'popup',
+    WorkerCreated: 'workercreated',
+    WorkerDestroyed: 'workerdestroyed',
+  },
+
+  Browser: {
+    TargetCreated: 'targetcreated',
+    TargetDestroyed: 'targetdestroyed',
+    TargetChanged: 'targetchanged',
+    Disconnected: 'disconnected'
+  },
+
+  BrowserContext: {
+    TargetCreated: 'targetcreated',
+    TargetDestroyed: 'targetdestroyed',
+    TargetChanged: 'targetchanged',
+  },
+
+};
--- a/src/TimeoutSettings.ts
+++ b/src/TimeoutSettings.ts
@ -0,0 +1,45 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const DEFAULT_TIMEOUT = 30000;
+
+export class TimeoutSettings {
+  private _defaultTimeout: number | null = null;
+  private _defaultNavigationTimeout: number | null = null;
+
+  setDefaultTimeout(timeout: number) {
+    this._defaultTimeout = timeout;
+  }
+
+  setDefaultNavigationTimeout(timeout: number) {
+    this._defaultNavigationTimeout = timeout;
+  }
+
+  navigationTimeout(): number {
+    if (this._defaultNavigationTimeout !== null)
+      return this._defaultNavigationTimeout;
+    if (this._defaultTimeout !== null)
+      return this._defaultTimeout;
+    return DEFAULT_TIMEOUT;
+  }
+
+  timeout() {
+    if (this._defaultTimeout !== null)
+      return this._defaultTimeout;
+    return DEFAULT_TIMEOUT;
+  }
+}
--- a/src/USKeyboardLayout.ts
+++ b/src/USKeyboardLayout.ts
@ -0,0 +1,285 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+type KeyDefinition = {
+  keyCode?: number
+  shiftKeyCode?: number
+  key?: string
+  shiftKey?: string
+  code?: string
+  text?: string
+  shiftText?: string
+  location ?: number
+}
+
+export const keyDefinitions: { [s: string]: KeyDefinition; } = {
+  '0': {'keyCode': 48, 'key': '0', 'code': 'Digit0'},
+  '1': {'keyCode': 49, 'key': '1', 'code': 'Digit1'},
+  '2': {'keyCode': 50, 'key': '2', 'code': 'Digit2'},
+  '3': {'keyCode': 51, 'key': '3', 'code': 'Digit3'},
+  '4': {'keyCode': 52, 'key': '4', 'code': 'Digit4'},
+  '5': {'keyCode': 53, 'key': '5', 'code': 'Digit5'},
+  '6': {'keyCode': 54, 'key': '6', 'code': 'Digit6'},
+  '7': {'keyCode': 55, 'key': '7', 'code': 'Digit7'},
+  '8': {'keyCode': 56, 'key': '8', 'code': 'Digit8'},
+  '9': {'keyCode': 57, 'key': '9', 'code': 'Digit9'},
+  'Power': {'key': 'Power', 'code': 'Power'},
+  'Eject': {'key': 'Eject', 'code': 'Eject'},
+  'Abort': {'keyCode': 3, 'code': 'Abort', 'key': 'Cancel'},
+  'Help': {'keyCode': 6, 'code': 'Help', 'key': 'Help'},
+  'Backspace': {'keyCode': 8, 'code': 'Backspace', 'key': 'Backspace'},
+  'Tab': {'keyCode': 9, 'code': 'Tab', 'key': 'Tab'},
+  'Numpad5': {'keyCode': 12, 'shiftKeyCode': 101, 'key': 'Clear', 'code': 'Numpad5', 'shiftKey': '5', 'location': 3},
+  'NumpadEnter': {'keyCode': 13, 'code': 'NumpadEnter', 'key': 'Enter', 'text': '\r', 'location': 3},
+  'Enter': {'keyCode': 13, 'code': 'Enter', 'key': 'Enter', 'text': '\r'},
+  '\r': {'keyCode': 13, 'code': 'Enter', 'key': 'Enter', 'text': '\r'},
+  '\n': {'keyCode': 13, 'code': 'Enter', 'key': 'Enter', 'text': '\r'},
+  'ShiftLeft': {'keyCode': 16, 'code': 'ShiftLeft', 'key': 'Shift', 'location': 1},
+  'ShiftRight': {'keyCode': 16, 'code': 'ShiftRight', 'key': 'Shift', 'location': 2},
+  'ControlLeft': {'keyCode': 17, 'code': 'ControlLeft', 'key': 'Control', 'location': 1},
+  'ControlRight': {'keyCode': 17, 'code': 'ControlRight', 'key': 'Control', 'location': 2},
+  'AltLeft': {'keyCode': 18, 'code': 'AltLeft', 'key': 'Alt', 'location': 1},
+  'AltRight': {'keyCode': 18, 'code': 'AltRight', 'key': 'Alt', 'location': 2},
+  'Pause': {'keyCode': 19, 'code': 'Pause', 'key': 'Pause'},
+  'CapsLock': {'keyCode': 20, 'code': 'CapsLock', 'key': 'CapsLock'},
+  'Escape': {'keyCode': 27, 'code': 'Escape', 'key': 'Escape'},
+  'Convert': {'keyCode': 28, 'code': 'Convert', 'key': 'Convert'},
+  'NonConvert': {'keyCode': 29, 'code': 'NonConvert', 'key': 'NonConvert'},
+  'Space': {'keyCode': 32, 'code': 'Space', 'key': ' '},
+  'Numpad9': {'keyCode': 33, 'shiftKeyCode': 105, 'key': 'PageUp', 'code': 'Numpad9', 'shiftKey': '9', 'location': 3},
+  'PageUp': {'keyCode': 33, 'code': 'PageUp', 'key': 'PageUp'},
+  'Numpad3': {'keyCode': 34, 'shiftKeyCode': 99, 'key': 'PageDown', 'code': 'Numpad3', 'shiftKey': '3', 'location': 3},
+  'PageDown': {'keyCode': 34, 'code': 'PageDown', 'key': 'PageDown'},
+  'End': {'keyCode': 35, 'code': 'End', 'key': 'End'},
+  'Numpad1': {'keyCode': 35, 'shiftKeyCode': 97, 'key': 'End', 'code': 'Numpad1', 'shiftKey': '1', 'location': 3},
+  'Home': {'keyCode': 36, 'code': 'Home', 'key': 'Home'},
+  'Numpad7': {'keyCode': 36, 'shiftKeyCode': 103, 'key': 'Home', 'code': 'Numpad7', 'shiftKey': '7', 'location': 3},
+  'ArrowLeft': {'keyCode': 37, 'code': 'ArrowLeft', 'key': 'ArrowLeft'},
+  'Numpad4': {'keyCode': 37, 'shiftKeyCode': 100, 'key': 'ArrowLeft', 'code': 'Numpad4', 'shiftKey': '4', 'location': 3},
+  'Numpad8': {'keyCode': 38, 'shiftKeyCode': 104, 'key': 'ArrowUp', 'code': 'Numpad8', 'shiftKey': '8', 'location': 3},
+  'ArrowUp': {'keyCode': 38, 'code': 'ArrowUp', 'key': 'ArrowUp'},
+  'ArrowRight': {'keyCode': 39, 'code': 'ArrowRight', 'key': 'ArrowRight'},
+  'Numpad6': {'keyCode': 39, 'shiftKeyCode': 102, 'key': 'ArrowRight', 'code': 'Numpad6', 'shiftKey': '6', 'location': 3},
+  'Numpad2': {'keyCode': 40, 'shiftKeyCode': 98, 'key': 'ArrowDown', 'code': 'Numpad2', 'shiftKey': '2', 'location': 3},
+  'ArrowDown': {'keyCode': 40, 'code': 'ArrowDown', 'key': 'ArrowDown'},
+  'Select': {'keyCode': 41, 'code': 'Select', 'key': 'Select'},
+  'Open': {'keyCode': 43, 'code': 'Open', 'key': 'Execute'},
+  'PrintScreen': {'keyCode': 44, 'code': 'PrintScreen', 'key': 'PrintScreen'},
+  'Insert': {'keyCode': 45, 'code': 'Insert', 'key': 'Insert'},
+  'Numpad0': {'keyCode': 45, 'shiftKeyCode': 96, 'key': 'Insert', 'code': 'Numpad0', 'shiftKey': '0', 'location': 3},
+  'Delete': {'keyCode': 46, 'code': 'Delete', 'key': 'Delete'},
+  'NumpadDecimal': {'keyCode': 46, 'shiftKeyCode': 110, 'code': 'NumpadDecimal', 'key': '\u0000', 'shiftKey': '.', 'location': 3},
+  'Digit0': {'keyCode': 48, 'code': 'Digit0', 'shiftKey': ')', 'key': '0'},
+  'Digit1': {'keyCode': 49, 'code': 'Digit1', 'shiftKey': '!', 'key': '1'},
+  'Digit2': {'keyCode': 50, 'code': 'Digit2', 'shiftKey': '@', 'key': '2'},
+  'Digit3': {'keyCode': 51, 'code': 'Digit3', 'shiftKey': '#', 'key': '3'},
+  'Digit4': {'keyCode': 52, 'code': 'Digit4', 'shiftKey': '$', 'key': '4'},
+  'Digit5': {'keyCode': 53, 'code': 'Digit5', 'shiftKey': '%', 'key': '5'},
+  'Digit6': {'keyCode': 54, 'code': 'Digit6', 'shiftKey': '^', 'key': '6'},
+  'Digit7': {'keyCode': 55, 'code': 'Digit7', 'shiftKey': '&', 'key': '7'},
+  'Digit8': {'keyCode': 56, 'code': 'Digit8', 'shiftKey': '*', 'key': '8'},
+  'Digit9': {'keyCode': 57, 'code': 'Digit9', 'shiftKey': '\(', 'key': '9'},
+  'KeyA': {'keyCode': 65, 'code': 'KeyA', 'shiftKey': 'A', 'key': 'a'},
+  'KeyB': {'keyCode': 66, 'code': 'KeyB', 'shiftKey': 'B', 'key': 'b'},
+  'KeyC': {'keyCode': 67, 'code': 'KeyC', 'shiftKey': 'C', 'key': 'c'},
+  'KeyD': {'keyCode': 68, 'code': 'KeyD', 'shiftKey': 'D', 'key': 'd'},
+  'KeyE': {'keyCode': 69, 'code': 'KeyE', 'shiftKey': 'E', 'key': 'e'},
+  'KeyF': {'keyCode': 70, 'code': 'KeyF', 'shiftKey': 'F', 'key': 'f'},
+  'KeyG': {'keyCode': 71, 'code': 'KeyG', 'shiftKey': 'G', 'key': 'g'},
+  'KeyH': {'keyCode': 72, 'code': 'KeyH', 'shiftKey': 'H', 'key': 'h'},
+  'KeyI': {'keyCode': 73, 'code': 'KeyI', 'shiftKey': 'I', 'key': 'i'},
+  'KeyJ': {'keyCode': 74, 'code': 'KeyJ', 'shiftKey': 'J', 'key': 'j'},
+  'KeyK': {'keyCode': 75, 'code': 'KeyK', 'shiftKey': 'K', 'key': 'k'},
+  'KeyL': {'keyCode': 76, 'code': 'KeyL', 'shiftKey': 'L', 'key': 'l'},
+  'KeyM': {'keyCode': 77, 'code': 'KeyM', 'shiftKey': 'M', 'key': 'm'},
+  'KeyN': {'keyCode': 78, 'code': 'KeyN', 'shiftKey': 'N', 'key': 'n'},
+  'KeyO': {'keyCode': 79, 'code': 'KeyO', 'shiftKey': 'O', 'key': 'o'},
+  'KeyP': {'keyCode': 80, 'code': 'KeyP', 'shiftKey': 'P', 'key': 'p'},
+  'KeyQ': {'keyCode': 81, 'code': 'KeyQ', 'shiftKey': 'Q', 'key': 'q'},
+  'KeyR': {'keyCode': 82, 'code': 'KeyR', 'shiftKey': 'R', 'key': 'r'},
+  'KeyS': {'keyCode': 83, 'code': 'KeyS', 'shiftKey': 'S', 'key': 's'},
+  'KeyT': {'keyCode': 84, 'code': 'KeyT', 'shiftKey': 'T', 'key': 't'},
+  'KeyU': {'keyCode': 85, 'code': 'KeyU', 'shiftKey': 'U', 'key': 'u'},
+  'KeyV': {'keyCode': 86, 'code': 'KeyV', 'shiftKey': 'V', 'key': 'v'},
+  'KeyW': {'keyCode': 87, 'code': 'KeyW', 'shiftKey': 'W', 'key': 'w'},
+  'KeyX': {'keyCode': 88, 'code': 'KeyX', 'shiftKey': 'X', 'key': 'x'},
+  'KeyY': {'keyCode': 89, 'code': 'KeyY', 'shiftKey': 'Y', 'key': 'y'},
+  'KeyZ': {'keyCode': 90, 'code': 'KeyZ', 'shiftKey': 'Z', 'key': 'z'},
+  'MetaLeft': {'keyCode': 91, 'code': 'MetaLeft', 'key': 'Meta', 'location': 1},
+  'MetaRight': {'keyCode': 92, 'code': 'MetaRight', 'key': 'Meta', 'location': 2},
+  'ContextMenu': {'keyCode': 93, 'code': 'ContextMenu', 'key': 'ContextMenu'},
+  'NumpadMultiply': {'keyCode': 106, 'code': 'NumpadMultiply', 'key': '*', 'location': 3},
+  'NumpadAdd': {'keyCode': 107, 'code': 'NumpadAdd', 'key': '+', 'location': 3},
+  'NumpadSubtract': {'keyCode': 109, 'code': 'NumpadSubtract', 'key': '-', 'location': 3},
+  'NumpadDivide': {'keyCode': 111, 'code': 'NumpadDivide', 'key': '/', 'location': 3},
+  'F1': {'keyCode': 112, 'code': 'F1', 'key': 'F1'},
+  'F2': {'keyCode': 113, 'code': 'F2', 'key': 'F2'},
+  'F3': {'keyCode': 114, 'code': 'F3', 'key': 'F3'},
+  'F4': {'keyCode': 115, 'code': 'F4', 'key': 'F4'},
+  'F5': {'keyCode': 116, 'code': 'F5', 'key': 'F5'},
+  'F6': {'keyCode': 117, 'code': 'F6', 'key': 'F6'},
+  'F7': {'keyCode': 118, 'code': 'F7', 'key': 'F7'},
+  'F8': {'keyCode': 119, 'code': 'F8', 'key': 'F8'},
+  'F9': {'keyCode': 120, 'code': 'F9', 'key': 'F9'},
+  'F10': {'keyCode': 121, 'code': 'F10', 'key': 'F10'},
+  'F11': {'keyCode': 122, 'code': 'F11', 'key': 'F11'},
+  'F12': {'keyCode': 123, 'code': 'F12', 'key': 'F12'},
+  'F13': {'keyCode': 124, 'code': 'F13', 'key': 'F13'},
+  'F14': {'keyCode': 125, 'code': 'F14', 'key': 'F14'},
+  'F15': {'keyCode': 126, 'code': 'F15', 'key': 'F15'},
+  'F16': {'keyCode': 127, 'code': 'F16', 'key': 'F16'},
+  'F17': {'keyCode': 128, 'code': 'F17', 'key': 'F17'},
+  'F18': {'keyCode': 129, 'code': 'F18', 'key': 'F18'},
+  'F19': {'keyCode': 130, 'code': 'F19', 'key': 'F19'},
+  'F20': {'keyCode': 131, 'code': 'F20', 'key': 'F20'},
+  'F21': {'keyCode': 132, 'code': 'F21', 'key': 'F21'},
+  'F22': {'keyCode': 133, 'code': 'F22', 'key': 'F22'},
+  'F23': {'keyCode': 134, 'code': 'F23', 'key': 'F23'},
+  'F24': {'keyCode': 135, 'code': 'F24', 'key': 'F24'},
+  'NumLock': {'keyCode': 144, 'code': 'NumLock', 'key': 'NumLock'},
+  'ScrollLock': {'keyCode': 145, 'code': 'ScrollLock', 'key': 'ScrollLock'},
+  'AudioVolumeMute': {'keyCode': 173, 'code': 'AudioVolumeMute', 'key': 'AudioVolumeMute'},
+  'AudioVolumeDown': {'keyCode': 174, 'code': 'AudioVolumeDown', 'key': 'AudioVolumeDown'},
+  'AudioVolumeUp': {'keyCode': 175, 'code': 'AudioVolumeUp', 'key': 'AudioVolumeUp'},
+  'MediaTrackNext': {'keyCode': 176, 'code': 'MediaTrackNext', 'key': 'MediaTrackNext'},
+  'MediaTrackPrevious': {'keyCode': 177, 'code': 'MediaTrackPrevious', 'key': 'MediaTrackPrevious'},
+  'MediaStop': {'keyCode': 178, 'code': 'MediaStop', 'key': 'MediaStop'},
+  'MediaPlayPause': {'keyCode': 179, 'code': 'MediaPlayPause', 'key': 'MediaPlayPause'},
+  'Semicolon': {'keyCode': 186, 'code': 'Semicolon', 'shiftKey': ':', 'key': ';'},
+  'Equal': {'keyCode': 187, 'code': 'Equal', 'shiftKey': '+', 'key': '='},
+  'NumpadEqual': {'keyCode': 187, 'code': 'NumpadEqual', 'key': '=', 'location': 3},
+  'Comma': {'keyCode': 188, 'code': 'Comma', 'shiftKey': '\<', 'key': ','},
+  'Minus': {'keyCode': 189, 'code': 'Minus', 'shiftKey': '_', 'key': '-'},
+  'Period': {'keyCode': 190, 'code': 'Period', 'shiftKey': '>', 'key': '.'},
+  'Slash': {'keyCode': 191, 'code': 'Slash', 'shiftKey': '?', 'key': '/'},
+  'Backquote': {'keyCode': 192, 'code': 'Backquote', 'shiftKey': '~', 'key': '`'},
+  'BracketLeft': {'keyCode': 219, 'code': 'BracketLeft', 'shiftKey': '{', 'key': '['},
+  'Backslash': {'keyCode': 220, 'code': 'Backslash', 'shiftKey': '|', 'key': '\\'},
+  'BracketRight': {'keyCode': 221, 'code': 'BracketRight', 'shiftKey': '}', 'key': ']'},
+  'Quote': {'keyCode': 222, 'code': 'Quote', 'shiftKey': '"', 'key': '\''},
+  'AltGraph': {'keyCode': 225, 'code': 'AltGraph', 'key': 'AltGraph'},
+  'Props': {'keyCode': 247, 'code': 'Props', 'key': 'CrSel'},
+  'Cancel': {'keyCode': 3, 'key': 'Cancel', 'code': 'Abort'},
+  'Clear': {'keyCode': 12, 'key': 'Clear', 'code': 'Numpad5', 'location': 3},
+  'Shift': {'keyCode': 16, 'key': 'Shift', 'code': 'ShiftLeft', 'location': 1},
+  'Control': {'keyCode': 17, 'key': 'Control', 'code': 'ControlLeft', 'location': 1},
+  'Alt': {'keyCode': 18, 'key': 'Alt', 'code': 'AltLeft', 'location': 1},
+  'Accept': {'keyCode': 30, 'key': 'Accept'},
+  'ModeChange': {'keyCode': 31, 'key': 'ModeChange'},
+  ' ': {'keyCode': 32, 'key': ' ', 'code': 'Space'},
+  'Print': {'keyCode': 42, 'key': 'Print'},
+  'Execute': {'keyCode': 43, 'key': 'Execute', 'code': 'Open'},
+  '\u0000': {'keyCode': 46, 'key': '\u0000', 'code': 'NumpadDecimal', 'location': 3},
+  'a': {'keyCode': 65, 'key': 'a', 'code': 'KeyA'},
+  'b': {'keyCode': 66, 'key': 'b', 'code': 'KeyB'},
+  'c': {'keyCode': 67, 'key': 'c', 'code': 'KeyC'},
+  'd': {'keyCode': 68, 'key': 'd', 'code': 'KeyD'},
+  'e': {'keyCode': 69, 'key': 'e', 'code': 'KeyE'},
+  'f': {'keyCode': 70, 'key': 'f', 'code': 'KeyF'},
+  'g': {'keyCode': 71, 'key': 'g', 'code': 'KeyG'},
+  'h': {'keyCode': 72, 'key': 'h', 'code': 'KeyH'},
+  'i': {'keyCode': 73, 'key': 'i', 'code': 'KeyI'},
+  'j': {'keyCode': 74, 'key': 'j', 'code': 'KeyJ'},
+  'k': {'keyCode': 75, 'key': 'k', 'code': 'KeyK'},
+  'l': {'keyCode': 76, 'key': 'l', 'code': 'KeyL'},
+  'm': {'keyCode': 77, 'key': 'm', 'code': 'KeyM'},
+  'n': {'keyCode': 78, 'key': 'n', 'code': 'KeyN'},
+  'o': {'keyCode': 79, 'key': 'o', 'code': 'KeyO'},
+  'p': {'keyCode': 80, 'key': 'p', 'code': 'KeyP'},
+  'q': {'keyCode': 81, 'key': 'q', 'code': 'KeyQ'},
+  'r': {'keyCode': 82, 'key': 'r', 'code': 'KeyR'},
+  's': {'keyCode': 83, 'key': 's', 'code': 'KeyS'},
+  't': {'keyCode': 84, 'key': 't', 'code': 'KeyT'},
+  'u': {'keyCode': 85, 'key': 'u', 'code': 'KeyU'},
+  'v': {'keyCode': 86, 'key': 'v', 'code': 'KeyV'},
+  'w': {'keyCode': 87, 'key': 'w', 'code': 'KeyW'},
+  'x': {'keyCode': 88, 'key': 'x', 'code': 'KeyX'},
+  'y': {'keyCode': 89, 'key': 'y', 'code': 'KeyY'},
+  'z': {'keyCode': 90, 'key': 'z', 'code': 'KeyZ'},
+  'Meta': {'keyCode': 91, 'key': 'Meta', 'code': 'MetaLeft', 'location': 1},
+  '*': {'keyCode': 106, 'key': '*', 'code': 'NumpadMultiply', 'location': 3},
+  '+': {'keyCode': 107, 'key': '+', 'code': 'NumpadAdd', 'location': 3},
+  '-': {'keyCode': 109, 'key': '-', 'code': 'NumpadSubtract', 'location': 3},
+  '/': {'keyCode': 111, 'key': '/', 'code': 'NumpadDivide', 'location': 3},
+  ';': {'keyCode': 186, 'key': ';', 'code': 'Semicolon'},
+  '=': {'keyCode': 187, 'key': '=', 'code': 'Equal'},
+  ',': {'keyCode': 188, 'key': ',', 'code': 'Comma'},
+  '.': {'keyCode': 190, 'key': '.', 'code': 'Period'},
+  '`': {'keyCode': 192, 'key': '`', 'code': 'Backquote'},
+  '[': {'keyCode': 219, 'key': '[', 'code': 'BracketLeft'},
+  '\\': {'keyCode': 220, 'key': '\\', 'code': 'Backslash'},
+  ']': {'keyCode': 221, 'key': ']', 'code': 'BracketRight'},
+  '\'': {'keyCode': 222, 'key': '\'', 'code': 'Quote'},
+  'Attn': {'keyCode': 246, 'key': 'Attn'},
+  'CrSel': {'keyCode': 247, 'key': 'CrSel', 'code': 'Props'},
+  'ExSel': {'keyCode': 248, 'key': 'ExSel'},
+  'EraseEof': {'keyCode': 249, 'key': 'EraseEof'},
+  'Play': {'keyCode': 250, 'key': 'Play'},
+  'ZoomOut': {'keyCode': 251, 'key': 'ZoomOut'},
+  ')': {'keyCode': 48, 'key': ')', 'code': 'Digit0'},
+  '!': {'keyCode': 49, 'key': '!', 'code': 'Digit1'},
+  '@': {'keyCode': 50, 'key': '@', 'code': 'Digit2'},
+  '#': {'keyCode': 51, 'key': '#', 'code': 'Digit3'},
+  '$': {'keyCode': 52, 'key': '$', 'code': 'Digit4'},
+  '%': {'keyCode': 53, 'key': '%', 'code': 'Digit5'},
+  '^': {'keyCode': 54, 'key': '^', 'code': 'Digit6'},
+  '&': {'keyCode': 55, 'key': '&', 'code': 'Digit7'},
+  '(': {'keyCode': 57, 'key': '\(', 'code': 'Digit9'},
+  'A': {'keyCode': 65, 'key': 'A', 'code': 'KeyA'},
+  'B': {'keyCode': 66, 'key': 'B', 'code': 'KeyB'},
+  'C': {'keyCode': 67, 'key': 'C', 'code': 'KeyC'},
+  'D': {'keyCode': 68, 'key': 'D', 'code': 'KeyD'},
+  'E': {'keyCode': 69, 'key': 'E', 'code': 'KeyE'},
+  'F': {'keyCode': 70, 'key': 'F', 'code': 'KeyF'},
+  'G': {'keyCode': 71, 'key': 'G', 'code': 'KeyG'},
+  'H': {'keyCode': 72, 'key': 'H', 'code': 'KeyH'},
+  'I': {'keyCode': 73, 'key': 'I', 'code': 'KeyI'},
+  'J': {'keyCode': 74, 'key': 'J', 'code': 'KeyJ'},
+  'K': {'keyCode': 75, 'key': 'K', 'code': 'KeyK'},
+  'L': {'keyCode': 76, 'key': 'L', 'code': 'KeyL'},
+  'M': {'keyCode': 77, 'key': 'M', 'code': 'KeyM'},
+  'N': {'keyCode': 78, 'key': 'N', 'code': 'KeyN'},
+  'O': {'keyCode': 79, 'key': 'O', 'code': 'KeyO'},
+  'P': {'keyCode': 80, 'key': 'P', 'code': 'KeyP'},
+  'Q': {'keyCode': 81, 'key': 'Q', 'code': 'KeyQ'},
+  'R': {'keyCode': 82, 'key': 'R', 'code': 'KeyR'},
+  'S': {'keyCode': 83, 'key': 'S', 'code': 'KeyS'},
+  'T': {'keyCode': 84, 'key': 'T', 'code': 'KeyT'},
+  'U': {'keyCode': 85, 'key': 'U', 'code': 'KeyU'},
+  'V': {'keyCode': 86, 'key': 'V', 'code': 'KeyV'},
+  'W': {'keyCode': 87, 'key': 'W', 'code': 'KeyW'},
+  'X': {'keyCode': 88, 'key': 'X', 'code': 'KeyX'},
+  'Y': {'keyCode': 89, 'key': 'Y', 'code': 'KeyY'},
+  'Z': {'keyCode': 90, 'key': 'Z', 'code': 'KeyZ'},
+  ':': {'keyCode': 186, 'key': ':', 'code': 'Semicolon'},
+  '<': {'keyCode': 188, 'key': '\<', 'code': 'Comma'},
+  '_': {'keyCode': 189, 'key': '_', 'code': 'Minus'},
+  '>': {'keyCode': 190, 'key': '>', 'code': 'Period'},
+  '?': {'keyCode': 191, 'key': '?', 'code': 'Slash'},
+  '~': {'keyCode': 192, 'key': '~', 'code': 'Backquote'},
+  '{': {'keyCode': 219, 'key': '{', 'code': 'BracketLeft'},
+  '|': {'keyCode': 220, 'key': '|', 'code': 'Backslash'},
+  '}': {'keyCode': 221, 'key': '}', 'code': 'BracketRight'},
+  '"': {'keyCode': 222, 'key': '"', 'code': 'Quote'},
+  'SoftLeft': {'key': 'SoftLeft', 'code': 'SoftLeft', 'location': 4},
+  'SoftRight': {'key': 'SoftRight', 'code': 'SoftRight', 'location': 4},
+  'Camera': {'keyCode': 44, 'key': 'Camera', 'code': 'Camera', 'location': 4},
+  'Call': {'key': 'Call', 'code': 'Call', 'location': 4},
+  'EndCall': {'keyCode': 95, 'key': 'EndCall', 'code': 'EndCall', 'location': 4},
+  'VolumeDown': {'keyCode': 182, 'key': 'VolumeDown', 'code': 'VolumeDown', 'location': 4},
+  'VolumeUp': {'keyCode': 183, 'key': 'VolumeUp', 'code': 'VolumeUp', 'location': 4},
+};
--- a/src/api.ts
+++ b/src/api.ts
@ -0,0 +1,88 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+export = {
+  Chromium: {
+    Accessibility: require('./chromium/Accessibility').Accessibility,
+    Browser: require('./chromium/Browser').Browser,
+    BrowserContext: require('./chromium/BrowserContext').BrowserContext,
+    BrowserFetcher: require('./chromium/BrowserFetcher').BrowserFetcher,
+    CDPSession: require('./chromium/Connection').CDPSession,
+    ConsoleMessage: require('./chromium/Page').ConsoleMessage,
+    Coverage: require('./chromium/Coverage').Coverage,
+    Dialog: require('./chromium/Dialog').Dialog,
+    ElementHandle: require('./chromium/JSHandle').ElementHandle,
+    ExecutionContext: require('./chromium/ExecutionContext').ExecutionContext,
+    FileChooser: require('./chromium/Page').FileChooser,
+    Frame: require('./chromium/Frame').Frame,
+    JSHandle: require('./chromium/JSHandle').JSHandle,
+    Keyboard: require('./chromium/Input').Keyboard,
+    Mouse: require('./chromium/Input').Mouse,
+    Page: require('./chromium/Page').Page,
+    Playwright: require('./chromium/Playwright').Playwright,
+    Request: require('./chromium/NetworkManager').Request,
+    Response: require('./chromium/NetworkManager').Response,
+    SecurityDetails: require('./chromium/NetworkManager').SecurityDetails,
+    Target: require('./chromium/Target').Target,
+    TimeoutError: require('./Errors').TimeoutError,
+    Touchscreen: require('./chromium/Input').Touchscreen,
+    Tracing: require('./chromium/Tracing').Tracing,
+    Worker: require('./chromium/Worker').Worker,
+  },
+  Firefox: {
+    Accessibility: require('./firefox/Accessibility').Accessibility,
+    Browser: require('./firefox/Browser').Browser,
+    BrowserContext: require('./firefox/Browser').BrowserContext,
+    BrowserFetcher: require('./firefox/BrowserFetcher').BrowserFetcher,
+    CDPSession: require('./firefox/Connection').CDPSession,
+    ConsoleMessage: require('./firefox/Page').ConsoleMessage,
+    Dialog: require('./firefox/Dialog').Dialog,
+    ElementHandle: require('./firefox/JSHandle').ElementHandle,
+    ExecutionContext: require('./firefox/ExecutionContext').ExecutionContext,
+    FileChooser: require('./firefox/Page').FileChooser,
+    Frame: require('./firefox/FrameManager').Frame,
+    JSHandle: require('./firefox/JSHandle').JSHandle,
+    Keyboard: require('./firefox/Input').Keyboard,
+    Mouse: require('./firefox/Input').Mouse,
+    Page: require('./firefox/Page').Page,
+    Playwright: require('./firefox/Playwright').Playwright,
+    Request: require('./firefox/NetworkManager').Request,
+    Response: require('./firefox/NetworkManager').Response,
+    SecurityDetails: require('./firefox/NetworkManager').SecurityDetails,
+    Target: require('./firefox/Browser').Target,
+    TimeoutError: require('./Errors').TimeoutError,
+    Touchscreen: require('./firefox/Input').Touchscreen,
+  },
+  WebKit: {
+    Browser: require('./webkit/Browser').Browser,
+    BrowserContext: require('./webkit/Browser').BrowserContext,
+    BrowserFetcher: require('./webkit/BrowserFetcher'),
+    ConsoleMessage: require('./webkit/Page').ConsoleMessage,
+    ElementHandle: require('./webkit/JSHandle').ElementHandle,
+    ExecutionContext: require('./webkit/ExecutionContext').ExecutionContext,
+    Frame: require('./webkit/FrameManager').Frame,
+    JSHandle: require('./webkit/JSHandle').JSHandle,
+    Keyboard: require('./webkit/Input').Keyboard,
+    Mouse: require('./webkit/Input').Mouse,
+    Page: require('./webkit/Page').Page,
+    Playwright: require('./webkit/Playwright').Playwright,
+    Request: require('./webkit/NetworkManager').Request,
+    Response: require('./webkit/NetworkManager').Response,
+    Target: require('./webkit/Browser').Target,
+    TimeoutError: require('./Errors').TimeoutError,
+    Touchscreen: require('./webkit/Input').Touchscreen,
+  }
+};
--- a/src/chromium/Accessibility.ts
+++ b/src/chromium/Accessibility.ts
@ -0,0 +1,373 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSession } from './Connection';
+import { ElementHandle } from './JSHandle';
+import { Protocol } from './protocol';
+
+type SerializedAXNode = {
+  role: string,
+  name?: string,
+  value?: string|number,
+  description?: string,
+
+  keyshortcuts?: string,
+  roledescription?: string,
+  valuetext?: string,
+
+  disabled?: boolean,
+  expanded?: boolean,
+  focused?: boolean,
+  modal?: boolean,
+  multiline?: boolean,
+  multiselectable?: boolean,
+  readonly?: boolean,
+  required?: boolean,
+  selected?: boolean,
+
+  checked?: boolean|'mixed',
+  pressed?: boolean|'mixed',
+
+  level?: number,
+  valuemin?: number,
+  valuemax?: number,
+
+  autocomplete?: string,
+  haspopup?: string,
+  invalid?: string,
+  orientation?: string,
+
+  children?: SerializedAXNode[]
+};
+
+export class Accessibility {
+  private _client: CDPSession;
+
+  constructor(client: CDPSession) {
+    this._client = client;
+  }
+
+  async snapshot(options: {
+      interestingOnly?: boolean;
+      root?: ElementHandle | null;
+    } = {}): Promise<SerializedAXNode> {
+    const {
+      interestingOnly = true,
+      root = null,
+    } = options;
+    const {nodes} = await this._client.send('Accessibility.getFullAXTree');
+    let backendNodeId = null;
+    if (root) {
+      const {node} = await this._client.send('DOM.describeNode', {objectId: root._remoteObject.objectId});
+      backendNodeId = node.backendNodeId;
+    }
+    const defaultRoot = AXNode.createTree(nodes);
+    let needle = defaultRoot;
+    if (backendNodeId) {
+      needle = defaultRoot.find(node => node._payload.backendDOMNodeId === backendNodeId);
+      if (!needle)
+        return null;
+    }
+    if (!interestingOnly)
+      return serializeTree(needle)[0];
+
+    const interestingNodes: Set<AXNode> = new Set();
+    collectInterestingNodes(interestingNodes, defaultRoot, false);
+    if (!interestingNodes.has(needle))
+      return null;
+    return serializeTree(needle, interestingNodes)[0];
+  }
+}
+
+function collectInterestingNodes(collection: Set<AXNode>, node: AXNode, insideControl: boolean) {
+  if (node.isInteresting(insideControl))
+    collection.add(node);
+  if (node.isLeafNode())
+    return;
+  insideControl = insideControl || node.isControl();
+  for (const child of node._children)
+    collectInterestingNodes(collection, child, insideControl);
+}
+
+function serializeTree(node: AXNode, whitelistedNodes?: Set<AXNode>): SerializedAXNode[] {
+  const children: SerializedAXNode[] = [];
+  for (const child of node._children)
+    children.push(...serializeTree(child, whitelistedNodes));
+
+  if (whitelistedNodes && !whitelistedNodes.has(node))
+    return children;
+
+  const serializedNode = node.serialize();
+  if (children.length)
+    serializedNode.children = children;
+  return [serializedNode];
+}
+
+
+class AXNode {
+  _payload: Protocol.Accessibility.AXNode;
+  _children: AXNode[] = [];
+  private _richlyEditable = false;
+  private _editable = false;
+  private _focusable = false;
+  private _expanded = false;
+  private _hidden = false;
+  private _name: string;
+  private _role: string;
+  private _cachedHasFocusableChild: boolean | undefined;
+
+  constructor(payload: Protocol.Accessibility.AXNode) {
+    this._payload = payload;
+
+    this._name = this._payload.name ? this._payload.name.value : '';
+    this._role = this._payload.role ? this._payload.role.value : 'Unknown';
+
+    for (const property of this._payload.properties || []) {
+      if (property.name === 'editable') {
+        this._richlyEditable = property.value.value === 'richtext';
+        this._editable = true;
+      }
+      if (property.name === 'focusable')
+        this._focusable = property.value.value;
+      if (property.name === 'expanded')
+        this._expanded = property.value.value;
+      if (property.name === 'hidden')
+        this._hidden = property.value.value;
+    }
+  }
+
+  private _isPlainTextField(): boolean {
+    if (this._richlyEditable)
+      return false;
+    if (this._editable)
+      return true;
+    return this._role === 'textbox' || this._role === 'ComboBox' || this._role === 'searchbox';
+  }
+
+  private _isTextOnlyObject(): boolean {
+    const role = this._role;
+    return (role === 'LineBreak' || role === 'text' ||
+            role === 'InlineTextBox');
+  }
+
+  private _hasFocusableChild(): boolean {
+    if (this._cachedHasFocusableChild === undefined) {
+      this._cachedHasFocusableChild = false;
+      for (const child of this._children) {
+        if (child._focusable || child._hasFocusableChild()) {
+          this._cachedHasFocusableChild = true;
+          break;
+        }
+      }
+    }
+    return this._cachedHasFocusableChild;
+  }
+
+  find(predicate: (arg0: AXNode) => boolean): AXNode | null {
+    if (predicate(this))
+      return this;
+    for (const child of this._children) {
+      const result = child.find(predicate);
+      if (result)
+        return result;
+    }
+    return null;
+  }
+
+  isLeafNode(): boolean {
+    if (!this._children.length)
+      return true;
+
+    // These types of objects may have children that we use as internal
+    // implementation details, but we want to expose them as leaves to platform
+    // accessibility APIs because screen readers might be confused if they find
+    // any children.
+    if (this._isPlainTextField() || this._isTextOnlyObject())
+      return true;
+
+    // Roles whose children are only presentational according to the ARIA and
+    // HTML5 Specs should be hidden from screen readers.
+    // (Note that whilst ARIA buttons can have only presentational children, HTML5
+    // buttons are allowed to have content.)
+    switch (this._role) {
+      case 'doc-cover':
+      case 'graphics-symbol':
+      case 'img':
+      case 'Meter':
+      case 'scrollbar':
+      case 'slider':
+      case 'separator':
+      case 'progressbar':
+        return true;
+      default:
+        break;
+    }
+
+    // Here and below: Android heuristics
+    if (this._hasFocusableChild())
+      return false;
+    if (this._focusable && this._name)
+      return true;
+    if (this._role === 'heading' && this._name)
+      return true;
+    return false;
+  }
+
+  isControl(): boolean {
+    switch (this._role) {
+      case 'button':
+      case 'checkbox':
+      case 'ColorWell':
+      case 'combobox':
+      case 'DisclosureTriangle':
+      case 'listbox':
+      case 'menu':
+      case 'menubar':
+      case 'menuitem':
+      case 'menuitemcheckbox':
+      case 'menuitemradio':
+      case 'radio':
+      case 'scrollbar':
+      case 'searchbox':
+      case 'slider':
+      case 'spinbutton':
+      case 'switch':
+      case 'tab':
+      case 'textbox':
+      case 'tree':
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  isInteresting(insideControl: boolean): boolean {
+    const role = this._role;
+    if (role === 'Ignored' || this._hidden)
+      return false;
+
+    if (this._focusable || this._richlyEditable)
+      return true;
+
+    // If it's not focusable but has a control role, then it's interesting.
+    if (this.isControl())
+      return true;
+
+    // A non focusable child of a control is not interesting
+    if (insideControl)
+      return false;
+
+    return this.isLeafNode() && !!this._name;
+  }
+
+  serialize(): SerializedAXNode {
+    const properties: Map<string, number | string | boolean> = new Map();
+    for (const property of this._payload.properties || [])
+      properties.set(property.name.toLowerCase(), property.value.value);
+    if (this._payload.name)
+      properties.set('name', this._payload.name.value);
+    if (this._payload.value)
+      properties.set('value', this._payload.value.value);
+    if (this._payload.description)
+      properties.set('description', this._payload.description.value);
+
+    const node: {[x in keyof SerializedAXNode]: any} = {
+      role: this._role
+    };
+
+    const userStringProperties: Array<keyof SerializedAXNode> = [
+      'name',
+      'value',
+      'description',
+      'keyshortcuts',
+      'roledescription',
+      'valuetext',
+    ];
+    for (const userStringProperty of userStringProperties) {
+      if (!properties.has(userStringProperty))
+        continue;
+      node[userStringProperty] = properties.get(userStringProperty);
+    }
+
+    const booleanProperties: Array<keyof SerializedAXNode> = [
+      'disabled',
+      'expanded',
+      'focused',
+      'modal',
+      'multiline',
+      'multiselectable',
+      'readonly',
+      'required',
+      'selected',
+    ];
+    for (const booleanProperty of booleanProperties) {
+      // WebArea's treat focus differently than other nodes. They report whether their frame  has focus,
+      // not whether focus is specifically on the root node.
+      if (booleanProperty === 'focused' && this._role === 'WebArea')
+        continue;
+      const value = properties.get(booleanProperty);
+      if (!value)
+        continue;
+      node[booleanProperty] = value;
+    }
+
+    const tristateProperties: Array<keyof SerializedAXNode> = [
+      'checked',
+      'pressed',
+    ];
+    for (const tristateProperty of tristateProperties) {
+      if (!properties.has(tristateProperty))
+        continue;
+      const value = properties.get(tristateProperty);
+      node[tristateProperty] = value === 'mixed' ? 'mixed' : value === 'true' ? true : false;
+    }
+    const numericalProperties: Array<keyof SerializedAXNode> = [
+      'level',
+      'valuemax',
+      'valuemin',
+    ];
+    for (const numericalProperty of numericalProperties) {
+      if (!properties.has(numericalProperty))
+        continue;
+      node[numericalProperty] = properties.get(numericalProperty);
+    }
+    const tokenProperties: Array<keyof SerializedAXNode> = [
+      'autocomplete',
+      'haspopup',
+      'invalid',
+      'orientation',
+    ];
+    for (const tokenProperty of tokenProperties) {
+      const value = properties.get(tokenProperty);
+      if (!value || value === 'false')
+        continue;
+      node[tokenProperty] = value;
+    }
+    return node as SerializedAXNode;
+  }
+
+  static createTree(payloads: Protocol.Accessibility.AXNode[]): AXNode {
+    const nodeById: Map<string, AXNode> = new Map();
+    for (const payload of payloads)
+      nodeById.set(payload.nodeId, new AXNode(payload));
+    for (const node of nodeById.values()) {
+      for (const childId of node._payload.childIds || [])
+        node._children.push(nodeById.get(childId));
+    }
+    return nodeById.values().next().value;
+  }
+}
--- a/src/chromium/Browser.ts
+++ b/src/chromium/Browser.ts
@ -0,0 +1,220 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as childProcess from 'child_process';
+import { EventEmitter } from 'events';
+import { Events } from '../Events';
+import { assert, helper } from '../helper';
+import { BrowserContext } from './BrowserContext';
+import { Connection, ConnectionEvents } from './Connection';
+import { Page, Viewport } from './Page';
+import { Target } from './Target';
+import { TaskQueue } from './TaskQueue';
+import { Protocol } from './protocol';
+
+export class Browser extends EventEmitter {
+  private _ignoreHTTPSErrors: boolean;
+  private _defaultViewport: Viewport;
+  private _process: childProcess.ChildProcess;
+  private _screenshotTaskQueue = new TaskQueue();
+  private _connection: Connection;
+  private _closeCallback: () => Promise<void>;
+  private _defaultContext: BrowserContext;
+  private _contexts = new Map<string, BrowserContext>();
+  _targets = new Map<string, Target>();
+
+  static async create(
+    connection: Connection,
+    contextIds: string[],
+    ignoreHTTPSErrors: boolean,
+    defaultViewport: Viewport | null,
+    process: childProcess.ChildProcess | null,
+    closeCallback?: (() => Promise<void>)) {
+    const browser = new Browser(connection, contextIds, ignoreHTTPSErrors, defaultViewport, process, closeCallback);
+    await connection.send('Target.setDiscoverTargets', {discover: true});
+    return browser;
+  }
+
+  constructor(
+    connection: Connection,
+    contextIds: string[],
+    ignoreHTTPSErrors: boolean,
+    defaultViewport: Viewport | null,
+    process: childProcess.ChildProcess | null,
+    closeCallback?: (() => Promise<void>)) {
+    super();
+    this._ignoreHTTPSErrors = ignoreHTTPSErrors;
+    this._defaultViewport = defaultViewport;
+    this._process = process;
+    this._connection = connection;
+    this._closeCallback = closeCallback || (() => Promise.resolve());
+
+    this._defaultContext = new BrowserContext(this._connection, this, null);
+    for (const contextId of contextIds)
+      this._contexts.set(contextId, new BrowserContext(this._connection, this, contextId));
+
+    this._connection.on(ConnectionEvents.Disconnected, () => this.emit(Events.Browser.Disconnected));
+    this._connection.on('Target.targetCreated', this._targetCreated.bind(this));
+    this._connection.on('Target.targetDestroyed', this._targetDestroyed.bind(this));
+    this._connection.on('Target.targetInfoChanged', this._targetInfoChanged.bind(this));
+  }
+
+  process(): childProcess.ChildProcess | null {
+    return this._process;
+  }
+
+  async createIncognitoBrowserContext(): Promise<BrowserContext> {
+    const {browserContextId} = await this._connection.send('Target.createBrowserContext');
+    const context = new BrowserContext(this._connection, this, browserContextId);
+    this._contexts.set(browserContextId, context);
+    return context;
+  }
+
+  browserContexts(): BrowserContext[] {
+    return [this._defaultContext, ...Array.from(this._contexts.values())];
+  }
+
+  defaultBrowserContext(): BrowserContext {
+    return this._defaultContext;
+  }
+
+  async _disposeContext(contextId: string | null) {
+    await this._connection.send('Target.disposeBrowserContext', {browserContextId: contextId || undefined});
+    this._contexts.delete(contextId);
+  }
+
+  async _targetCreated(event: Protocol.Target.targetCreatedPayload) {
+    const targetInfo = event.targetInfo;
+    const {browserContextId} = targetInfo;
+    const context = (browserContextId && this._contexts.has(browserContextId)) ? this._contexts.get(browserContextId) : this._defaultContext;
+
+    const target = new Target(targetInfo, context, () => this._connection.createSession(targetInfo), this._ignoreHTTPSErrors, this._defaultViewport, this._screenshotTaskQueue);
+    assert(!this._targets.has(event.targetInfo.targetId), 'Target should not exist before targetCreated');
+    this._targets.set(event.targetInfo.targetId, target);
+
+    if (await target._initializedPromise) {
+      this.emit(Events.Browser.TargetCreated, target);
+      context.emit(Events.BrowserContext.TargetCreated, target);
+    }
+  }
+
+  async _targetDestroyed(event: { targetId: string; }) {
+    const target = this._targets.get(event.targetId);
+    target._initializedCallback(false);
+    this._targets.delete(event.targetId);
+    target._closedCallback();
+    if (await target._initializedPromise) {
+      this.emit(Events.Browser.TargetDestroyed, target);
+      target.browserContext().emit(Events.BrowserContext.TargetDestroyed, target);
+    }
+  }
+
+  _targetInfoChanged(event: Protocol.Target.targetInfoChangedPayload) {
+    const target = this._targets.get(event.targetInfo.targetId);
+    assert(target, 'target should exist before targetInfoChanged');
+    const previousURL = target.url();
+    const wasInitialized = target._isInitialized;
+    target._targetInfoChanged(event.targetInfo);
+    if (wasInitialized && previousURL !== target.url()) {
+      this.emit(Events.Browser.TargetChanged, target);
+      target.browserContext().emit(Events.BrowserContext.TargetChanged, target);
+    }
+  }
+
+  wsEndpoint(): string {
+    return this._connection.url();
+  }
+
+  async newPage(): Promise<Page> {
+    return this._defaultContext.newPage();
+  }
+
+  async _createPageInContext(contextId: string | null): Promise<Page> {
+    const {targetId} = await this._connection.send('Target.createTarget', {url: 'about:blank', browserContextId: contextId || undefined});
+    const target = await this._targets.get(targetId);
+    assert(await target._initializedPromise, 'Failed to create target for page');
+    const page = await target.page();
+    return page;
+  }
+
+  targets(): Target[] {
+    return Array.from(this._targets.values()).filter(target => target._isInitialized);
+  }
+
+  target(): Target {
+    return this.targets().find(target => target.type() === 'browser');
+  }
+
+  async waitForTarget(predicate: (arg0: Target) => boolean, options: { timeout?: number; } | undefined = {}): Promise<Target> {
+    const {
+      timeout = 30000
+    } = options;
+    const existingTarget = this.targets().find(predicate);
+    if (existingTarget)
+      return existingTarget;
+    let resolve;
+    const targetPromise = new Promise<Target>(x => resolve = x);
+    this.on(Events.Browser.TargetCreated, check);
+    this.on(Events.Browser.TargetChanged, check);
+    try {
+      if (!timeout)
+        return await targetPromise;
+      return await helper.waitWithTimeout(targetPromise, 'target', timeout);
+    } finally {
+      this.removeListener(Events.Browser.TargetCreated, check);
+      this.removeListener(Events.Browser.TargetChanged, check);
+    }
+
+    function check(target: Target) {
+      if (predicate(target))
+        resolve(target);
+    }
+  }
+
+  async pages(): Promise<Page[]> {
+    const contextPages = await Promise.all(this.browserContexts().map(context => context.pages()));
+    // Flatten array.
+    return contextPages.reduce((acc, x) => acc.concat(x), []);
+  }
+
+  async version(): Promise<string> {
+    const version = await this._getVersion();
+    return version.product;
+  }
+
+  async userAgent(): Promise<string> {
+    const version = await this._getVersion();
+    return version.userAgent;
+  }
+
+  async close() {
+    await this._closeCallback.call(null);
+    this.disconnect();
+  }
+
+  disconnect() {
+    this._connection.dispose();
+  }
+
+  isConnected(): boolean {
+    return !this._connection._closed;
+  }
+
+  _getVersion(): Promise<any> {
+    return this._connection.send('Browser.getVersion');
+  }
+}
--- a/src/chromium/BrowserContext.ts
+++ b/src/chromium/BrowserContext.ts
@ -0,0 +1,103 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { EventEmitter } from 'events';
+import { assert } from '../helper';
+import { Browser } from './Browser';
+import { Connection } from './Connection';
+import { Page } from './Page';
+import { Target } from './Target';
+import { Protocol } from './protocol';
+
+export class BrowserContext extends EventEmitter {
+  private _connection: Connection;
+  private _browser: Browser;
+  private _id: string;
+
+  constructor(connection: Connection, browser: Browser, contextId: string | null) {
+    super();
+    this._connection = connection;
+    this._browser = browser;
+    this._id = contextId;
+  }
+
+  targets(): Target[] {
+    return this._browser.targets().filter(target => target.browserContext() === this);
+  }
+
+  waitForTarget(predicate: (arg0: Target) => boolean, options: { timeout?: number; } | undefined): Promise<Target> {
+    return this._browser.waitForTarget(target => target.browserContext() === this && predicate(target), options);
+  }
+
+  async pages(): Promise<Page[]> {
+    const pages = await Promise.all(
+        this.targets()
+            .filter(target => target.type() === 'page')
+            .map(target => target.page())
+    );
+    return pages.filter(page => !!page);
+  }
+
+  isIncognito(): boolean {
+    return !!this._id;
+  }
+
+  async overridePermissions(origin: string, userPermissions: string[]) {
+    const webPermissionToProtocol = new Map<string, Protocol.Browser.PermissionType>([
+      ['geolocation', 'geolocation'],
+      ['midi', 'midi'],
+      ['notifications', 'notifications'],
+      ['camera', 'videoCapture'],
+      ['microphone', 'audioCapture'],
+      ['background-sync', 'backgroundSync'],
+      ['ambient-light-sensor', 'sensors'],
+      ['accelerometer', 'sensors'],
+      ['gyroscope', 'sensors'],
+      ['magnetometer', 'sensors'],
+      ['accessibility-events', 'accessibilityEvents'],
+      ['clipboard-read', 'clipboardRead'],
+      ['clipboard-write', 'clipboardWrite'],
+      ['payment-handler', 'paymentHandler'],
+      // chrome-specific permissions we have.
+      ['midi-sysex', 'midiSysex'],
+    ]);
+    const permissions = userPermissions.map(permission => {
+      const protocolPermission = webPermissionToProtocol.get(permission);
+      if (!protocolPermission)
+        throw new Error('Unknown permission: ' + permission);
+      return protocolPermission;
+    });
+    await this._connection.send('Browser.grantPermissions', {origin, browserContextId: this._id || undefined, permissions});
+  }
+
+  async clearPermissionOverrides() {
+    await this._connection.send('Browser.resetPermissions', {browserContextId: this._id || undefined});
+  }
+
+  newPage(): Promise<Page> {
+    return this._browser._createPageInContext(this._id);
+  }
+
+  browser(): Browser {
+    return this._browser;
+  }
+
+  async close() {
+    assert(this._id, 'Non-incognito profiles cannot be closed!');
+    await this._browser._disposeContext(this._id);
+  }
+}
--- a/src/chromium/BrowserFetcher.ts
+++ b/src/chromium/BrowserFetcher.ts
@ -0,0 +1,261 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as extract from 'extract-zip';
+import * as fs from 'fs';
+import * as ProxyAgent from 'https-proxy-agent';
+import * as os from 'os';
+import * as path from 'path';
+// @ts-ignore
+import { getProxyForUrl } from 'proxy-from-env';
+import * as removeRecursive from 'rimraf';
+import * as URL from 'url';
+import * as util from 'util';
+import { assert, helper } from '../helper';
+
+const DEFAULT_DOWNLOAD_HOST = 'https://storage.googleapis.com';
+
+const supportedPlatforms = ['mac', 'linux', 'win32', 'win64'];
+const downloadURLs = {
+  linux: '%s/chromium-browser-snapshots/Linux_x64/%d/%s.zip',
+  mac: '%s/chromium-browser-snapshots/Mac/%d/%s.zip',
+  win32: '%s/chromium-browser-snapshots/Win/%d/%s.zip',
+  win64: '%s/chromium-browser-snapshots/Win_x64/%d/%s.zip',
+};
+
+function archiveName(platform: string, revision: string): string {
+  if (platform === 'linux')
+    return 'chrome-linux';
+  if (platform === 'mac')
+    return 'chrome-mac';
+  if (platform === 'win32' || platform === 'win64') {
+    // Windows archive name changed at r591479.
+    return parseInt(revision, 10) > 591479 ? 'chrome-win' : 'chrome-win32';
+  }
+  return null;
+}
+
+function downloadURL(platform: string, host: string, revision: string): string {
+  return util.format(downloadURLs[platform], host, revision, archiveName(platform, revision));
+}
+
+const readdirAsync = helper.promisify(fs.readdir.bind(fs));
+const mkdirAsync = helper.promisify(fs.mkdir.bind(fs));
+const unlinkAsync = helper.promisify(fs.unlink.bind(fs));
+const chmodAsync = helper.promisify(fs.chmod.bind(fs));
+
+function existsAsync(filePath) {
+  let fulfill = null;
+  const promise = new Promise(x => fulfill = x);
+  fs.access(filePath, err => fulfill(!err));
+  return promise;
+}
+
+export class BrowserFetcher {
+  private _downloadsFolder: string;
+  private _downloadHost: string;
+  private _platform: string;
+
+  constructor(projectRoot: string, options: BrowserFetcherOptions = {}) {
+    this._downloadsFolder = options.path || path.join(projectRoot, '.local-chromium');
+    this._downloadHost = options.host || DEFAULT_DOWNLOAD_HOST;
+    this._platform = options.platform || '';
+    if (!this._platform) {
+      const platform = os.platform();
+      if (platform === 'darwin')
+        this._platform = 'mac';
+      else if (platform === 'linux')
+        this._platform = 'linux';
+      else if (platform === 'win32')
+        this._platform = os.arch() === 'x64' ? 'win64' : 'win32';
+      assert(this._platform, 'Unsupported platform: ' + os.platform());
+    }
+    assert(supportedPlatforms.includes(this._platform), 'Unsupported platform: ' + this._platform);
+  }
+
+  platform(): string {
+    return this._platform;
+  }
+
+  canDownload(revision: string): Promise<boolean> {
+    const url = downloadURL(this._platform, this._downloadHost, revision);
+    let resolve;
+    const promise = new Promise<boolean>(x => resolve = x);
+    const request = httpRequest(url, 'HEAD', response => {
+      resolve(response.statusCode === 200);
+    });
+    request.on('error', error => {
+      console.error(error);
+      resolve(false);
+    });
+    return promise;
+  }
+  async download(revision: string, progressCallback: ((arg0: number, arg1: number) => void) | null): Promise<BrowserFetcherRevisionInfo> {
+    const url = downloadURL(this._platform, this._downloadHost, revision);
+    const zipPath = path.join(this._downloadsFolder, `download-${this._platform}-${revision}.zip`);
+    const folderPath = this._getFolderPath(revision);
+    if (await existsAsync(folderPath))
+      return this.revisionInfo(revision);
+    if (!(await existsAsync(this._downloadsFolder)))
+      await mkdirAsync(this._downloadsFolder);
+    try {
+      await downloadFile(url, zipPath, progressCallback);
+      await extractZip(zipPath, folderPath);
+    } finally {
+      if (await existsAsync(zipPath))
+        await unlinkAsync(zipPath);
+    }
+    const revisionInfo = this.revisionInfo(revision);
+    if (revisionInfo)
+      await chmodAsync(revisionInfo.executablePath, 0o755);
+    return revisionInfo;
+  }
+
+  async localRevisions(): Promise<string[]> {
+    if (!await existsAsync(this._downloadsFolder))
+      return [];
+    const fileNames = await readdirAsync(this._downloadsFolder);
+    return fileNames.map(fileName => parseFolderPath(fileName)).filter(entry => entry && entry.platform === this._platform).map(entry => entry.revision);
+  }
+
+  async remove(revision: string) {
+    const folderPath = this._getFolderPath(revision);
+    assert(await existsAsync(folderPath), `Failed to remove: revision ${revision} is not downloaded`);
+    await new Promise(fulfill => removeRecursive(folderPath, fulfill));
+  }
+
+  revisionInfo(revision: string): BrowserFetcherRevisionInfo {
+    const folderPath = this._getFolderPath(revision);
+    let executablePath = '';
+    if (this._platform === 'mac')
+      executablePath = path.join(folderPath, archiveName(this._platform, revision), 'Chromium.app', 'Contents', 'MacOS', 'Chromium');
+    else if (this._platform === 'linux')
+      executablePath = path.join(folderPath, archiveName(this._platform, revision), 'chrome');
+    else if (this._platform === 'win32' || this._platform === 'win64')
+      executablePath = path.join(folderPath, archiveName(this._platform, revision), 'chrome.exe');
+    else
+      throw new Error('Unsupported platform: ' + this._platform);
+    const url = downloadURL(this._platform, this._downloadHost, revision);
+    const local = fs.existsSync(folderPath);
+    return {revision, executablePath, folderPath, local, url};
+  }
+
+  _getFolderPath(revision: string): string {
+    return path.join(this._downloadsFolder, this._platform + '-' + revision);
+  }
+}
+
+function parseFolderPath(folderPath: string): { platform: string; revision: string; } | null {
+  const name = path.basename(folderPath);
+  const splits = name.split('-');
+  if (splits.length !== 2)
+    return null;
+  const [platform, revision] = splits;
+  if (!supportedPlatforms.includes(platform))
+    return null;
+  return {platform, revision};
+}
+
+function downloadFile(url: string, destinationPath: string, progressCallback: ((arg0: number, arg1: number) => void) | null): Promise<any> {
+  let fulfill, reject;
+  let downloadedBytes = 0;
+  let totalBytes = 0;
+
+  const promise = new Promise((x, y) => { fulfill = x; reject = y; });
+
+  const request = httpRequest(url, 'GET', response => {
+    if (response.statusCode !== 200) {
+      const error = new Error(`Download failed: server returned code ${response.statusCode}. URL: ${url}`);
+      // consume response data to free up memory
+      response.resume();
+      reject(error);
+      return;
+    }
+    const file = fs.createWriteStream(destinationPath);
+    file.on('finish', () => fulfill());
+    file.on('error', error => reject(error));
+    response.pipe(file);
+    totalBytes = parseInt(response.headers['content-length'], 10);
+    if (progressCallback)
+      response.on('data', onData);
+  });
+  request.on('error', error => reject(error));
+  return promise;
+
+  function onData(chunk) {
+    downloadedBytes += chunk.length;
+    progressCallback(downloadedBytes, totalBytes);
+  }
+}
+
+function extractZip(zipPath: string, folderPath: string): Promise<Error | null> {
+  return new Promise((fulfill, reject) => extract(zipPath, {dir: folderPath}, err => {
+    if (err)
+      reject(err);
+    else
+      fulfill();
+  }));
+}
+
+function httpRequest(url: string, method: string, response: (r: any) => void) {
+  let options: any = URL.parse(url);
+  options.method = method;
+
+  const proxyURL = getProxyForUrl(url);
+  if (proxyURL) {
+    if (url.startsWith('http:')) {
+      const proxy = URL.parse(proxyURL);
+      options = {
+        path: options.href,
+        host: proxy.hostname,
+        port: proxy.port,
+      };
+    } else {
+      const parsedProxyURL: any = URL.parse(proxyURL);
+      parsedProxyURL.secureProxy = parsedProxyURL.protocol === 'https:';
+
+      options.agent = new ProxyAgent(parsedProxyURL);
+      options.rejectUnauthorized = false;
+    }
+  }
+
+  const requestCallback = res => {
+    if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location)
+      httpRequest(res.headers.location, method, response);
+    else
+      response(res);
+  };
+  const request = options.protocol === 'https:' ?
+    require('https').request(options, requestCallback) :
+    require('http').request(options, requestCallback);
+  request.end();
+  return request;
+}
+
+export type BrowserFetcherOptions = {
+  platform?: string,
+  path?: string,
+  host ?: string,
+};
+
+type BrowserFetcherRevisionInfo = {
+  folderPath: string,
+  executablePath: string,
+  url: string,
+  local: boolean,
+  revision: string,
+};
--- a/src/chromium/Connection.ts
+++ b/src/chromium/Connection.ts
@ -0,0 +1,219 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {assert} from '../helper';
+import {Events} from '../Events';
+import * as debug from 'debug';
+import {EventEmitter} from 'events';
+import { ConnectionTransport } from '../ConnectionTransport';
+import { Protocol } from './protocol';
+
+const debugProtocol = debug('playwright:protocol');
+
+export const ConnectionEvents = {
+  Disconnected: Symbol('ConnectionEvents.Disconnected')
+};
+
+export class Connection extends EventEmitter {
+  private _url: string;
+  private _lastId = 0;
+  private _callbacks = new Map<number, {resolve:(o: any) => void, reject:  (e: Error) => void, error: Error, method: string}>();
+  private _delay: number;
+  private _transport: ConnectionTransport;
+  private _sessions = new Map<string, CDPSession>();
+  _closed = false;
+  on: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  addListener: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  off: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  removeListener: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  once: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+
+  constructor(url: string, transport: ConnectionTransport, delay: number | undefined = 0) {
+    super();
+    this._url = url;
+    this._delay = delay;
+
+    this._transport = transport;
+    this._transport.onmessage = this._onMessage.bind(this);
+    this._transport.onclose = this._onClose.bind(this);
+  }
+
+  static fromSession(session: CDPSession): Connection {
+    return session._connection;
+  }
+
+  session(sessionId: string): CDPSession | null {
+    return this._sessions.get(sessionId) || null;
+  }
+
+  url(): string {
+    return this._url;
+  }
+
+  send<T extends keyof Protocol.CommandParameters>(
+    method: T,
+    params?: Protocol.CommandParameters[T]
+  ): Promise<Protocol.CommandReturnValues[T]> {
+    const id = this._rawSend({method, params});
+    return new Promise((resolve, reject) => {
+      this._callbacks.set(id, {resolve, reject, error: new Error(), method});
+    });
+  }
+
+  _rawSend(message: any): number {
+    const id = ++this._lastId;
+    message = JSON.stringify(Object.assign({}, message, {id}));
+    debugProtocol('SEND ► ' + message);
+    this._transport.send(message);
+    return id;
+  }
+
+  async _onMessage(message: string) {
+    if (this._delay)
+      await new Promise(f => setTimeout(f, this._delay));
+    debugProtocol('◀ RECV ' + message);
+    const object = JSON.parse(message);
+    if (object.method === 'Target.attachedToTarget') {
+      const sessionId = object.params.sessionId;
+      const session = new CDPSession(this, object.params.targetInfo.type, sessionId);
+      this._sessions.set(sessionId, session);
+    } else if (object.method === 'Target.detachedFromTarget') {
+      const session = this._sessions.get(object.params.sessionId);
+      if (session) {
+        session._onClosed();
+        this._sessions.delete(object.params.sessionId);
+      }
+    }
+    if (object.sessionId) {
+      const session = this._sessions.get(object.sessionId);
+      if (session)
+        session._onMessage(object);
+    } else if (object.id) {
+      const callback = this._callbacks.get(object.id);
+      // Callbacks could be all rejected if someone has called `.dispose()`.
+      if (callback) {
+        this._callbacks.delete(object.id);
+        if (object.error)
+          callback.reject(createProtocolError(callback.error, callback.method, object));
+        else
+          callback.resolve(object.result);
+      }
+    } else {
+      this.emit(object.method, object.params);
+    }
+  }
+
+  _onClose() {
+    if (this._closed)
+      return;
+    this._closed = true;
+    this._transport.onmessage = null;
+    this._transport.onclose = null;
+    for (const callback of this._callbacks.values())
+      callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
+    this._callbacks.clear();
+    for (const session of this._sessions.values())
+      session._onClosed();
+    this._sessions.clear();
+    this.emit(ConnectionEvents.Disconnected);
+  }
+
+  dispose() {
+    this._onClose();
+    this._transport.close();
+  }
+
+  async createSession(targetInfo: Protocol.Target.TargetInfo): Promise<CDPSession> {
+    const {sessionId} = await this.send('Target.attachToTarget', {targetId: targetInfo.targetId, flatten: true});
+    return this._sessions.get(sessionId);
+  }
+}
+
+export const CDPSessionEvents = {
+  Disconnected: Symbol('Events.CDPSession.Disconnected')
+};
+
+export class CDPSession extends EventEmitter {
+  _connection: Connection;
+  private _callbacks = new Map<number, {resolve:(o: any) => void, reject: (e: Error) => void, error: Error, method: string}>();
+  private _targetType: string;
+  private _sessionId: string;
+  on: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  addListener: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  off: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  removeListener: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+  once: <T extends keyof Protocol.Events | symbol>(event: T, listener: (payload: T extends symbol ? any : Protocol.Events[T extends keyof Protocol.Events ? T : never]) => void) => this;
+
+  constructor(connection: Connection, targetType: string, sessionId: string) {
+    super();
+    this._connection = connection;
+    this._targetType = targetType;
+    this._sessionId = sessionId;
+  }
+
+  send<T extends keyof Protocol.CommandParameters>(
+    method: T,
+    params?: Protocol.CommandParameters[T]
+  ): Promise<Protocol.CommandReturnValues[T]> {
+    if (!this._connection)
+      return Promise.reject(new Error(`Protocol error (${method}): Session closed. Most likely the ${this._targetType} has been closed.`));
+    const id = this._connection._rawSend({sessionId: this._sessionId, method, params});
+    return new Promise((resolve, reject) => {
+      this._callbacks.set(id, {resolve, reject, error: new Error(), method});
+    });
+  }
+
+  _onMessage(object: { id?: number; method: string; params: any; error: { message: string; data: any; }; result?: any; }) {
+    if (object.id && this._callbacks.has(object.id)) {
+      const callback = this._callbacks.get(object.id);
+      this._callbacks.delete(object.id);
+      if (object.error)
+        callback.reject(createProtocolError(callback.error, callback.method, object));
+      else
+        callback.resolve(object.result);
+    } else {
+      assert(!object.id);
+      this.emit(object.method, object.params);
+    }
+  }
+
+  async detach() {
+    if (!this._connection)
+      throw new Error(`Session already detached. Most likely the ${this._targetType} has been closed.`);
+    await this._connection.send('Target.detachFromTarget',  {sessionId: this._sessionId});
+  }
+
+  _onClosed() {
+    for (const callback of this._callbacks.values())
+      callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
+    this._callbacks.clear();
+    this._connection = null;
+    this.emit(CDPSessionEvents.Disconnected);
+  }
+}
+
+function createProtocolError(error: Error, method: string, object: { error: { message: string; data: any; }; }): Error {
+  let message = `Protocol error (${method}): ${object.error.message}`;
+  if ('data' in object.error)
+    message += ` ${object.error.data}`;
+  return rewriteError(error, message);
+}
+
+function rewriteError(error: Error, message: string): Error {
+  error.message = message;
+  return error;
+}
--- a/src/chromium/Coverage.ts
+++ b/src/chromium/Coverage.ts
@ -0,0 +1,298 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSession } from './Connection';
+import { assert, debugError, helper, RegisteredListener } from '../helper';
+import { Protocol } from './protocol';
+
+const {EVALUATION_SCRIPT_URL} = require('./ExecutionContext');
+
+type CoverageEntry = {
+  url: string,
+  text: string,
+  ranges : {start: number, end: number}[]
+};
+
+export class Coverage {
+  private _jsCoverage: JSCoverage;
+  private _cssCoverage: CSSCoverage;
+
+  constructor(client: CDPSession) {
+    this._jsCoverage = new JSCoverage(client);
+    this._cssCoverage = new CSSCoverage(client);
+  }
+
+  async startJSCoverage(options: {
+      resetOnNavigation?: boolean;
+      reportAnonymousScripts?: boolean;
+    }) {
+    return await this._jsCoverage.start(options);
+  }
+
+  async stopJSCoverage(): Promise<CoverageEntry[]> {
+    return await this._jsCoverage.stop();
+  }
+
+  async startCSSCoverage(options: { resetOnNavigation?: boolean; } = {}) {
+    return await this._cssCoverage.start(options);
+  }
+
+  async stopCSSCoverage(): Promise<CoverageEntry[]> {
+    return await this._cssCoverage.stop();
+  }
+}
+
+module.exports = {Coverage};
+
+class JSCoverage {
+  _client: CDPSession;
+  _enabled: boolean;
+  _scriptURLs: Map<string, string>;
+  _scriptSources: Map<string, string>;
+  _eventListeners: RegisteredListener[];
+  _resetOnNavigation: boolean;
+  _reportAnonymousScripts: boolean;
+
+  constructor(client: CDPSession) {
+    this._client = client;
+    this._enabled = false;
+    this._scriptURLs = new Map();
+    this._scriptSources = new Map();
+    this._eventListeners = [];
+    this._resetOnNavigation = false;
+  }
+
+  async start(options: {
+      resetOnNavigation?: boolean;
+      reportAnonymousScripts?: boolean;
+    } = {}) {
+    assert(!this._enabled, 'JSCoverage is already enabled');
+    const {
+      resetOnNavigation = true,
+      reportAnonymousScripts = false
+    } = options;
+    this._resetOnNavigation = resetOnNavigation;
+    this._reportAnonymousScripts = reportAnonymousScripts;
+    this._enabled = true;
+    this._scriptURLs.clear();
+    this._scriptSources.clear();
+    this._eventListeners = [
+      helper.addEventListener(this._client, 'Debugger.scriptParsed', this._onScriptParsed.bind(this)),
+      helper.addEventListener(this._client, 'Runtime.executionContextsCleared', this._onExecutionContextsCleared.bind(this)),
+    ];
+    await Promise.all([
+      this._client.send('Profiler.enable'),
+      this._client.send('Profiler.startPreciseCoverage', {callCount: false, detailed: true}),
+      this._client.send('Debugger.enable'),
+      this._client.send('Debugger.setSkipAllPauses', {skip: true})
+    ]);
+  }
+
+  _onExecutionContextsCleared() {
+    if (!this._resetOnNavigation)
+      return;
+    this._scriptURLs.clear();
+    this._scriptSources.clear();
+  }
+
+  async _onScriptParsed(event: Protocol.Debugger.scriptParsedPayload) {
+    // Ignore playwright-injected scripts
+    if (event.url === EVALUATION_SCRIPT_URL)
+      return;
+    // Ignore other anonymous scripts unless the reportAnonymousScripts option is true.
+    if (!event.url && !this._reportAnonymousScripts)
+      return;
+    try {
+      const response = await this._client.send('Debugger.getScriptSource', {scriptId: event.scriptId});
+      this._scriptURLs.set(event.scriptId, event.url);
+      this._scriptSources.set(event.scriptId, response.scriptSource);
+    } catch (e) {
+      // This might happen if the page has already navigated away.
+      debugError(e);
+    }
+  }
+
+  async stop(): Promise<CoverageEntry[]> {
+    assert(this._enabled, 'JSCoverage is not enabled');
+    this._enabled = false;
+    const [profileResponse] = await Promise.all([
+      this._client.send('Profiler.takePreciseCoverage'),
+      this._client.send('Profiler.stopPreciseCoverage'),
+      this._client.send('Profiler.disable'),
+      this._client.send('Debugger.disable'),
+    ]);
+    helper.removeEventListeners(this._eventListeners);
+
+    const coverage = [];
+    for (const entry of profileResponse.result) {
+      let url = this._scriptURLs.get(entry.scriptId);
+      if (!url && this._reportAnonymousScripts)
+        url = 'debugger://VM' + entry.scriptId;
+      const text = this._scriptSources.get(entry.scriptId);
+      if (text === undefined || url === undefined)
+        continue;
+      const flattenRanges = [];
+      for (const func of entry.functions)
+        flattenRanges.push(...func.ranges);
+      const ranges = convertToDisjointRanges(flattenRanges);
+      coverage.push({url, ranges, text});
+    }
+    return coverage;
+  }
+}
+
+class CSSCoverage {
+  _client: CDPSession;
+  _enabled: boolean;
+  _stylesheetURLs: Map<string, string>;
+  _stylesheetSources: Map<string, string>;
+  _eventListeners: RegisteredListener[];
+  _resetOnNavigation: boolean;
+
+  constructor(client: CDPSession) {
+    this._client = client;
+    this._enabled = false;
+    this._stylesheetURLs = new Map();
+    this._stylesheetSources = new Map();
+    this._eventListeners = [];
+    this._resetOnNavigation = false;
+  }
+
+  async start(options: { resetOnNavigation?: boolean; } = {}) {
+    assert(!this._enabled, 'CSSCoverage is already enabled');
+    const {resetOnNavigation = true} = options;
+    this._resetOnNavigation = resetOnNavigation;
+    this._enabled = true;
+    this._stylesheetURLs.clear();
+    this._stylesheetSources.clear();
+    this._eventListeners = [
+      helper.addEventListener(this._client, 'CSS.styleSheetAdded', this._onStyleSheet.bind(this)),
+      helper.addEventListener(this._client, 'Runtime.executionContextsCleared', this._onExecutionContextsCleared.bind(this)),
+    ];
+    await Promise.all([
+      this._client.send('DOM.enable'),
+      this._client.send('CSS.enable'),
+      this._client.send('CSS.startRuleUsageTracking'),
+    ]);
+  }
+
+  _onExecutionContextsCleared() {
+    if (!this._resetOnNavigation)
+      return;
+    this._stylesheetURLs.clear();
+    this._stylesheetSources.clear();
+  }
+
+  async _onStyleSheet(event: Protocol.CSS.styleSheetAddedPayload) {
+    const header = event.header;
+    // Ignore anonymous scripts
+    if (!header.sourceURL)
+      return;
+    try {
+      const response = await this._client.send('CSS.getStyleSheetText', {styleSheetId: header.styleSheetId});
+      this._stylesheetURLs.set(header.styleSheetId, header.sourceURL);
+      this._stylesheetSources.set(header.styleSheetId, response.text);
+    } catch (e) {
+      // This might happen if the page has already navigated away.
+      debugError(e);
+    }
+  }
+
+  async stop(): Promise<CoverageEntry[]> {
+    assert(this._enabled, 'CSSCoverage is not enabled');
+    this._enabled = false;
+    const ruleTrackingResponse = await this._client.send('CSS.stopRuleUsageTracking');
+    await Promise.all([
+      this._client.send('CSS.disable'),
+      this._client.send('DOM.disable'),
+    ]);
+    helper.removeEventListeners(this._eventListeners);
+
+    // aggregate by styleSheetId
+    const styleSheetIdToCoverage = new Map();
+    for (const entry of ruleTrackingResponse.ruleUsage) {
+      let ranges = styleSheetIdToCoverage.get(entry.styleSheetId);
+      if (!ranges) {
+        ranges = [];
+        styleSheetIdToCoverage.set(entry.styleSheetId, ranges);
+      }
+      ranges.push({
+        startOffset: entry.startOffset,
+        endOffset: entry.endOffset,
+        count: entry.used ? 1 : 0,
+      });
+    }
+
+    const coverage = [];
+    for (const styleSheetId of this._stylesheetURLs.keys()) {
+      const url = this._stylesheetURLs.get(styleSheetId);
+      const text = this._stylesheetSources.get(styleSheetId);
+      const ranges = convertToDisjointRanges(styleSheetIdToCoverage.get(styleSheetId) || []);
+      coverage.push({url, ranges, text});
+    }
+
+    return coverage;
+  }
+}
+
+function convertToDisjointRanges(nestedRanges: {
+    startOffset: number;
+    endOffset: number;
+    count: number; }[]): { start: number; end: number; }[] {
+  const points = [];
+  for (const range of nestedRanges) {
+    points.push({ offset: range.startOffset, type: 0, range });
+    points.push({ offset: range.endOffset, type: 1, range });
+  }
+  // Sort points to form a valid parenthesis sequence.
+  points.sort((a, b) => {
+    // Sort with increasing offsets.
+    if (a.offset !== b.offset)
+      return a.offset - b.offset;
+    // All "end" points should go before "start" points.
+    if (a.type !== b.type)
+      return b.type - a.type;
+    const aLength = a.range.endOffset - a.range.startOffset;
+    const bLength = b.range.endOffset - b.range.startOffset;
+    // For two "start" points, the one with longer range goes first.
+    if (a.type === 0)
+      return bLength - aLength;
+    // For two "end" points, the one with shorter range goes first.
+    return aLength - bLength;
+  });
+
+  const hitCountStack = [];
+  const results = [];
+  let lastOffset = 0;
+  // Run scanning line to intersect all ranges.
+  for (const point of points) {
+    if (hitCountStack.length && lastOffset < point.offset && hitCountStack[hitCountStack.length - 1] > 0) {
+      const lastResult = results.length ? results[results.length - 1] : null;
+      if (lastResult && lastResult.end === lastOffset)
+        lastResult.end = point.offset;
+      else
+        results.push({start: lastOffset, end: point.offset});
+    }
+    lastOffset = point.offset;
+    if (point.type === 0)
+      hitCountStack.push(point.range.count);
+    else
+      hitCountStack.pop();
+  }
+  // Filter out empty ranges.
+  return results.filter(range => range.end - range.start > 1);
+}
--- a/src/chromium/DOMWorld.ts
+++ b/src/chromium/DOMWorld.ts
@ -0,0 +1,580 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as fs from 'fs';
+import { TimeoutError } from '../Errors';
+import { ExecutionContext } from './ExecutionContext';
+import { Frame } from './Frame';
+import { FrameManager } from './FrameManager';
+import { assert, helper } from '../helper';
+import { ElementHandle, JSHandle, ClickOptions, PointerActionOptions, MultiClickOptions } from './JSHandle';
+import { LifecycleWatcher } from './LifecycleWatcher';
+import { TimeoutSettings } from '../TimeoutSettings';
+const readFileAsync = helper.promisify(fs.readFile);
+
+export class DOMWorld {
+  private _frameManager: FrameManager;
+  private _frame: Frame;
+  private _timeoutSettings: TimeoutSettings;
+  private _documentPromise: Promise<ElementHandle> | null = null;
+  private _contextPromise: Promise<ExecutionContext>;
+  private _contextResolveCallback: ((c: ExecutionContext) => void) | null;
+  _waitTasks = new Set<WaitTask>();
+  private _detached = false;
+
+  constructor(frameManager: FrameManager, frame: Frame, timeoutSettings: TimeoutSettings) {
+    this._frameManager = frameManager;
+    this._frame = frame;
+    this._timeoutSettings = timeoutSettings;
+    this._contextPromise;
+    this._setContext(null);
+  }
+
+  frame(): Frame {
+    return this._frame;
+  }
+
+  _setContext(context: ExecutionContext | null) {
+    if (context) {
+      this._contextResolveCallback.call(null, context);
+      this._contextResolveCallback = null;
+      for (const waitTask of this._waitTasks)
+        waitTask.rerun();
+    } else {
+      this._documentPromise = null;
+      this._contextPromise = new Promise(fulfill => {
+        this._contextResolveCallback = fulfill;
+      });
+    }
+  }
+
+  _hasContext(): boolean {
+    return !this._contextResolveCallback;
+  }
+
+  _detach() {
+    this._detached = true;
+    for (const waitTask of this._waitTasks)
+      waitTask.terminate(new Error('waitForFunction failed: frame got detached.'));
+  }
+
+  executionContext(): Promise<ExecutionContext> {
+    if (this._detached)
+      throw new Error(`Execution Context is not available in detached frame "${this._frame.url()}" (are you trying to evaluate?)`);
+    return this._contextPromise;
+  }
+
+  async evaluateHandle(pageFunction: Function | string, ...args: any[]): Promise<JSHandle> {
+    const context = await this.executionContext();
+    return context.evaluateHandle(pageFunction, ...args);
+  }
+
+  async evaluate(pageFunction: Function | string, ...args: any[]): Promise<any> {
+    const context = await this.executionContext();
+    return context.evaluate(pageFunction, ...args);
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    const document = await this._document();
+    const value = await document.$(selector);
+    return value;
+  }
+
+  async _document(): Promise<ElementHandle> {
+    if (this._documentPromise)
+      return this._documentPromise;
+    this._documentPromise = this.executionContext().then(async context => {
+      const document = await context.evaluateHandle('document');
+      return document.asElement();
+    });
+    return this._documentPromise;
+  }
+
+  async $x(expression: string): Promise<ElementHandle[]> {
+    const document = await this._document();
+    const value = await document.$x(expression);
+    return value;
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: any[]): Promise<any> {
+    const document = await this._document();
+    return document.$eval(selector, pageFunction, ...args);
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: any[]): Promise<any> {
+    const document = await this._document();
+    const value = await document.$$eval(selector, pageFunction, ...args);
+    return value;
+  }
+
+  async $$(selector: string): Promise<ElementHandle[]> {
+    const document = await this._document();
+    const value = await document.$$(selector);
+    return value;
+  }
+
+  async content(): Promise<string> {
+    return await this.evaluate(() => {
+      let retVal = '';
+      if (document.doctype)
+        retVal = new XMLSerializer().serializeToString(document.doctype);
+      if (document.documentElement)
+        retVal += document.documentElement.outerHTML;
+      return retVal;
+    });
+  }
+
+  async setContent(html: string, options: {
+      timeout?: number;
+      waitUntil?: string | string[];
+    } = {}) {
+    const {
+      waitUntil = ['load'],
+      timeout = this._timeoutSettings.navigationTimeout(),
+    } = options;
+    // We rely upon the fact that document.open() will reset frame lifecycle with "init"
+    // lifecycle event. @see https://crrev.com/608658
+    await this.evaluate(html => {
+      document.open();
+      document.write(html);
+      document.close();
+    }, html);
+    const watcher = new LifecycleWatcher(this._frameManager, this._frame, waitUntil, timeout);
+    const error = await Promise.race([
+      watcher.timeoutOrTerminationPromise(),
+      watcher.lifecyclePromise(),
+    ]);
+    watcher.dispose();
+    if (error)
+      throw error;
+  }
+
+  async addScriptTag(options: {
+      url?: string; path?: string;
+      content?: string;
+      type?: string;
+    }): Promise<ElementHandle> {
+    const {
+      url = null,
+      path = null,
+      content = null,
+      type = ''
+    } = options;
+    if (url !== null) {
+      try {
+        const context = await this.executionContext();
+        return (await context.evaluateHandle(addScriptUrl, url, type)).asElement();
+      } catch (error) {
+        throw new Error(`Loading script from ${url} failed`);
+      }
+    }
+
+    if (path !== null) {
+      let contents = await readFileAsync(path, 'utf8');
+      contents += '//# sourceURL=' + path.replace(/\n/g, '');
+      const context = await this.executionContext();
+      return (await context.evaluateHandle(addScriptContent, contents, type)).asElement();
+    }
+
+    if (content !== null) {
+      const context = await this.executionContext();
+      return (await context.evaluateHandle(addScriptContent, content, type)).asElement();
+    }
+
+    throw new Error('Provide an object with a `url`, `path` or `content` property');
+
+    async function addScriptUrl(url: string, type: string): Promise<HTMLElement> {
+      const script = document.createElement('script');
+      script.src = url;
+      if (type)
+        script.type = type;
+      const promise = new Promise((res, rej) => {
+        script.onload = res;
+        script.onerror = rej;
+      });
+      document.head.appendChild(script);
+      await promise;
+      return script;
+    }
+
+    function addScriptContent(content: string, type: string = 'text/javascript'): HTMLElement {
+      const script = document.createElement('script');
+      script.type = type;
+      script.text = content;
+      let error = null;
+      script.onerror = e => error = e;
+      document.head.appendChild(script);
+      if (error)
+        throw error;
+      return script;
+    }
+  }
+
+  async addStyleTag(options: { url?: string; path?: string; content?: string; }): Promise<ElementHandle> {
+    const {
+      url = null,
+      path = null,
+      content = null
+    } = options;
+    if (url !== null) {
+      try {
+        const context = await this.executionContext();
+        return (await context.evaluateHandle(addStyleUrl, url)).asElement();
+      } catch (error) {
+        throw new Error(`Loading style from ${url} failed`);
+      }
+    }
+
+    if (path !== null) {
+      let contents = await readFileAsync(path, 'utf8');
+      contents += '/*# sourceURL=' + path.replace(/\n/g, '') + '*/';
+      const context = await this.executionContext();
+      return (await context.evaluateHandle(addStyleContent, contents)).asElement();
+    }
+
+    if (content !== null) {
+      const context = await this.executionContext();
+      return (await context.evaluateHandle(addStyleContent, content)).asElement();
+    }
+
+    throw new Error('Provide an object with a `url`, `path` or `content` property');
+
+    async function addStyleUrl(url: string): Promise<HTMLElement> {
+      const link = document.createElement('link');
+      link.rel = 'stylesheet';
+      link.href = url;
+      const promise = new Promise((res, rej) => {
+        link.onload = res;
+        link.onerror = rej;
+      });
+      document.head.appendChild(link);
+      await promise;
+      return link;
+    }
+
+    async function addStyleContent(content: string): Promise<HTMLElement> {
+      const style = document.createElement('style');
+      style.type = 'text/css';
+      style.appendChild(document.createTextNode(content));
+      const promise = new Promise((res, rej) => {
+        style.onload = res;
+        style.onerror = rej;
+      });
+      document.head.appendChild(style);
+      await promise;
+      return style;
+    }
+  }
+
+  async click(selector: string, options?: ClickOptions) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.click(options);
+    await handle.dispose();
+  }
+
+  async dblclick(selector: string, options?: MultiClickOptions) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.dblclick(options);
+    await handle.dispose();
+  }
+
+  async tripleclick(selector: string, options?: MultiClickOptions) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.tripleclick(options);
+    await handle.dispose();
+  }
+
+  async fill(selector: string, value: string) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.fill(value);
+    await handle.dispose();
+  }
+
+  async focus(selector: string) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.focus();
+    await handle.dispose();
+  }
+
+  async hover(selector: string, options?: PointerActionOptions) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.hover(options);
+    await handle.dispose();
+  }
+
+  async select(selector: string, ...values: string[]): Promise<string[]> {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    const result = await handle.select(...values);
+    await handle.dispose();
+    return result;
+  }
+
+  async tap(selector: string, options?: PointerActionOptions) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.tap(options);
+    await handle.dispose();
+  }
+
+  async type(selector: string, text: string, options: { delay: (number | undefined); } | undefined) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.type(text, options);
+    await handle.dispose();
+  }
+
+  waitForSelector(selector: string, options: { visible?: boolean; hidden?: boolean; timeout?: number; } | undefined): Promise<ElementHandle | null> {
+    return this._waitForSelectorOrXPath(selector, false, options);
+  }
+
+  waitForXPath(xpath: string, options: { visible?: boolean; hidden?: boolean; timeout?: number; } | undefined): Promise<ElementHandle | null> {
+    return this._waitForSelectorOrXPath(xpath, true, options);
+  }
+
+  waitForFunction(pageFunction: Function | string, options: { polling?: string | number; timeout?: number; } = {}, ...args): Promise<JSHandle> {
+    const {
+      polling = 'raf',
+      timeout = this._timeoutSettings.timeout(),
+    } = options;
+    return new WaitTask(this, pageFunction, 'function', polling, timeout, ...args).promise;
+  }
+
+  async title(): Promise<string> {
+    return this.evaluate(() => document.title);
+  }
+
+  async _waitForSelectorOrXPath(
+    selectorOrXPath: string,
+    isXPath: boolean,
+    options: { visible?: boolean; hidden?: boolean; timeout?: number; } = {}): Promise<ElementHandle | null> {
+    const {
+      visible: waitForVisible = false,
+      hidden: waitForHidden = false,
+      timeout = this._timeoutSettings.timeout(),
+    } = options;
+    const polling = waitForVisible || waitForHidden ? 'raf' : 'mutation';
+    const title = `${isXPath ? 'XPath' : 'selector'} "${selectorOrXPath}"${waitForHidden ? ' to be hidden' : ''}`;
+    const waitTask = new WaitTask(this, predicate, title, polling, timeout, selectorOrXPath, isXPath, waitForVisible, waitForHidden);
+    const handle = await waitTask.promise;
+    if (!handle.asElement()) {
+      await handle.dispose();
+      return null;
+    }
+    return handle.asElement();
+
+    function predicate(selectorOrXPath: string, isXPath: boolean, waitForVisible: boolean, waitForHidden: boolean): (Node | boolean) | null {
+      const node = isXPath
+        ? document.evaluate(selectorOrXPath, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue
+        : document.querySelector(selectorOrXPath);
+      if (!node)
+        return waitForHidden;
+      if (!waitForVisible && !waitForHidden)
+        return node;
+      const element = (node.nodeType === Node.TEXT_NODE ? node.parentElement : node) as Element;
+      const style = window.getComputedStyle(element);
+      const isVisible = style && style.visibility !== 'hidden' && hasVisibleBoundingBox();
+      const success = (waitForVisible === isVisible || waitForHidden === !isVisible);
+      return success ? node : null;
+
+      function hasVisibleBoundingBox(): boolean {
+        const rect = element.getBoundingClientRect();
+        return !!(rect.top || rect.bottom || rect.width || rect.height);
+      }
+    }
+  }
+}
+
+class WaitTask {
+  promise: Promise<JSHandle>;
+  _domWorld: DOMWorld;
+  _polling: string | number;
+  _timeout: number;
+  _predicateBody: string;
+  _args: any[];
+  _runCount: number;
+  _resolve: (result: JSHandle) => void;
+  _reject: (reason: Error) => void;
+  _timeoutTimer: NodeJS.Timer;
+  _terminated: boolean;
+  _runningTask: any;
+
+  constructor(domWorld: DOMWorld, predicateBody: Function | string, title, polling: string | number, timeout: number, ...args: any[]) {
+    if (helper.isString(polling))
+      assert(polling === 'raf' || polling === 'mutation', 'Unknown polling option: ' + polling);
+    else if (helper.isNumber(polling))
+      assert(polling > 0, 'Cannot poll with non-positive interval: ' + polling);
+    else
+      throw new Error('Unknown polling options: ' + polling);
+
+    this._domWorld = domWorld;
+    this._polling = polling;
+    this._timeout = timeout;
+    this._predicateBody = helper.isString(predicateBody) ? 'return (' + predicateBody + ')' : 'return (' + predicateBody + ')(...args)';
+    this._args = args;
+    this._runCount = 0;
+    domWorld._waitTasks.add(this);
+    this.promise = new Promise<JSHandle>((resolve, reject) => {
+      this._resolve = resolve;
+      this._reject = reject;
+    });
+    // Since page navigation requires us to re-install the pageScript, we should track
+    // timeout on our end.
+    if (timeout) {
+      const timeoutError = new TimeoutError(`waiting for ${title} failed: timeout ${timeout}ms exceeded`);
+      this._timeoutTimer = setTimeout(() => this.terminate(timeoutError), timeout);
+    }
+    this.rerun();
+  }
+
+  terminate(error: Error) {
+    this._terminated = true;
+    this._reject(error);
+    this._cleanup();
+  }
+
+  async rerun() {
+    const runCount = ++this._runCount;
+    let success: JSHandle | null = null;
+    let error = null;
+    try {
+      success = await (await this._domWorld.executionContext()).evaluateHandle(waitForPredicatePageFunction, this._predicateBody, this._polling, this._timeout, ...this._args);
+    } catch (e) {
+      error = e;
+    }
+
+    if (this._terminated || runCount !== this._runCount) {
+      if (success)
+        await success.dispose();
+      return;
+    }
+
+    // Ignore timeouts in pageScript - we track timeouts ourselves.
+    // If the frame's execution context has already changed, `frame.evaluate` will
+    // throw an error - ignore this predicate run altogether.
+    if (!error && await this._domWorld.evaluate(s => !s, success).catch(e => true)) {
+      await success.dispose();
+      return;
+    }
+
+    // When the page is navigated, the promise is rejected.
+    // We will try again in the new execution context.
+    if (error && error.message.includes('Execution context was destroyed'))
+      return;
+
+    // We could have tried to evaluate in a context which was already
+    // destroyed.
+    if (error && error.message.includes('Cannot find context with specified id'))
+      return;
+
+    if (error)
+      this._reject(error);
+    else
+      this._resolve(success);
+
+    this._cleanup();
+  }
+
+  _cleanup() {
+    clearTimeout(this._timeoutTimer);
+    this._domWorld._waitTasks.delete(this);
+    this._runningTask = null;
+  }
+}
+
+async function waitForPredicatePageFunction(predicateBody: string, polling: string, timeout: number, ...args): Promise<any> {
+  const predicate = new Function('...args', predicateBody);
+  let timedOut = false;
+  if (timeout)
+    setTimeout(() => timedOut = true, timeout);
+  if (polling === 'raf')
+    return await pollRaf();
+  if (polling === 'mutation')
+    return await pollMutation();
+  if (typeof polling === 'number')
+    return await pollInterval(polling);
+
+  function pollMutation(): Promise<any> {
+    const success = predicate.apply(null, args);
+    if (success)
+      return Promise.resolve(success);
+
+    let fulfill;
+    const result = new Promise(x => fulfill = x);
+    const observer = new MutationObserver(mutations => {
+      if (timedOut) {
+        observer.disconnect();
+        fulfill();
+      }
+      const success = predicate.apply(null, args);
+      if (success) {
+        observer.disconnect();
+        fulfill(success);
+      }
+    });
+    observer.observe(document, {
+      childList: true,
+      subtree: true,
+      attributes: true
+    });
+    return result;
+  }
+
+  function pollRaf(): Promise<any> {
+    let fulfill;
+    const result = new Promise(x => fulfill = x);
+    onRaf();
+    return result;
+
+    function onRaf() {
+      if (timedOut) {
+        fulfill();
+        return;
+      }
+      const success = predicate.apply(null, args);
+      if (success)
+        fulfill(success);
+      else
+        requestAnimationFrame(onRaf);
+    }
+  }
+
+  function pollInterval(pollInterval: number): Promise<any> {
+    let fulfill;
+    const result = new Promise(x => fulfill = x);
+    onTimeout();
+    return result;
+
+    function onTimeout() {
+      if (timedOut) {
+        fulfill();
+        return;
+      }
+      const success = predicate.apply(null, args);
+      if (success)
+        fulfill(success);
+      else
+        setTimeout(onTimeout, pollInterval);
+    }
+  }
+}
--- a/src/chromium/Dialog.ts
+++ b/src/chromium/Dialog.ts
@ -0,0 +1,70 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSession } from './Connection';
+import { assert } from '../helper';
+
+export class Dialog {
+  private _client: CDPSession;
+  private _type: string;
+  private _message: string;
+  private _handled = false;
+  private _defaultValue: string;
+
+  constructor(client: CDPSession, type: string, message: string, defaultValue: (string | undefined) = '') {
+    this._client = client;
+    this._type = type;
+    this._message = message;
+    this._defaultValue = defaultValue;
+  }
+
+  type(): string {
+    return this._type;
+  }
+
+  message(): string {
+    return this._message;
+  }
+
+  defaultValue(): string {
+    return this._defaultValue;
+  }
+
+  async accept(promptText: string | undefined) {
+    assert(!this._handled, 'Cannot accept dialog which is already handled!');
+    this._handled = true;
+    await this._client.send('Page.handleJavaScriptDialog', {
+      accept: true,
+      promptText: promptText
+    });
+  }
+
+  async dismiss() {
+    assert(!this._handled, 'Cannot dismiss dialog which is already handled!');
+    this._handled = true;
+    await this._client.send('Page.handleJavaScriptDialog', {
+      accept: false
+    });
+  }
+}
+
+export const DialogType = {
+  Alert: 'alert',
+  BeforeUnload: 'beforeunload',
+  Confirm: 'confirm',
+  Prompt: 'prompt'
+};
--- a/src/chromium/EmulationManager.ts
+++ b/src/chromium/EmulationManager.ts
@ -0,0 +1,51 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSession } from './Connection';
+import { Viewport } from './Page';
+import { Protocol } from './protocol';
+
+export class EmulationManager {
+  private _client: CDPSession;
+  private _emulatingMobile = false;
+  private _hasTouch = false;
+
+  constructor(client: CDPSession) {
+    this._client = client;
+  }
+
+  async emulateViewport(viewport: Viewport): Promise<boolean> {
+    const mobile = viewport.isMobile || false;
+    const width = viewport.width;
+    const height = viewport.height;
+    const deviceScaleFactor = viewport.deviceScaleFactor || 1;
+    const screenOrientation: Protocol.Emulation.ScreenOrientation = viewport.isLandscape ? { angle: 90, type: 'landscapePrimary' } : { angle: 0, type: 'portraitPrimary' };
+    const hasTouch = viewport.hasTouch || false;
+
+    await Promise.all([
+      this._client.send('Emulation.setDeviceMetricsOverride', { mobile, width, height, deviceScaleFactor, screenOrientation }),
+      this._client.send('Emulation.setTouchEmulationEnabled', {
+        enabled: hasTouch
+      })
+    ]);
+
+    const reloadNeeded = this._emulatingMobile !== mobile || this._hasTouch !== hasTouch;
+    this._emulatingMobile = mobile;
+    this._hasTouch = hasTouch;
+    return reloadNeeded;
+  }
+}
--- a/src/chromium/ExecutionContext.ts
+++ b/src/chromium/ExecutionContext.ts
@ -0,0 +1,171 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSession } from './Connection';
+import { DOMWorld } from './DOMWorld';
+import { Frame } from './Frame';
+import { assert, helper } from '../helper';
+import { valueFromRemoteObject, getExceptionMessage } from './protocolHelper';
+import { createJSHandle, ElementHandle, JSHandle } from './JSHandle';
+import { Protocol } from './protocol';
+
+
+export const EVALUATION_SCRIPT_URL = '__playwright_evaluation_script__';
+const SOURCE_URL_REGEX = /^[\040\t]*\/\/[@#] sourceURL=\s*(\S*?)\s*$/m;
+
+export class ExecutionContext {
+  _client: CDPSession;
+  _world: DOMWorld;
+  private _contextId: number;
+
+  constructor(client: CDPSession, contextPayload: Protocol.Runtime.ExecutionContextDescription, world: DOMWorld | null) {
+    this._client = client;
+    this._world = world;
+    this._contextId = contextPayload.id;
+  }
+
+  frame(): Frame | null {
+    return this._world ? this._world.frame() : null;
+  }
+
+  async evaluate(pageFunction: Function | string, ...args: any[]): Promise<any> {
+    return await this._evaluateInternal(true /* returnByValue */, pageFunction, ...args);
+  }
+
+  async evaluateHandle(pageFunction: Function | string, ...args: any[]): Promise<JSHandle> {
+    return this._evaluateInternal(false /* returnByValue */, pageFunction, ...args);
+  }
+
+  async _evaluateInternal(returnByValue: boolean, pageFunction: Function | string, ...args: any[]): Promise<any> {
+    const suffix = `//# sourceURL=${EVALUATION_SCRIPT_URL}`;
+
+    if (helper.isString(pageFunction)) {
+      const contextId = this._contextId;
+      const expression: string = pageFunction as string;
+      const expressionWithSourceUrl = SOURCE_URL_REGEX.test(expression) ? expression : expression + '\n' + suffix;
+      const {exceptionDetails, result: remoteObject} = await this._client.send('Runtime.evaluate', {
+        expression: expressionWithSourceUrl,
+        contextId,
+        returnByValue,
+        awaitPromise: true,
+        userGesture: true
+      }).catch(rewriteError);
+      if (exceptionDetails)
+        throw new Error('Evaluation failed: ' + getExceptionMessage(exceptionDetails));
+      return returnByValue ? valueFromRemoteObject(remoteObject) : createJSHandle(this, remoteObject);
+    }
+
+    if (typeof pageFunction !== 'function')
+      throw new Error(`Expected to get |string| or |function| as the first argument, but got "${pageFunction}" instead.`);
+
+    let functionText = pageFunction.toString();
+    try {
+      new Function('(' + functionText + ')');
+    } catch (e1) {
+      // This means we might have a function shorthand. Try another
+      // time prefixing 'function '.
+      if (functionText.startsWith('async '))
+        functionText = 'async function ' + functionText.substring('async '.length);
+      else
+        functionText = 'function ' + functionText;
+      try {
+        new Function('(' + functionText  + ')');
+      } catch (e2) {
+        // We tried hard to serialize, but there's a weird beast here.
+        throw new Error('Passed function is not well-serializable!');
+      }
+    }
+    let callFunctionOnPromise;
+    try {
+      callFunctionOnPromise = this._client.send('Runtime.callFunctionOn', {
+        functionDeclaration: functionText + '\n' + suffix + '\n',
+        executionContextId: this._contextId,
+        arguments: args.map(convertArgument.bind(this)),
+        returnByValue,
+        awaitPromise: true,
+        userGesture: true
+      });
+    } catch (err) {
+      if (err instanceof TypeError && err.message.startsWith('Converting circular structure to JSON'))
+        err.message += ' Are you passing a nested JSHandle?';
+      throw err;
+    }
+    const { exceptionDetails, result: remoteObject } = await callFunctionOnPromise.catch(rewriteError);
+    if (exceptionDetails)
+      throw new Error('Evaluation failed: ' + getExceptionMessage(exceptionDetails));
+    return returnByValue ? valueFromRemoteObject(remoteObject) : createJSHandle(this, remoteObject);
+
+    function convertArgument(arg: any): any {
+      if (typeof arg === 'bigint') // eslint-disable-line valid-typeof
+        return { unserializableValue: `${arg.toString()}n` };
+      if (Object.is(arg, -0))
+        return { unserializableValue: '-0' };
+      if (Object.is(arg, Infinity))
+        return { unserializableValue: 'Infinity' };
+      if (Object.is(arg, -Infinity))
+        return { unserializableValue: '-Infinity' };
+      if (Object.is(arg, NaN))
+        return { unserializableValue: 'NaN' };
+      const objectHandle = arg && (arg instanceof JSHandle) ? arg : null;
+      if (objectHandle) {
+        if (objectHandle._context !== this)
+          throw new Error('JSHandles can be evaluated only in the context they were created!');
+        if (objectHandle._disposed)
+          throw new Error('JSHandle is disposed!');
+        if (objectHandle._remoteObject.unserializableValue)
+          return { unserializableValue: objectHandle._remoteObject.unserializableValue };
+        if (!objectHandle._remoteObject.objectId)
+          return { value: objectHandle._remoteObject.value };
+        return { objectId: objectHandle._remoteObject.objectId };
+      }
+      return { value: arg };
+    }
+
+    function rewriteError(error: Error): Protocol.Runtime.evaluateReturnValue {
+      if (error.message.includes('Object reference chain is too long'))
+        return {result: {type: 'undefined'}};
+      if (error.message.includes('Object couldn\'t be returned by value'))
+        return {result: {type: 'undefined'}};
+
+      if (error.message.endsWith('Cannot find context with specified id') || error.message.endsWith('Inspected target navigated or closed'))
+        throw new Error('Execution context was destroyed, most likely because of a navigation.');
+      throw error;
+    }
+  }
+
+  async queryObjects(prototypeHandle: JSHandle): Promise<JSHandle> {
+    assert(!prototypeHandle._disposed, 'Prototype JSHandle is disposed!');
+    assert(prototypeHandle._remoteObject.objectId, 'Prototype JSHandle must not be referencing primitive value');
+    const response = await this._client.send('Runtime.queryObjects', {
+      prototypeObjectId: prototypeHandle._remoteObject.objectId
+    });
+    return createJSHandle(this, response.objects);
+  }
+
+  async _adoptElementHandle(elementHandle: ElementHandle): Promise<ElementHandle> {
+    assert(elementHandle.executionContext() !== this, 'Cannot adopt handle that already belongs to this execution context');
+    assert(this._world, 'Cannot adopt handle without DOMWorld');
+    const nodeInfo = await this._client.send('DOM.describeNode', {
+      objectId: elementHandle._remoteObject.objectId,
+    });
+    const {object} = await this._client.send('DOM.resolveNode', {
+      backendNodeId: nodeInfo.node.backendNodeId,
+      executionContextId: this._contextId,
+    });
+    return createJSHandle(this, object) as ElementHandle;
+  }
+}
--- a/src/chromium/Frame.ts
+++ b/src/chromium/Frame.ts
@ -0,0 +1,264 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { helper } from '../helper';
+import { CDPSession } from './Connection';
+import { DOMWorld } from './DOMWorld';
+import { ExecutionContext } from './ExecutionContext';
+import { FrameManager } from './FrameManager';
+import { ClickOptions, ElementHandle, JSHandle, MultiClickOptions, PointerActionOptions } from './JSHandle';
+import { Response } from './NetworkManager';
+import { Protocol } from './protocol';
+
+export class Frame {
+  _id: string;
+  _frameManager: FrameManager;
+  private _client: CDPSession;
+  private _parentFrame: Frame;
+  private _url = '';
+  private _detached = false;
+  _loaderId = '';
+  _lifecycleEvents = new Set<string>();
+  _mainWorld: DOMWorld;
+  _secondaryWorld: DOMWorld;
+  private _childFrames = new Set<Frame>();
+  private _name: string;
+  private _navigationURL: string;
+
+  constructor(frameManager: FrameManager, client: CDPSession, parentFrame: Frame | null, frameId: string) {
+    this._frameManager = frameManager;
+    this._client = client;
+    this._parentFrame = parentFrame;
+    this._id = frameId;
+
+    this._mainWorld = new DOMWorld(frameManager, this, frameManager._timeoutSettings);
+    this._secondaryWorld = new DOMWorld(frameManager, this, frameManager._timeoutSettings);
+
+    if (this._parentFrame)
+      this._parentFrame._childFrames.add(this);
+  }
+
+  async goto(
+    url: string,
+    options: { referer?: string; timeout?: number; waitUntil?: string | string[]; } | undefined
+  ): Promise<Response | null> {
+    return await this._frameManager.navigateFrame(this, url, options);
+  }
+
+  async waitForNavigation(options: { timeout?: number; waitUntil?: string | string[]; } | undefined): Promise<Response | null> {
+    return await this._frameManager.waitForFrameNavigation(this, options);
+  }
+
+  executionContext(): Promise<ExecutionContext> {
+    return this._mainWorld.executionContext();
+  }
+
+  async evaluateHandle(pageFunction: Function | string, ...args: any[]): Promise<JSHandle> {
+    return this._mainWorld.evaluateHandle(pageFunction, ...args);
+  }
+
+  async evaluate(pageFunction: Function | string, ...args: any[]): Promise<any> {
+    return this._mainWorld.evaluate(pageFunction, ...args);
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    return this._mainWorld.$(selector);
+  }
+
+  async $x(expression: string): Promise<ElementHandle[]> {
+    return this._mainWorld.$x(expression);
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: any[]): Promise<(object | undefined)> {
+    return this._mainWorld.$eval(selector, pageFunction, ...args);
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: any[]): Promise<(object | undefined)> {
+    return this._mainWorld.$$eval(selector, pageFunction, ...args);
+  }
+
+  async $$(selector: string): Promise<ElementHandle[]> {
+    return this._mainWorld.$$(selector);
+  }
+
+  async content(): Promise<string> {
+    return this._secondaryWorld.content();
+  }
+
+  async setContent(html: string, options: {
+      timeout?: number;
+      waitUntil?: string | string[];
+    } = {}) {
+    return this._secondaryWorld.setContent(html, options);
+  }
+
+  name(): string {
+    return this._name || '';
+  }
+
+  url(): string {
+    return this._url;
+  }
+
+  parentFrame(): Frame | null {
+    return this._parentFrame;
+  }
+
+  childFrames(): Frame[] {
+    return Array.from(this._childFrames);
+  }
+
+  isDetached(): boolean {
+    return this._detached;
+  }
+
+  async addScriptTag(options: {
+      url?: string; path?: string;
+      content?: string;
+      type?: string; }): Promise<ElementHandle> {
+    return this._mainWorld.addScriptTag(options);
+  }
+
+  async addStyleTag(options: {
+      url?: string;
+      path?: string;
+      content?: string; }): Promise<ElementHandle> {
+    return this._mainWorld.addStyleTag(options);
+  }
+
+  async click(selector: string, options?: ClickOptions) {
+    return this._secondaryWorld.click(selector, options);
+  }
+
+  async dblclick(selector: string, options?: MultiClickOptions) {
+    return this._secondaryWorld.dblclick(selector, options);
+  }
+
+  async tripleclick(selector: string, options?: MultiClickOptions) {
+    return this._secondaryWorld.tripleclick(selector, options);
+  }
+
+  async fill(selector: string, value: string) {
+    return this._secondaryWorld.fill(selector, value);
+  }
+
+  async focus(selector: string) {
+    return this._secondaryWorld.focus(selector);
+  }
+
+  async hover(selector: string, options?: PointerActionOptions) {
+    return this._secondaryWorld.hover(selector, options);
+  }
+
+  select(selector: string, ...values: string[]): Promise<string[]>{
+    return this._secondaryWorld.select(selector, ...values);
+  }
+
+  async tap(selector: string, options?: PointerActionOptions) {
+    return this._secondaryWorld.tap(selector, options);
+  }
+
+  async type(selector: string, text: string, options: { delay: (number | undefined); } | undefined) {
+    return this._mainWorld.type(selector, text, options);
+  }
+
+  waitFor(selectorOrFunctionOrTimeout: (string | number | Function), options: any = {}, ...args: any[]): Promise<JSHandle | null> {
+    const xPathPattern = '//';
+
+    if (helper.isString(selectorOrFunctionOrTimeout)) {
+      const string = selectorOrFunctionOrTimeout as string;
+      if (string.startsWith(xPathPattern))
+        return this.waitForXPath(string, options);
+      return this.waitForSelector(string, options);
+    }
+    if (helper.isNumber(selectorOrFunctionOrTimeout))
+      return new Promise(fulfill => setTimeout(fulfill, selectorOrFunctionOrTimeout as number));
+    if (typeof selectorOrFunctionOrTimeout === 'function')
+      return this.waitForFunction(selectorOrFunctionOrTimeout, options, ...args);
+    return Promise.reject(new Error('Unsupported target type: ' + (typeof selectorOrFunctionOrTimeout)));
+  }
+
+  async waitForSelector(selector: string, options: {
+      visible?: boolean;
+      hidden?: boolean;
+      timeout?: number; } | undefined): Promise<ElementHandle | null> {
+    const handle = await this._secondaryWorld.waitForSelector(selector, options);
+    if (!handle)
+      return null;
+    const mainExecutionContext = await this._mainWorld.executionContext();
+    const result = await mainExecutionContext._adoptElementHandle(handle);
+    await handle.dispose();
+    return result;
+  }
+
+  async waitForXPath(xpath: string, options: {
+      visible?: boolean;
+      hidden?: boolean;
+      timeout?: number; } | undefined): Promise<ElementHandle | null> {
+    const handle = await this._secondaryWorld.waitForXPath(xpath, options);
+    if (!handle)
+      return null;
+    const mainExecutionContext = await this._mainWorld.executionContext();
+    const result = await mainExecutionContext._adoptElementHandle(handle);
+    await handle.dispose();
+    return result;
+  }
+
+  waitForFunction(
+    pageFunction: Function | string,
+    options: { polling?: string | number; timeout?: number; } = {},
+    ...args): Promise<JSHandle> {
+    return this._mainWorld.waitForFunction(pageFunction, options, ...args);
+  }
+
+  async title(): Promise<string> {
+    return this._secondaryWorld.title();
+  }
+
+  _navigated(framePayload: Protocol.Page.Frame) {
+    this._name = framePayload.name;
+    // TODO(lushnikov): remove this once requestInterception has loaderId exposed.
+    this._navigationURL = framePayload.url;
+    this._url = framePayload.url;
+  }
+
+  _navigatedWithinDocument(url: string) {
+    this._url = url;
+  }
+
+  _onLifecycleEvent(loaderId: string, name: string) {
+    if (name === 'init') {
+      this._loaderId = loaderId;
+      this._lifecycleEvents.clear();
+    }
+    this._lifecycleEvents.add(name);
+  }
+
+  _onLoadingStopped() {
+    this._lifecycleEvents.add('DOMContentLoaded');
+    this._lifecycleEvents.add('load');
+  }
+
+  _detach() {
+    this._detached = true;
+    this._mainWorld._detach();
+    this._secondaryWorld._detach();
+    if (this._parentFrame)
+      this._parentFrame._childFrames.delete(this);
+    this._parentFrame = null;
+  }
+}
--- a/src/chromium/FrameManager.ts
+++ b/src/chromium/FrameManager.ts
@ -0,0 +1,316 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { EventEmitter } from 'events';
+import { assert, debugError } from '../helper';
+import { TimeoutSettings } from '../TimeoutSettings';
+import { CDPSession } from './Connection';
+import { EVALUATION_SCRIPT_URL, ExecutionContext } from './ExecutionContext';
+import { Frame } from './Frame';
+import { LifecycleWatcher } from './LifecycleWatcher';
+import { NetworkManager, Response } from './NetworkManager';
+import { Page } from './Page';
+import { Protocol } from './protocol';
+
+const UTILITY_WORLD_NAME = '__playwright_utility_world__';
+
+export const FrameManagerEvents = {
+  FrameAttached: Symbol('Events.FrameManager.FrameAttached'),
+  FrameNavigated: Symbol('Events.FrameManager.FrameNavigated'),
+  FrameDetached: Symbol('Events.FrameManager.FrameDetached'),
+  LifecycleEvent: Symbol('Events.FrameManager.LifecycleEvent'),
+  FrameNavigatedWithinDocument: Symbol('Events.FrameManager.FrameNavigatedWithinDocument'),
+};
+
+export class FrameManager extends EventEmitter {
+  _client: CDPSession;
+  private _page: Page;
+  private _networkManager: NetworkManager;
+  _timeoutSettings: TimeoutSettings;
+  private _frames = new Map<string, Frame>();
+  private _contextIdToContext = new Map<number, ExecutionContext>();
+  private _isolatedWorlds = new Set<string>();
+  private _mainFrame: Frame;
+
+  constructor(client: CDPSession, page: Page, ignoreHTTPSErrors: boolean, timeoutSettings: TimeoutSettings) {
+    super();
+    this._client = client;
+    this._page = page;
+    this._networkManager = new NetworkManager(client, ignoreHTTPSErrors, this);
+    this._timeoutSettings = timeoutSettings;
+
+    this._client.on('Page.frameAttached', event => this._onFrameAttached(event.frameId, event.parentFrameId));
+    this._client.on('Page.frameNavigated', event => this._onFrameNavigated(event.frame));
+    this._client.on('Page.navigatedWithinDocument', event => this._onFrameNavigatedWithinDocument(event.frameId, event.url));
+    this._client.on('Page.frameDetached', event => this._onFrameDetached(event.frameId));
+    this._client.on('Page.frameStoppedLoading', event => this._onFrameStoppedLoading(event.frameId));
+    this._client.on('Runtime.executionContextCreated', event => this._onExecutionContextCreated(event.context));
+    this._client.on('Runtime.executionContextDestroyed', event => this._onExecutionContextDestroyed(event.executionContextId));
+    this._client.on('Runtime.executionContextsCleared', event => this._onExecutionContextsCleared());
+    this._client.on('Page.lifecycleEvent', event => this._onLifecycleEvent(event));
+  }
+
+  async initialize() {
+    const [,{frameTree}] = await Promise.all([
+      this._client.send('Page.enable'),
+      this._client.send('Page.getFrameTree'),
+    ]);
+    this._handleFrameTree(frameTree);
+    await Promise.all([
+      this._client.send('Page.setLifecycleEventsEnabled', { enabled: true }),
+      this._client.send('Runtime.enable', {}).then(() => this._ensureIsolatedWorld(UTILITY_WORLD_NAME)),
+      this._networkManager.initialize(),
+    ]);
+  }
+
+  networkManager(): NetworkManager {
+    return this._networkManager;
+  }
+
+  async navigateFrame(
+    frame: Frame,
+    url: string,
+    options: { referer?: string; timeout?: number; waitUntil?: string | string[]; } = {}): Promise<Response | null> {
+    assertNoLegacyNavigationOptions(options);
+    const {
+      referer = this._networkManager.extraHTTPHeaders()['referer'],
+      waitUntil = ['load'],
+      timeout = this._timeoutSettings.navigationTimeout(),
+    } = options;
+
+    const watcher = new LifecycleWatcher(this, frame, waitUntil, timeout);
+    let ensureNewDocumentNavigation = false;
+    let error = await Promise.race([
+      navigate(this._client, url, referer, frame._id),
+      watcher.timeoutOrTerminationPromise(),
+    ]);
+    if (!error) {
+      error = await Promise.race([
+        watcher.timeoutOrTerminationPromise(),
+        ensureNewDocumentNavigation ? watcher.newDocumentNavigationPromise() : watcher.sameDocumentNavigationPromise(),
+      ]);
+    }
+    watcher.dispose();
+    if (error)
+      throw error;
+    return watcher.navigationResponse();
+
+    async function navigate(client: CDPSession, url: string, referrer: string, frameId: string): Promise<Error | null> {
+      try {
+        const response = await client.send('Page.navigate', {url, referrer, frameId});
+        ensureNewDocumentNavigation = !!response.loaderId;
+        return response.errorText ? new Error(`${response.errorText} at ${url}`) : null;
+      } catch (error) {
+        return error;
+      }
+    }
+  }
+
+  async waitForFrameNavigation(
+    frame: Frame,
+    options: { timeout?: number; waitUntil?: string | string[]; } = {}
+  ): Promise<Response | null> {
+    assertNoLegacyNavigationOptions(options);
+    const {
+      waitUntil = ['load'],
+      timeout = this._timeoutSettings.navigationTimeout(),
+    } = options;
+    const watcher = new LifecycleWatcher(this, frame, waitUntil, timeout);
+    const error = await Promise.race([
+      watcher.timeoutOrTerminationPromise(),
+      watcher.sameDocumentNavigationPromise(),
+      watcher.newDocumentNavigationPromise()
+    ]);
+    watcher.dispose();
+    if (error)
+      throw error;
+    return watcher.navigationResponse();
+  }
+
+  _onLifecycleEvent(event: Protocol.Page.lifecycleEventPayload) {
+    const frame = this._frames.get(event.frameId);
+    if (!frame)
+      return;
+    frame._onLifecycleEvent(event.loaderId, event.name);
+    this.emit(FrameManagerEvents.LifecycleEvent, frame);
+  }
+
+  _onFrameStoppedLoading(frameId: string) {
+    const frame = this._frames.get(frameId);
+    if (!frame)
+      return;
+    frame._onLoadingStopped();
+    this.emit(FrameManagerEvents.LifecycleEvent, frame);
+  }
+
+  _handleFrameTree(frameTree: Protocol.Page.FrameTree) {
+    if (frameTree.frame.parentId)
+      this._onFrameAttached(frameTree.frame.id, frameTree.frame.parentId);
+    this._onFrameNavigated(frameTree.frame);
+    if (!frameTree.childFrames)
+      return;
+
+    for (const child of frameTree.childFrames)
+      this._handleFrameTree(child);
+  }
+
+  page(): Page {
+    return this._page;
+  }
+
+  mainFrame(): Frame {
+    return this._mainFrame;
+  }
+
+  frames(): Frame[] {
+    return Array.from(this._frames.values());
+  }
+
+  frame(frameId: string): Frame | null {
+    return this._frames.get(frameId) || null;
+  }
+
+  _onFrameAttached(frameId: string, parentFrameId: string | null) {
+    if (this._frames.has(frameId))
+      return;
+    assert(parentFrameId);
+    const parentFrame = this._frames.get(parentFrameId);
+    const frame = new Frame(this, this._client, parentFrame, frameId);
+    this._frames.set(frame._id, frame);
+    this.emit(FrameManagerEvents.FrameAttached, frame);
+  }
+
+  _onFrameNavigated(framePayload: Protocol.Page.Frame) {
+    const isMainFrame = !framePayload.parentId;
+    let frame = isMainFrame ? this._mainFrame : this._frames.get(framePayload.id);
+    assert(isMainFrame || frame, 'We either navigate top level or have old version of the navigated frame');
+
+    // Detach all child frames first.
+    if (frame) {
+      for (const child of frame.childFrames())
+        this._removeFramesRecursively(child);
+    }
+
+    // Update or create main frame.
+    if (isMainFrame) {
+      if (frame) {
+        // Update frame id to retain frame identity on cross-process navigation.
+        this._frames.delete(frame._id);
+        frame._id = framePayload.id;
+      } else {
+        // Initial main frame navigation.
+        frame = new Frame(this, this._client, null, framePayload.id);
+      }
+      this._frames.set(framePayload.id, frame);
+      this._mainFrame = frame;
+    }
+
+    // Update frame payload.
+    frame._navigated(framePayload);
+
+    this.emit(FrameManagerEvents.FrameNavigated, frame);
+  }
+
+  async _ensureIsolatedWorld(name: string) {
+    if (this._isolatedWorlds.has(name))
+      return;
+    this._isolatedWorlds.add(name);
+    await this._client.send('Page.addScriptToEvaluateOnNewDocument', {
+      source: `//# sourceURL=${EVALUATION_SCRIPT_URL}`,
+      worldName: name,
+    }),
+    await Promise.all(this.frames().map(frame => this._client.send('Page.createIsolatedWorld', {
+      frameId: frame._id,
+      grantUniveralAccess: true,
+      worldName: name,
+    }).catch(debugError))); // frames might be removed before we send this
+  }
+
+  _onFrameNavigatedWithinDocument(frameId: string, url: string) {
+    const frame = this._frames.get(frameId);
+    if (!frame)
+      return;
+    frame._navigatedWithinDocument(url);
+    this.emit(FrameManagerEvents.FrameNavigatedWithinDocument, frame);
+    this.emit(FrameManagerEvents.FrameNavigated, frame);
+  }
+
+  _onFrameDetached(frameId: string) {
+    const frame = this._frames.get(frameId);
+    if (frame)
+      this._removeFramesRecursively(frame);
+  }
+
+  _onExecutionContextCreated(contextPayload) {
+    const frameId = contextPayload.auxData ? contextPayload.auxData.frameId : null;
+    const frame = this._frames.get(frameId) || null;
+    let world = null;
+    if (frame) {
+      if (contextPayload.auxData && !!contextPayload.auxData['isDefault']) {
+        world = frame._mainWorld;
+      } else if (contextPayload.name === UTILITY_WORLD_NAME && !frame._secondaryWorld._hasContext()) {
+        // In case of multiple sessions to the same target, there's a race between
+        // connections so we might end up creating multiple isolated worlds.
+        // We can use either.
+        world = frame._secondaryWorld;
+      }
+    }
+    if (contextPayload.auxData && contextPayload.auxData['type'] === 'isolated')
+      this._isolatedWorlds.add(contextPayload.name);
+    const context: ExecutionContext = new ExecutionContext(this._client, contextPayload, world);
+    if (world)
+      world._setContext(context);
+    this._contextIdToContext.set(contextPayload.id, context);
+  }
+
+  _onExecutionContextDestroyed(executionContextId: number) {
+    const context = this._contextIdToContext.get(executionContextId);
+    if (!context)
+      return;
+    this._contextIdToContext.delete(executionContextId);
+    if (context._world)
+      context._world._setContext(null);
+  }
+
+  _onExecutionContextsCleared() {
+    for (const context of this._contextIdToContext.values()) {
+      if (context._world)
+        context._world._setContext(null);
+    }
+    this._contextIdToContext.clear();
+  }
+
+  executionContextById(contextId: number): ExecutionContext {
+    const context = this._contextIdToContext.get(contextId);
+    assert(context, 'INTERNAL ERROR: missing context with id = ' + contextId);
+    return context;
+  }
+
+  _removeFramesRecursively(frame: Frame) {
+    for (const child of frame.childFrames())
+      this._removeFramesRecursively(child);
+    frame._detach();
+    this._frames.delete(frame._id);
+    this.emit(FrameManagerEvents.FrameDetached, frame);
+  }
+}
+
+function assertNoLegacyNavigationOptions(options) {
+  assert(options['networkIdleTimeout'] === undefined, 'ERROR: networkIdleTimeout option is no longer supported.');
+  assert(options['networkIdleInflight'] === undefined, 'ERROR: networkIdleInflight option is no longer supported.');
+  assert(options.waitUntil !== 'networkidle', 'ERROR: "networkidle" option is no longer supported. Use "networkidle2" instead');
+}
--- a/src/chromium/Input.ts
+++ b/src/chromium/Input.ts
@ -0,0 +1,337 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSession } from './Connection';
+import { assert } from '../helper';
+import { keyDefinitions } from '../USKeyboardLayout';
+
+type KeyDescription = {
+  keyCode: number,
+  key: string,
+  text: string,
+  code: string,
+  location: number,
+};
+
+export type Modifier = 'Alt' | 'Control' | 'Meta' | 'Shift';
+const kModifiers: Modifier[] = ['Alt', 'Control', 'Meta', 'Shift'];
+
+export type Button = 'left' | 'right' | 'middle';
+
+export class Keyboard {
+  private _client: CDPSession;
+  _modifiers = 0;
+  private _pressedKeys = new Set<unknown>();
+
+  constructor(client: CDPSession) {
+    this._client = client;
+  }
+
+  async down(key: string, options: { text?: string; } = { text: undefined }) {
+    const description = this._keyDescriptionForString(key);
+
+    const autoRepeat = this._pressedKeys.has(description.code);
+    this._pressedKeys.add(description.code);
+    this._modifiers |= this._modifierBit(description.key);
+
+    const text = options.text === undefined ? description.text : options.text;
+    await this._client.send('Input.dispatchKeyEvent', {
+      type: text ? 'keyDown' : 'rawKeyDown',
+      modifiers: this._modifiers,
+      windowsVirtualKeyCode: description.keyCode,
+      code: description.code,
+      key: description.key,
+      text: text,
+      unmodifiedText: text,
+      autoRepeat,
+      location: description.location,
+      isKeypad: description.location === 3
+    });
+  }
+
+  _modifierBit(key: string): number {
+    if (key === 'Alt')
+      return 1;
+    if (key === 'Control')
+      return 2;
+    if (key === 'Meta')
+      return 4;
+    if (key === 'Shift')
+      return 8;
+    return 0;
+  }
+
+  _keyDescriptionForString(keyString: string): KeyDescription {
+    const shift = this._modifiers & 8;
+    const description = {
+      key: '',
+      keyCode: 0,
+      code: '',
+      text: '',
+      location: 0
+    };
+
+    const definition = keyDefinitions[keyString];
+    assert(definition, `Unknown key: "${keyString}"`);
+
+    if (definition.key)
+      description.key = definition.key;
+    if (shift && definition.shiftKey)
+      description.key = definition.shiftKey;
+
+    if (definition.keyCode)
+      description.keyCode = definition.keyCode;
+    if (shift && definition.shiftKeyCode)
+      description.keyCode = definition.shiftKeyCode;
+
+    if (definition.code)
+      description.code = definition.code;
+
+    if (definition.location)
+      description.location = definition.location;
+
+    if (description.key.length === 1)
+      description.text = description.key;
+
+    if (definition.text)
+      description.text = definition.text;
+    if (shift && definition.shiftText)
+      description.text = definition.shiftText;
+
+    // if any modifiers besides shift are pressed, no text should be sent
+    if (this._modifiers & ~8)
+      description.text = '';
+
+    return description;
+  }
+
+  async up(key: string) {
+    const description = this._keyDescriptionForString(key);
+
+    this._modifiers &= ~this._modifierBit(description.key);
+    this._pressedKeys.delete(description.code);
+    await this._client.send('Input.dispatchKeyEvent', {
+      type: 'keyUp',
+      modifiers: this._modifiers,
+      key: description.key,
+      windowsVirtualKeyCode: description.keyCode,
+      code: description.code,
+      location: description.location
+    });
+  }
+
+  async sendCharacter(char: string) {
+    await this._client.send('Input.insertText', {text: char});
+  }
+
+  async type(text: string, options: { delay: (number | undefined); } | undefined) {
+    const delay = (options && options.delay) || null;
+    for (const char of text) {
+      if (keyDefinitions[char]) {
+        await this.press(char, {delay});
+      } else {
+        if (delay)
+          await new Promise(f => setTimeout(f, delay));
+        await this.sendCharacter(char);
+      }
+    }
+  }
+
+  async press(key: string, options: { delay?: number; text?: string; } = {}) {
+    const {delay = null} = options;
+    await this.down(key, options);
+    if (delay)
+      await new Promise(f => setTimeout(f, options.delay));
+    await this.up(key);
+  }
+
+  async _ensureModifiers(modifiers: Modifier[]): Promise<Modifier[]> {
+    for (const modifier of modifiers) {
+      if (!kModifiers.includes(modifier))
+        throw new Error('Uknown modifier ' + modifier);
+    }
+    const restore: Modifier[] = [];
+    const promises: Promise<void>[] = [];
+    for (const key of kModifiers) {
+      const needDown = modifiers.includes(key);
+      const isDown = (this._modifiers & this._modifierBit(key)) !== 0;
+      if (isDown)
+        restore.push(key);
+      if (needDown && !isDown)
+        promises.push(this.down(key));
+      else if (!needDown && isDown)
+        promises.push(this.up(key));
+    }
+    await Promise.all(promises);
+    return restore;
+  }
+}
+
+export class Mouse {
+  private _client: CDPSession;
+  private _keyboard: Keyboard;
+  private _x = 0;
+  private _y = 0;
+  private _button: 'none' | Button = 'none';
+
+  constructor(client: CDPSession, keyboard: Keyboard) {
+    this._client = client;
+    this._keyboard = keyboard;
+  }
+
+  async move(x: number, y: number, options: { steps?: number; } = {}) {
+    const {steps = 1} = options;
+    const fromX = this._x, fromY = this._y;
+    this._x = x;
+    this._y = y;
+    for (let i = 1; i <= steps; i++) {
+      await this._client.send('Input.dispatchMouseEvent', {
+        type: 'mouseMoved',
+        button: this._button,
+        x: fromX + (this._x - fromX) * (i / steps),
+        y: fromY + (this._y - fromY) * (i / steps),
+        modifiers: this._keyboard._modifiers
+      });
+    }
+  }
+
+  async click(x: number, y: number, options: { delay?: number; button?: Button; clickCount?: number; } = {}) {
+    const {delay = null} = options;
+    if (delay !== null) {
+      await Promise.all([
+        this.move(x, y),
+        this.down(options),
+      ]);
+      await new Promise(f => setTimeout(f, delay));
+      await this.up(options);
+    } else {
+      await Promise.all([
+        this.move(x, y),
+        this.down(options),
+        this.up(options),
+      ]);
+    }
+  }
+
+  async dblclick(x: number, y: number, options: { delay?: number; button?: Button; } = {}) {
+    const { delay = null } = options;
+    if (delay !== null) {
+      await this.move(x, y);
+      await this.down({ ...options, clickCount: 1 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.up({ ...options, clickCount: 1 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.down({ ...options, clickCount: 2 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.up({ ...options, clickCount: 2 });
+    } else {
+      await Promise.all([
+        this.move(x, y),
+        this.down({ ...options, clickCount: 1 }),
+        this.up({ ...options, clickCount: 1 }),
+        this.down({ ...options, clickCount: 2 }),
+        this.up({ ...options, clickCount: 2 }),
+      ]);
+    }
+  }
+
+  async tripleclick(x: number, y: number, options: { delay?: number; button?: Button; } = {}) {
+    const { delay = null } = options;
+    if (delay !== null) {
+      await this.move(x, y);
+      await this.down({ ...options, clickCount: 1 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.up({ ...options, clickCount: 1 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.down({ ...options, clickCount: 2 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.up({ ...options, clickCount: 2 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.down({ ...options, clickCount: 3 });
+      await new Promise(f => setTimeout(f, delay));
+      await this.up({ ...options, clickCount: 3 });
+    } else {
+      await Promise.all([
+        this.move(x, y),
+        this.down({ ...options, clickCount: 1 }),
+        this.up({ ...options, clickCount: 1 }),
+        this.down({ ...options, clickCount: 2 }),
+        this.up({ ...options, clickCount: 2 }),
+        this.down({ ...options, clickCount: 3 }),
+        this.up({ ...options, clickCount: 3 }),
+      ]);
+    }
+  }
+
+  async down(options: { button?: Button; clickCount?: number; } = {}) {
+    const {button = 'left', clickCount = 1} = options;
+    this._button = button;
+    await this._client.send('Input.dispatchMouseEvent', {
+      type: 'mousePressed',
+      button,
+      x: this._x,
+      y: this._y,
+      modifiers: this._keyboard._modifiers,
+      clickCount
+    });
+  }
+
+  async up(options: { button?: Button; clickCount?: number; } = {}) {
+    const {button = 'left', clickCount = 1} = options;
+    this._button = 'none';
+    await this._client.send('Input.dispatchMouseEvent', {
+      type: 'mouseReleased',
+      button,
+      x: this._x,
+      y: this._y,
+      modifiers: this._keyboard._modifiers,
+      clickCount
+    });
+  }
+}
+
+export class Touchscreen {
+  private _client: CDPSession;
+  private _keyboard: Keyboard;
+
+  constructor(client: CDPSession, keyboard: Keyboard) {
+    this._client = client;
+    this._keyboard = keyboard;
+  }
+
+  async tap(x: number, y: number) {
+    // Touches appear to be lost during the first frame after navigation.
+    // This waits a frame before sending the tap.
+    // @see https://crbug.com/613219
+    await this._client.send('Runtime.evaluate', {
+      expression: 'new Promise(x => requestAnimationFrame(() => requestAnimationFrame(x)))',
+      awaitPromise: true
+    });
+
+    const touchPoints = [{x: Math.round(x), y: Math.round(y)}];
+    await this._client.send('Input.dispatchTouchEvent', {
+      type: 'touchStart',
+      touchPoints,
+      modifiers: this._keyboard._modifiers
+    });
+    await this._client.send('Input.dispatchTouchEvent', {
+      type: 'touchEnd',
+      touchPoints: [],
+      modifiers: this._keyboard._modifiers
+    });
+  }
+}
--- a/src/chromium/JSHandle.ts
+++ b/src/chromium/JSHandle.ts
@ -0,0 +1,578 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as path from 'path';
+import { CDPSession } from './Connection';
+import { ExecutionContext } from './ExecutionContext';
+import { Frame } from './Frame';
+import { FrameManager } from './FrameManager';
+import { assert, debugError, helper } from '../helper';
+import { valueFromRemoteObject, releaseObject } from './protocolHelper';
+import { Page } from './Page';
+import { Modifier, Button } from './Input';
+import { Protocol } from './protocol';
+
+type Point = {
+  x: number;
+  y: number;
+};
+
+export type PointerActionOptions = {
+  modifiers?: Modifier[];
+  relativePoint?: Point;
+};
+
+export type ClickOptions = PointerActionOptions & {
+  delay?: number;
+  button?: Button;
+  clickCount?: number;
+};
+
+export type MultiClickOptions = PointerActionOptions & {
+  delay?: number;
+  button?: Button;
+};
+
+export function createJSHandle(context: ExecutionContext, remoteObject: Protocol.Runtime.RemoteObject) {
+  const frame = context.frame();
+  if (remoteObject.subtype === 'node' && frame) {
+    const frameManager = frame._frameManager;
+    return new ElementHandle(context, context._client, remoteObject, frameManager.page(), frameManager);
+  }
+  return new JSHandle(context, context._client, remoteObject);
+}
+
+export class JSHandle {
+  _context: ExecutionContext;
+  protected _client: CDPSession;
+  _remoteObject: Protocol.Runtime.RemoteObject;
+  _disposed = false;
+
+  constructor(context: ExecutionContext, client: CDPSession, remoteObject: Protocol.Runtime.RemoteObject) {
+    this._context = context;
+    this._client = client;
+    this._remoteObject = remoteObject;
+  }
+
+  executionContext(): ExecutionContext {
+    return this._context;
+  }
+
+  async evaluate(pageFunction: Function | string, ...args: any[]): Promise<(any)> {
+    return await this.executionContext().evaluate(pageFunction, this, ...args);
+  }
+
+  async evaluateHandle(pageFunction: Function | string, ...args: any[]): Promise<JSHandle> {
+    return await this.executionContext().evaluateHandle(pageFunction, this, ...args);
+  }
+
+  async getProperty(propertyName: string): Promise<JSHandle | null> {
+    const objectHandle = await this.evaluateHandle((object, propertyName) => {
+      const result = {__proto__: null};
+      result[propertyName] = object[propertyName];
+      return result;
+    }, propertyName);
+    const properties = await objectHandle.getProperties();
+    const result = properties.get(propertyName) || null;
+    await objectHandle.dispose();
+    return result;
+  }
+
+  async getProperties(): Promise<Map<string, JSHandle>> {
+    const response = await this._client.send('Runtime.getProperties', {
+      objectId: this._remoteObject.objectId,
+      ownProperties: true
+    });
+    const result = new Map();
+    for (const property of response.result) {
+      if (!property.enumerable)
+        continue;
+      result.set(property.name, createJSHandle(this._context, property.value));
+    }
+    return result;
+  }
+
+  async jsonValue(): Promise<object | null> {
+    if (this._remoteObject.objectId) {
+      const response = await this._client.send('Runtime.callFunctionOn', {
+        functionDeclaration: 'function() { return this; }',
+        objectId: this._remoteObject.objectId,
+        returnByValue: true,
+        awaitPromise: true,
+      });
+      return valueFromRemoteObject(response.result);
+    }
+    return valueFromRemoteObject(this._remoteObject);
+  }
+
+  asElement(): ElementHandle | null {
+    return null;
+  }
+
+  async dispose() {
+    if (this._disposed)
+      return;
+    this._disposed = true;
+    await releaseObject(this._client, this._remoteObject);
+  }
+
+  toString(): string {
+    if (this._remoteObject.objectId) {
+      const type =  this._remoteObject.subtype || this._remoteObject.type;
+      return 'JSHandle@' + type;
+    }
+    return 'JSHandle:' + valueFromRemoteObject(this._remoteObject);
+  }
+}
+
+export class ElementHandle extends JSHandle {
+  private _page: Page;
+  private _frameManager: FrameManager;
+
+  constructor(context: ExecutionContext, client: CDPSession, remoteObject: Protocol.Runtime.RemoteObject, page: Page, frameManager: FrameManager) {
+    super(context, client, remoteObject);
+    this._client = client;
+    this._remoteObject = remoteObject;
+    this._page = page;
+    this._frameManager = frameManager;
+  }
+
+  asElement(): ElementHandle | null {
+    return this;
+  }
+
+  async contentFrame(): Promise<Frame|null> {
+    const nodeInfo = await this._client.send('DOM.describeNode', {
+      objectId: this._remoteObject.objectId
+    });
+    if (typeof nodeInfo.node.frameId !== 'string')
+      return null;
+    return this._frameManager.frame(nodeInfo.node.frameId);
+  }
+
+  async _scrollIntoViewIfNeeded() {
+    const error = await this.evaluate(async(element, pageJavascriptEnabled) => {
+      if (!element.isConnected)
+        return 'Node is detached from document';
+      if (element.nodeType !== Node.ELEMENT_NODE)
+        return 'Node is not of type HTMLElement';
+      // force-scroll if page's javascript is disabled.
+      if (!pageJavascriptEnabled) {
+        element.scrollIntoView({block: 'center', inline: 'center', behavior: 'instant'});
+        return false;
+      }
+      const visibleRatio = await new Promise(resolve => {
+        const observer = new IntersectionObserver(entries => {
+          resolve(entries[0].intersectionRatio);
+          observer.disconnect();
+        });
+        observer.observe(element);
+      });
+      if (visibleRatio !== 1.0)
+        element.scrollIntoView({block: 'center', inline: 'center', behavior: 'instant'});
+      return false;
+    }, this._page._javascriptEnabled);
+    if (error)
+      throw new Error(error);
+  }
+
+  async _clickablePoint(): Promise<Point> {
+    const [result, layoutMetrics] = await Promise.all([
+      this._client.send('DOM.getContentQuads', {
+        objectId: this._remoteObject.objectId
+      }).catch(debugError),
+      this._client.send('Page.getLayoutMetrics'),
+    ]);
+    if (!result || !result.quads.length)
+      throw new Error('Node is either not visible or not an HTMLElement');
+    // Filter out quads that have too small area to click into.
+    const {clientWidth, clientHeight} = layoutMetrics.layoutViewport;
+    const quads = result.quads.map(quad => this._fromProtocolQuad(quad)).map(quad => this._intersectQuadWithViewport(quad, clientWidth, clientHeight)).filter(quad => computeQuadArea(quad) > 1);
+    if (!quads.length)
+      throw new Error('Node is either not visible or not an HTMLElement');
+    // Return the middle point of the first quad.
+    const quad = quads[0];
+    let x = 0;
+    let y = 0;
+    for (const point of quad) {
+      x += point.x;
+      y += point.y;
+    }
+    return {
+      x: x / 4,
+      y: y / 4
+    };
+  }
+
+  async _viewportPointAndScroll(relativePoint: Point): Promise<{point: Point, scrollX: number, scrollY: number}> {
+    const model = await this._getBoxModel();
+    let point: Point;
+    if (!model) {
+      point = relativePoint;
+    } else {
+      // Use padding quad to be compatible with offsetX/offsetY properties.
+      const quad = model.model.padding;
+      const x = Math.min(quad[0], quad[2], quad[4], quad[6]);
+      const y = Math.min(quad[1], quad[3], quad[5], quad[7]);
+      point = {
+        x: x + relativePoint.x,
+        y: y + relativePoint.y,
+      };
+    }
+    const metrics = await this._client.send('Page.getLayoutMetrics');
+    // Give one extra pixel to avoid any issues on viewport edge.
+    let scrollX = 0;
+    if (point.x < 1)
+      scrollX = point.x - 1;
+    if (point.x > metrics.layoutViewport.clientWidth - 1)
+      scrollX = point.x - metrics.layoutViewport.clientWidth + 1;
+    let scrollY = 0;
+    if (point.y < 1)
+      scrollY = point.y - 1;
+    if (point.y > metrics.layoutViewport.clientHeight - 1)
+      scrollY = point.y - metrics.layoutViewport.clientHeight + 1;
+    return { point, scrollX, scrollY };
+  }
+
+  async _performPointerAction(action: (point: Point) => Promise<void>, options?: PointerActionOptions): Promise<void> {
+    await this._scrollIntoViewIfNeeded();
+    let point: Point;
+    if (options && options.relativePoint) {
+      let r = await this._viewportPointAndScroll(options.relativePoint);
+      if (r.scrollX || r.scrollY) {
+        const error = await this.evaluate((element, scrollX, scrollY) => {
+          if (!element.ownerDocument || !element.ownerDocument.defaultView)
+            return 'Node does not have a containing window';
+          element.ownerDocument.defaultView.scrollBy(scrollX, scrollY);
+          return false;
+        }, r.scrollX, r.scrollY);
+        if (error)
+          throw new Error(error);
+        r = await this._viewportPointAndScroll(options.relativePoint);
+        if (r.scrollX || r.scrollY)
+          throw new Error('Failed to scroll relative point into viewport');
+      }
+      point = r.point;
+    } else {
+      await this._scrollIntoViewIfNeeded();
+      point = await this._clickablePoint();
+    }
+    let restoreModifiers: Modifier[] | undefined;
+    if (options && options.modifiers)
+      restoreModifiers = await this._page.keyboard._ensureModifiers(options.modifiers);
+    await action(point);
+    if (restoreModifiers)
+      await this._page.keyboard._ensureModifiers(restoreModifiers);
+  }
+
+  _getBoxModel(): Promise<void | Protocol.DOM.getBoxModelReturnValue> {
+    return this._client.send('DOM.getBoxModel', {
+      objectId: this._remoteObject.objectId
+    }).catch(error => debugError(error));
+  }
+
+  _fromProtocolQuad(quad: number[]): Array<{ x: number; y: number; }> {
+    return [
+      {x: quad[0], y: quad[1]},
+      {x: quad[2], y: quad[3]},
+      {x: quad[4], y: quad[5]},
+      {x: quad[6], y: quad[7]}
+    ];
+  }
+
+  _intersectQuadWithViewport(quad: Array<{ x: number; y: number; }>, width: number, height: number): Array<{ x: number; y: number; }> {
+    return quad.map(point => ({
+      x: Math.min(Math.max(point.x, 0), width),
+      y: Math.min(Math.max(point.y, 0), height),
+    }));
+  }
+
+  hover(options?: PointerActionOptions): Promise<void> {
+    return this._performPointerAction(point => this._page.mouse.move(point.x, point.y), options);
+  }
+
+  click(options?: ClickOptions): Promise<void> {
+    return this._performPointerAction(point => this._page.mouse.click(point.x, point.y, options), options);
+  }
+
+  dblclick(options?: MultiClickOptions): Promise<void> {
+    return this._performPointerAction(point => this._page.mouse.dblclick(point.x, point.y, options), options);
+  }
+
+  tripleclick(options?: MultiClickOptions): Promise<void> {
+    return this._performPointerAction(point => this._page.mouse.tripleclick(point.x, point.y, options), options);
+  }
+
+  async select(...values: string[]): Promise<string[]> {
+    for (const value of values)
+      assert(helper.isString(value), 'Values must be strings. Found value "' + value + '" of type "' + (typeof value) + '"');
+    return this.evaluate((element: HTMLSelectElement, values: string[]) => {
+      if (element.nodeName.toLowerCase() !== 'select')
+        throw new Error('Element is not a <select> element.');
+
+      const options = Array.from(element.options);
+      element.value = undefined;
+      for (const option of options) {
+        option.selected = values.includes(option.value);
+        if (option.selected && !element.multiple)
+          break;
+      }
+      element.dispatchEvent(new Event('input', { 'bubbles': true }));
+      element.dispatchEvent(new Event('change', { 'bubbles': true }));
+      return options.filter(option => option.selected).map(option => option.value);
+    }, values);
+  }
+
+  async fill(value: string): Promise<void> {
+    assert(helper.isString(value), 'Value must be string. Found value "' + value + '" of type "' + (typeof value) + '"');
+    const error = await this.evaluate((element: HTMLElement) => {
+      if (element.nodeType !== Node.ELEMENT_NODE)
+        return 'Node is not of type HTMLElement';
+      if (element.nodeName.toLowerCase() === 'input') {
+        const input = element as HTMLInputElement;
+        const type = input.getAttribute('type') || '';
+        const kTextInputTypes = new Set(['', 'password', 'search', 'tel', 'text', 'url']);
+        if (!kTextInputTypes.has(type.toLowerCase()))
+          return 'Cannot fill input of type "' + type + '".';
+        input.selectionStart = 0;
+        input.selectionEnd = input.value.length;
+      } else if (element.nodeName.toLowerCase() === 'textarea') {
+        const textarea = element as HTMLTextAreaElement;
+        textarea.selectionStart = 0;
+        textarea.selectionEnd = textarea.value.length;
+      } else if (element.isContentEditable) {
+        if (!element.ownerDocument || !element.ownerDocument.defaultView)
+          return 'Element does not belong to a window';
+        const range = element.ownerDocument.createRange();
+        range.selectNodeContents(element);
+        const selection = element.ownerDocument.defaultView.getSelection();
+        selection.removeAllRanges();
+        selection.addRange(range);
+      } else {
+        return 'Element is not an <input>, <textarea> or [contenteditable] element.';
+      }
+      return false;
+    });
+    if (error)
+      throw new Error(error);
+    await this.focus();
+    await this._page.keyboard.sendCharacter(value);
+  }
+
+  async uploadFile(...filePaths: string[]) {
+    const files = filePaths.map(filePath => path.resolve(filePath));
+    const objectId = this._remoteObject.objectId;
+    await this._client.send('DOM.setFileInputFiles', { objectId, files });
+  }
+
+  tap(options?: PointerActionOptions): Promise<void> {
+    return this._performPointerAction(point => this._page.touchscreen.tap(point.x, point.y), options);
+  }
+
+  async focus() {
+    await this.evaluate(element => element.focus());
+  }
+
+  async type(text: string, options: { delay: (number | undefined); } | undefined) {
+    await this.focus();
+    await this._page.keyboard.type(text, options);
+  }
+
+  async press(key: string, options: { delay?: number; text?: string; } | undefined) {
+    await this.focus();
+    await this._page.keyboard.press(key, options);
+  }
+
+  async boundingBox(): Promise<{ x: number; y: number; width: number; height: number; } | null> {
+    const result = await this._getBoxModel();
+
+    if (!result)
+      return null;
+
+    const quad = result.model.border;
+    const x = Math.min(quad[0], quad[2], quad[4], quad[6]);
+    const y = Math.min(quad[1], quad[3], quad[5], quad[7]);
+    const width = Math.max(quad[0], quad[2], quad[4], quad[6]) - x;
+    const height = Math.max(quad[1], quad[3], quad[5], quad[7]) - y;
+
+    return {x, y, width, height};
+  }
+
+  async boxModel(): Promise<BoxModel | null> {
+    const result = await this._getBoxModel();
+
+    if (!result)
+      return null;
+
+    const {content, padding, border, margin, width, height} = result.model;
+    return {
+      content: this._fromProtocolQuad(content),
+      padding: this._fromProtocolQuad(padding),
+      border: this._fromProtocolQuad(border),
+      margin: this._fromProtocolQuad(margin),
+      width,
+      height
+    };
+  }
+
+  async screenshot(options: any = {}): Promise<string | Buffer> {
+    let needsViewportReset = false;
+
+    let boundingBox = await this.boundingBox();
+    assert(boundingBox, 'Node is either not visible or not an HTMLElement');
+
+    const viewport = this._page.viewport();
+
+    if (viewport && (boundingBox.width > viewport.width || boundingBox.height > viewport.height)) {
+      const newViewport = {
+        width: Math.max(viewport.width, Math.ceil(boundingBox.width)),
+        height: Math.max(viewport.height, Math.ceil(boundingBox.height)),
+      };
+      await this._page.setViewport(Object.assign({}, viewport, newViewport));
+
+      needsViewportReset = true;
+    }
+
+    await this._scrollIntoViewIfNeeded();
+
+    boundingBox = await this.boundingBox();
+    assert(boundingBox, 'Node is either not visible or not an HTMLElement');
+    assert(boundingBox.width !== 0, 'Node has 0 width.');
+    assert(boundingBox.height !== 0, 'Node has 0 height.');
+
+    const { layoutViewport: { pageX, pageY } } = await this._client.send('Page.getLayoutMetrics');
+
+    const clip = Object.assign({}, boundingBox);
+    clip.x += pageX;
+    clip.y += pageY;
+
+    const imageData = await this._page.screenshot(Object.assign({}, {
+      clip
+    }, options));
+
+    if (needsViewportReset)
+      await this._page.setViewport(viewport);
+
+    return imageData;
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    const handle = await this.evaluateHandle(
+        (element, selector) => element.querySelector(selector),
+        selector
+    );
+    const element = handle.asElement();
+    if (element)
+      return element;
+    await handle.dispose();
+    return null;
+  }
+
+  async $$(selector: string): Promise<ElementHandle[]> {
+    const arrayHandle = await this.evaluateHandle(
+        (element, selector) => element.querySelectorAll(selector),
+        selector
+    );
+    const properties = await arrayHandle.getProperties();
+    await arrayHandle.dispose();
+    const result = [];
+    for (const property of properties.values()) {
+      const elementHandle = property.asElement();
+      if (elementHandle)
+        result.push(elementHandle);
+    }
+    return result;
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: any[]): Promise<(object | undefined)> {
+    const elementHandle = await this.$(selector);
+    if (!elementHandle)
+      throw new Error(`Error: failed to find element matching selector "${selector}"`);
+    const result = await elementHandle.evaluate(pageFunction, ...args);
+    await elementHandle.dispose();
+    return result;
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: any[]): Promise<(object | undefined)> {
+    const arrayHandle = await this.evaluateHandle(
+        (element, selector) => Array.from(element.querySelectorAll(selector)),
+        selector
+    );
+
+    const result = await arrayHandle.evaluate(pageFunction, ...args);
+    await arrayHandle.dispose();
+    return result;
+  }
+
+  async $x(expression: string): Promise<ElementHandle[]> {
+    const arrayHandle = await this.evaluateHandle(
+        (element, expression) => {
+          const document = element.ownerDocument || element;
+          const iterator = document.evaluate(expression, element, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE);
+          const array = [];
+          let item;
+          while ((item = iterator.iterateNext()))
+            array.push(item);
+          return array;
+        },
+        expression
+    );
+    const properties = await arrayHandle.getProperties();
+    await arrayHandle.dispose();
+    const result = [];
+    for (const property of properties.values()) {
+      const elementHandle = property.asElement();
+      if (elementHandle)
+        result.push(elementHandle);
+    }
+    return result;
+  }
+
+  isIntersectingViewport(): Promise<boolean> {
+    return this.evaluate(async element => {
+      const visibleRatio = await new Promise(resolve => {
+        const observer = new IntersectionObserver(entries => {
+          resolve(entries[0].intersectionRatio);
+          observer.disconnect();
+        });
+        observer.observe(element);
+      });
+      return visibleRatio > 0;
+    });
+  }
+}
+
+function computeQuadArea(quad) {
+  // Compute sum of all directed areas of adjacent triangles
+  // https://en.wikipedia.org/wiki/Polygon#Simple_polygons
+  let area = 0;
+  for (let i = 0; i < quad.length; ++i) {
+    const p1 = quad[i];
+    const p2 = quad[(i + 1) % quad.length];
+    area += (p1.x * p2.y - p2.x * p1.y) / 2;
+  }
+  return Math.abs(area);
+}
+
+type BoxModel = {
+  content: {x: number, y: number}[],
+  padding: {x: number, y: number}[],
+  border: {x: number, y: number}[],
+  margin: {x: number, y: number}[],
+  width: number,
+  height : number
+};
--- a/src/chromium/Launcher.ts
+++ b/src/chromium/Launcher.ts
@ -0,0 +1,404 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import * as childProcess from 'child_process';
+import * as fs from 'fs';
+import * as http from 'http';
+import * as https from 'https';
+import * as os from 'os';
+import * as path from 'path';
+import * as readline from 'readline';
+import * as removeFolder from 'rimraf';
+import * as URL from 'url';
+import { Browser } from './Browser';
+import { BrowserFetcher } from './BrowserFetcher';
+import { Connection } from './Connection';
+import { TimeoutError } from '../Errors';
+import { assert, debugError, helper } from '../helper';
+import { Viewport } from './Page';
+import { PipeTransport } from './PipeTransport';
+import { WebSocketTransport } from './WebSocketTransport';
+import { ConnectionTransport } from '../ConnectionTransport';
+
+const mkdtempAsync = helper.promisify(fs.mkdtemp);
+const removeFolderAsync = helper.promisify(removeFolder);
+
+const CHROME_PROFILE_PATH = path.join(os.tmpdir(), 'playwright_dev_profile-');
+
+const DEFAULT_ARGS = [
+  '--disable-background-networking',
+  '--enable-features=NetworkService,NetworkServiceInProcess',
+  '--disable-background-timer-throttling',
+  '--disable-backgrounding-occluded-windows',
+  '--disable-breakpad',
+  '--disable-client-side-phishing-detection',
+  '--disable-component-extensions-with-background-pages',
+  '--disable-default-apps',
+  '--disable-dev-shm-usage',
+  '--disable-extensions',
+  // BlinkGenPropertyTrees disabled due to crbug.com/937609
+  '--disable-features=TranslateUI,BlinkGenPropertyTrees',
+  '--disable-hang-monitor',
+  '--disable-ipc-flooding-protection',
+  '--disable-popup-blocking',
+  '--disable-prompt-on-repost',
+  '--disable-renderer-backgrounding',
+  '--disable-sync',
+  '--force-color-profile=srgb',
+  '--metrics-recording-only',
+  '--no-first-run',
+  '--enable-automation',
+  '--password-store=basic',
+  '--use-mock-keychain',
+];
+
+export class Launcher {
+  private _projectRoot: string;
+  private _preferredRevision: string;
+  private _isPlaywrightCore: boolean;
+
+  constructor(projectRoot: string, preferredRevision: string, isPlaywrightCore: boolean) {
+    this._projectRoot = projectRoot;
+    this._preferredRevision = preferredRevision;
+    this._isPlaywrightCore = isPlaywrightCore;
+  }
+
+  async launch(options: (LauncherLaunchOptions & LauncherChromeArgOptions & LauncherBrowserOptions) = {}): Promise<Browser> {
+    const {
+      ignoreDefaultArgs = false,
+      args = [],
+      dumpio = false,
+      executablePath = null,
+      pipe = false,
+      env = process.env,
+      handleSIGINT = true,
+      handleSIGTERM = true,
+      handleSIGHUP = true,
+      ignoreHTTPSErrors = false,
+      defaultViewport = {width: 800, height: 600},
+      slowMo = 0,
+      timeout = 30000
+    } = options;
+
+    const chromeArguments = [];
+    if (!ignoreDefaultArgs)
+      chromeArguments.push(...this.defaultArgs(options));
+    else if (Array.isArray(ignoreDefaultArgs))
+      chromeArguments.push(...this.defaultArgs(options).filter(arg => ignoreDefaultArgs.indexOf(arg) === -1));
+    else
+      chromeArguments.push(...args);
+
+    let temporaryUserDataDir = null;
+
+    if (!chromeArguments.some(argument => argument.startsWith('--remote-debugging-')))
+      chromeArguments.push(pipe ? '--remote-debugging-pipe' : '--remote-debugging-port=0');
+    if (!chromeArguments.some(arg => arg.startsWith('--user-data-dir'))) {
+      temporaryUserDataDir = await mkdtempAsync(CHROME_PROFILE_PATH);
+      chromeArguments.push(`--user-data-dir=${temporaryUserDataDir}`);
+    }
+
+    let chromeExecutable = executablePath;
+    if (!executablePath) {
+      const {missingText, executablePath} = this._resolveExecutablePath();
+      if (missingText)
+        throw new Error(missingText);
+      chromeExecutable = executablePath;
+    }
+
+    const usePipe = chromeArguments.includes('--remote-debugging-pipe');
+    let stdio: ('ignore' | 'pipe')[] = ['pipe', 'pipe', 'pipe'];
+    if (usePipe) {
+      if (dumpio)
+        stdio = ['ignore', 'pipe', 'pipe', 'pipe', 'pipe'];
+      else
+        stdio = ['ignore', 'ignore', 'ignore', 'pipe', 'pipe'];
+    }
+    const chromeProcess = childProcess.spawn(
+        chromeExecutable,
+        chromeArguments,
+        {
+          // On non-windows platforms, `detached: true` makes child process a leader of a new
+          // process group, making it possible to kill child process tree with `.kill(-pid)` command.
+          // @see https://nodejs.org/api/child_process.html#child_process_options_detached
+          detached: process.platform !== 'win32',
+          env,
+          stdio
+        }
+    );
+
+    if (dumpio) {
+      chromeProcess.stderr.pipe(process.stderr);
+      chromeProcess.stdout.pipe(process.stdout);
+    }
+
+    let chromeClosed = false;
+    const waitForChromeToClose = new Promise((fulfill, reject) => {
+      chromeProcess.once('exit', () => {
+        chromeClosed = true;
+        // Cleanup as processes exit.
+        if (temporaryUserDataDir) {
+          removeFolderAsync(temporaryUserDataDir)
+              .then(() => fulfill())
+              .catch(err => console.error(err));
+        } else {
+          fulfill();
+        }
+      });
+    });
+
+    const listeners = [ helper.addEventListener(process, 'exit', killChrome) ];
+    if (handleSIGINT)
+      listeners.push(helper.addEventListener(process, 'SIGINT', () => { killChrome(); process.exit(130); }));
+    if (handleSIGTERM)
+      listeners.push(helper.addEventListener(process, 'SIGTERM', gracefullyCloseChrome));
+    if (handleSIGHUP)
+      listeners.push(helper.addEventListener(process, 'SIGHUP', gracefullyCloseChrome));
+    let connection: Connection | null = null;
+    try {
+      if (!usePipe) {
+        const browserWSEndpoint = await waitForWSEndpoint(chromeProcess, timeout, this._preferredRevision);
+        const transport = await WebSocketTransport.create(browserWSEndpoint);
+        connection = new Connection(browserWSEndpoint, transport, slowMo);
+      } else {
+        const transport = new PipeTransport(chromeProcess.stdio[3] as NodeJS.WritableStream, chromeProcess.stdio[4] as NodeJS.ReadableStream);
+        connection = new Connection('', transport, slowMo);
+      }
+      const browser = await Browser.create(connection, [], ignoreHTTPSErrors, defaultViewport, chromeProcess, gracefullyCloseChrome);
+      await browser.waitForTarget(t => t.type() === 'page');
+      return browser;
+    } catch (e) {
+      killChrome();
+      throw e;
+    }
+
+    function gracefullyCloseChrome(): Promise<any> {
+      helper.removeEventListeners(listeners);
+      if (temporaryUserDataDir) {
+        killChrome();
+      } else if (connection) {
+        // Attempt to close chrome gracefully
+        connection.send('Browser.close').catch(error => {
+          debugError(error);
+          killChrome();
+        });
+      }
+      return waitForChromeToClose;
+    }
+
+    // This method has to be sync to be used as 'exit' event handler.
+    function killChrome() {
+      helper.removeEventListeners(listeners);
+      if (chromeProcess.pid && !chromeProcess.killed && !chromeClosed) {
+        // Force kill chrome.
+        try {
+          if (process.platform === 'win32')
+            childProcess.execSync(`taskkill /pid ${chromeProcess.pid} /T /F`);
+          else
+            process.kill(-chromeProcess.pid, 'SIGKILL');
+        } catch (e) {
+          // the process might have already stopped
+        }
+      }
+      // Attempt to remove temporary profile directory to avoid littering.
+      try {
+        removeFolder.sync(temporaryUserDataDir);
+      } catch (e) { }
+    }
+  }
+
+  defaultArgs(options: LauncherChromeArgOptions = {}): string[] {
+    const {
+      devtools = false,
+      headless = !devtools,
+      args = [],
+      userDataDir = null
+    } = options;
+    const chromeArguments = [...DEFAULT_ARGS];
+    if (userDataDir)
+      chromeArguments.push(`--user-data-dir=${userDataDir}`);
+    if (devtools)
+      chromeArguments.push('--auto-open-devtools-for-tabs');
+    if (headless) {
+      chromeArguments.push(
+          '--headless',
+          '--hide-scrollbars',
+          '--mute-audio'
+      );
+    }
+    if (args.every(arg => arg.startsWith('-')))
+      chromeArguments.push('about:blank');
+    chromeArguments.push(...args);
+    return chromeArguments;
+  }
+
+  executablePath(): string {
+    return this._resolveExecutablePath().executablePath;
+  }
+
+  async connect(options: (LauncherBrowserOptions & {
+      browserWSEndpoint?: string;
+      browserURL?: string;
+      transport?: ConnectionTransport; })): Promise<Browser> {
+    const {
+      browserWSEndpoint,
+      browserURL,
+      ignoreHTTPSErrors = false,
+      defaultViewport = {width: 800, height: 600},
+      transport,
+      slowMo = 0,
+    } = options;
+
+    assert(Number(!!browserWSEndpoint) + Number(!!browserURL) + Number(!!transport) === 1, 'Exactly one of browserWSEndpoint, browserURL or transport must be passed to playwright.connect');
+
+    let connection = null;
+    if (transport) {
+      connection = new Connection('', transport, slowMo);
+    } else if (browserWSEndpoint) {
+      const connectionTransport = await WebSocketTransport.create(browserWSEndpoint);
+      connection = new Connection(browserWSEndpoint, connectionTransport, slowMo);
+    } else if (browserURL) {
+      const connectionURL = await getWSEndpoint(browserURL);
+      const connectionTransport = await WebSocketTransport.create(connectionURL);
+      connection = new Connection(connectionURL, connectionTransport, slowMo);
+    }
+
+    const {browserContextIds} = await connection.send('Target.getBrowserContexts');
+    return Browser.create(connection, browserContextIds, ignoreHTTPSErrors, defaultViewport, null, () => connection.send('Browser.close').catch(debugError));
+  }
+
+  _resolveExecutablePath(): { executablePath: string; missingText: string | null; } {
+    // playwright-core doesn't take into account PLAYWRIGHT_* env variables.
+    if (!this._isPlaywrightCore) {
+      const executablePath = process.env.PLAYWRIGHT_EXECUTABLE_PATH || process.env.npm_config_playwright_executable_path || process.env.npm_package_config_playwright_executable_path;
+      if (executablePath) {
+        const missingText = !fs.existsSync(executablePath) ? 'Tried to use PLAYWRIGHT_EXECUTABLE_PATH env variable to launch browser but did not find any executable at: ' + executablePath : null;
+        return { executablePath, missingText };
+      }
+    }
+    const browserFetcher = new BrowserFetcher(this._projectRoot);
+    if (!this._isPlaywrightCore) {
+      const revision = process.env['PLAYWRIGHT_CHROMIUM_REVISION'];
+      if (revision) {
+        const revisionInfo = browserFetcher.revisionInfo(revision);
+        const missingText = !revisionInfo.local ? 'Tried to use PLAYWRIGHT_CHROMIUM_REVISION env variable to launch browser but did not find executable at: ' + revisionInfo.executablePath : null;
+        return {executablePath: revisionInfo.executablePath, missingText};
+      }
+    }
+    const revisionInfo = browserFetcher.revisionInfo(this._preferredRevision);
+    const missingText = !revisionInfo.local ? `Chromium revision is not downloaded. Run "npm install" or "yarn install"` : null;
+    return {executablePath: revisionInfo.executablePath, missingText};
+  }
+
+}
+
+function waitForWSEndpoint(chromeProcess: childProcess.ChildProcess, timeout: number, preferredRevision: string): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const rl = readline.createInterface({ input: chromeProcess.stderr });
+    let stderr = '';
+    const listeners = [
+      helper.addEventListener(rl, 'line', onLine),
+      helper.addEventListener(rl, 'close', () => onClose()),
+      helper.addEventListener(chromeProcess, 'exit', () => onClose()),
+      helper.addEventListener(chromeProcess, 'error', error => onClose(error))
+    ];
+    const timeoutId = timeout ? setTimeout(onTimeout, timeout) : 0;
+
+    function onClose(error?: Error) {
+      cleanup();
+      reject(new Error([
+        'Failed to launch chrome!' + (error ? ' ' + error.message : ''),
+        stderr,
+        '',
+        'TROUBLESHOOTING: https://github.com/Microsoft/playwright/blob/master/docs/troubleshooting.md',
+        '',
+      ].join('\n')));
+    }
+
+    function onTimeout() {
+      cleanup();
+      reject(new TimeoutError(`Timed out after ${timeout} ms while trying to connect to Chrome! The only Chrome revision guaranteed to work is r${preferredRevision}`));
+    }
+
+    function onLine(line: string) {
+      stderr += line + '\n';
+      const match = line.match(/^DevTools listening on (ws:\/\/.*)$/);
+      if (!match)
+        return;
+      cleanup();
+      resolve(match[1]);
+    }
+
+    function cleanup() {
+      if (timeoutId)
+        clearTimeout(timeoutId);
+      helper.removeEventListeners(listeners);
+    }
+  });
+}
+
+function getWSEndpoint(browserURL: string): Promise<string> {
+  let resolve, reject;
+  const promise = new Promise<string>((res, rej) => { resolve = res; reject = rej; });
+
+  const endpointURL = URL.resolve(browserURL, '/json/version');
+  const protocol = endpointURL.startsWith('https') ? https : http;
+  const requestOptions = Object.assign(URL.parse(endpointURL), { method: 'GET' });
+  const request = protocol.request(requestOptions, res => {
+    let data = '';
+    if (res.statusCode !== 200) {
+      // Consume response data to free up memory.
+      res.resume();
+      reject(new Error('HTTP ' + res.statusCode));
+      return;
+    }
+    res.setEncoding('utf8');
+    res.on('data', chunk => data += chunk);
+    res.on('end', () => resolve(JSON.parse(data).webSocketDebuggerUrl));
+  });
+
+  request.on('error', reject);
+  request.end();
+
+  return promise.catch(e => {
+    e.message = `Failed to fetch browser webSocket url from ${endpointURL}: ` + e.message;
+    throw e;
+  });
+}
+
+export type LauncherChromeArgOptions = {
+   headless?: boolean,
+   args?: string[],
+   userDataDir?: string,
+   devtools?: boolean,
+};
+
+export type LauncherLaunchOptions = {
+   executablePath?: string,
+   ignoreDefaultArgs?: boolean|string[],
+   handleSIGINT?: boolean,
+   handleSIGTERM?: boolean,
+   handleSIGHUP?: boolean,
+   timeout?: number,
+   dumpio?: boolean,
+   env?: {[key: string]: string} | undefined,
+   pipe?: boolean,
+};
+
+export type LauncherBrowserOptions = {
+   ignoreHTTPSErrors?: boolean,
+   defaultViewport?: Viewport | null,
+   slowMo?: number,
+};
--- a/src/chromium/LifecycleWatcher.ts
+++ b/src/chromium/LifecycleWatcher.ts
@ -0,0 +1,176 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { CDPSessionEvents } from './Connection';
+import { TimeoutError } from '../Errors';
+import { Frame } from './Frame';
+import { FrameManager, FrameManagerEvents } from './FrameManager';
+import { assert, helper, RegisteredListener } from '../helper';
+import { NetworkManagerEvents, Request, Response } from './NetworkManager';
+
+export class LifecycleWatcher {
+  private _expectedLifecycle: string[];
+  private _frameManager: FrameManager;
+  private _frame: Frame;
+  private _initialLoaderId: string;
+  private _timeout: number;
+  private _navigationRequest: Request | null = null;
+  private _eventListeners: RegisteredListener[];
+  private _sameDocumentNavigationPromise: Promise<Error | null>;
+  private _sameDocumentNavigationCompleteCallback: () => void;
+  private _lifecyclePromise: Promise<void>;
+  private _lifecycleCallback: () => void;
+  private _newDocumentNavigationPromise: Promise<Error | null>;
+  private _newDocumentNavigationCompleteCallback: () => void;
+  private _timeoutPromise: Promise<Error>;
+  private _terminationPromise: Promise<Error | null>;
+  private _terminationCallback: () => void;
+  private _maximumTimer: NodeJS.Timer;
+  private _hasSameDocumentNavigation: boolean;
+
+  constructor(frameManager: FrameManager, frame: Frame, waitUntil: string | string[], timeout: number) {
+    if (Array.isArray(waitUntil))
+      waitUntil = waitUntil.slice();
+    else if (typeof waitUntil === 'string')
+      waitUntil = [waitUntil];
+    this._expectedLifecycle = waitUntil.map(value => {
+      const protocolEvent = playwrightToProtocolLifecycle.get(value);
+      assert(protocolEvent, 'Unknown value for options.waitUntil: ' + value);
+      return protocolEvent;
+    });
+
+    this._frameManager = frameManager;
+    this._frame = frame;
+    this._initialLoaderId = frame._loaderId;
+    this._timeout = timeout;
+    this._eventListeners = [
+      helper.addEventListener(frameManager._client, CDPSessionEvents.Disconnected, () => this._terminate(new Error('Navigation failed because browser has disconnected!'))),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.LifecycleEvent, this._checkLifecycleComplete.bind(this)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.FrameNavigatedWithinDocument, this._navigatedWithinDocument.bind(this)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.FrameDetached, this._onFrameDetached.bind(this)),
+      helper.addEventListener(this._frameManager.networkManager(), NetworkManagerEvents.Request, this._onRequest.bind(this)),
+    ];
+
+    this._sameDocumentNavigationPromise = new Promise(fulfill => {
+      this._sameDocumentNavigationCompleteCallback = fulfill;
+    });
+
+    this._lifecyclePromise = new Promise(fulfill => {
+      this._lifecycleCallback = fulfill;
+    });
+
+    this._newDocumentNavigationPromise = new Promise(fulfill => {
+      this._newDocumentNavigationCompleteCallback = fulfill;
+    });
+
+    this._timeoutPromise = this._createTimeoutPromise();
+    this._terminationPromise = new Promise(fulfill => {
+      this._terminationCallback = fulfill;
+    });
+    this._checkLifecycleComplete();
+  }
+
+  _onRequest(request: Request) {
+    if (request.frame() !== this._frame || !request.isNavigationRequest())
+      return;
+    this._navigationRequest = request;
+  }
+
+  _onFrameDetached(frame: Frame) {
+    if (this._frame === frame) {
+      this._terminationCallback.call(null, new Error('Navigating frame was detached'));
+      return;
+    }
+    this._checkLifecycleComplete();
+  }
+
+  navigationResponse(): Response | null {
+    return this._navigationRequest ? this._navigationRequest.response() : null;
+  }
+
+  _terminate(error: Error) {
+    this._terminationCallback.call(null, error);
+  }
+
+  sameDocumentNavigationPromise(): Promise<Error | null> {
+    return this._sameDocumentNavigationPromise;
+  }
+
+  newDocumentNavigationPromise(): Promise<Error | null> {
+    return this._newDocumentNavigationPromise;
+  }
+
+  lifecyclePromise(): Promise<any> {
+    return this._lifecyclePromise;
+  }
+
+  timeoutOrTerminationPromise(): Promise<Error | null> {
+    return Promise.race([this._timeoutPromise, this._terminationPromise]);
+  }
+
+  _createTimeoutPromise(): Promise<Error | null> {
+    if (!this._timeout)
+      return new Promise(() => {});
+    const errorMessage = 'Navigation timeout of ' + this._timeout + ' ms exceeded';
+    return new Promise(fulfill => this._maximumTimer = setTimeout(fulfill, this._timeout))
+        .then(() => new TimeoutError(errorMessage));
+  }
+
+  _navigatedWithinDocument(frame: Frame) {
+    if (frame !== this._frame)
+      return;
+    this._hasSameDocumentNavigation = true;
+    this._checkLifecycleComplete();
+  }
+
+  _checkLifecycleComplete() {
+    // We expect navigation to commit.
+    if (!checkLifecycle(this._frame, this._expectedLifecycle))
+      return;
+    this._lifecycleCallback();
+    if (this._frame._loaderId === this._initialLoaderId && !this._hasSameDocumentNavigation)
+      return;
+    if (this._hasSameDocumentNavigation)
+      this._sameDocumentNavigationCompleteCallback();
+    if (this._frame._loaderId !== this._initialLoaderId)
+      this._newDocumentNavigationCompleteCallback();
+
+    function checkLifecycle(frame: Frame, expectedLifecycle: string[]): boolean {
+      for (const event of expectedLifecycle) {
+        if (!frame._lifecycleEvents.has(event))
+          return false;
+      }
+      for (const child of frame.childFrames()) {
+        if (!checkLifecycle(child, expectedLifecycle))
+          return false;
+      }
+      return true;
+    }
+  }
+
+  dispose() {
+    helper.removeEventListeners(this._eventListeners);
+    clearTimeout(this._maximumTimer);
+  }
+}
+
+const playwrightToProtocolLifecycle = new Map([
+  ['load', 'load'],
+  ['domcontentloaded', 'DOMContentLoaded'],
+  ['networkidle0', 'networkIdle'],
+  ['networkidle2', 'networkAlmostIdle'],
+]);
--- a/src/chromium/Multimap.ts
+++ b/src/chromium/Multimap.ts
@ -0,0 +1,93 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class Multimap<T, V> {
+  private _map: Map<T, Set<V>>;
+
+  constructor() {
+    this._map = new Map();
+  }
+
+  set(key: T, value: V) {
+    let set = this._map.get(key);
+    if (!set) {
+      set = new Set();
+      this._map.set(key, set);
+    }
+    set.add(value);
+  }
+
+  get(key: T): Set<V> {
+    let result = this._map.get(key);
+    if (!result)
+      result = new Set();
+    return result;
+  }
+
+  has(key: T): boolean {
+    return this._map.has(key);
+  }
+
+  hasValue(key: T, value: V): boolean {
+    const set = this._map.get(key);
+    if (!set)
+      return false;
+    return set.has(value);
+  }
+
+  get size(): number {
+    return this._map.size;
+  }
+
+  delete(key: T, value: V): boolean {
+    const values = this.get(key);
+    const result = values.delete(value);
+    if (!values.size)
+      this._map.delete(key);
+    return result;
+  }
+
+  deleteAll(key: T) {
+    this._map.delete(key);
+  }
+
+  firstValue(key: T): V {
+    const set = this._map.get(key);
+    if (!set)
+      return null;
+    return set.values().next().value;
+  }
+
+  firstKey(): T {
+    return this._map.keys().next().value;
+  }
+
+  valuesArray(): V[] {
+    const result = [];
+    for (const key of this._map.keys())
+      result.push(...Array.from(this._map.get(key).values()));
+    return result;
+  }
+
+  keysArray(): T[] {
+    return Array.from(this._map.keys());
+  }
+
+  clear() {
+    this._map.clear();
+  }
+}
--- a/src/chromium/NetworkManager.ts
+++ b/src/chromium/NetworkManager.ts
@ -0,0 +1,657 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { EventEmitter } from 'events';
+import { CDPSession } from './Connection';
+import { Frame } from './Frame';
+import { FrameManager } from './FrameManager';
+import { assert, debugError, helper } from '../helper';
+import { Protocol } from './protocol';
+
+export const NetworkManagerEvents = {
+  Request: Symbol('Events.NetworkManager.Request'),
+  Response: Symbol('Events.NetworkManager.Response'),
+  RequestFailed: Symbol('Events.NetworkManager.RequestFailed'),
+  RequestFinished: Symbol('Events.NetworkManager.RequestFinished'),
+};
+
+export class NetworkManager extends EventEmitter {
+  private _client: CDPSession;
+  private _ignoreHTTPSErrors: boolean;
+  private _frameManager: FrameManager;
+  private _requestIdToRequest = new Map<string, Request>();
+  private _requestIdToRequestWillBeSentEvent = new Map<string, Protocol.Network.requestWillBeSentPayload>();
+  private _extraHTTPHeaders: {[key: string]: string} = {};
+  private _offline = false;
+  private _credentials: {username: string, password: string} | null = null;
+  private _attemptedAuthentications = new Set<string>();
+  private _userRequestInterceptionEnabled = false;
+  private _protocolRequestInterceptionEnabled = false;
+  private _userCacheDisabled = false;
+  private _requestIdToInterceptionId = new Map<string, string>();
+
+  constructor(client: CDPSession, ignoreHTTPSErrors: boolean, frameManager: FrameManager) {
+    super();
+    this._client = client;
+    this._ignoreHTTPSErrors = ignoreHTTPSErrors;
+    this._frameManager = frameManager;
+
+    this._client.on('Fetch.requestPaused', this._onRequestPaused.bind(this));
+    this._client.on('Fetch.authRequired', this._onAuthRequired.bind(this));
+    this._client.on('Network.requestWillBeSent', this._onRequestWillBeSent.bind(this));
+    this._client.on('Network.requestServedFromCache', this._onRequestServedFromCache.bind(this));
+    this._client.on('Network.responseReceived', this._onResponseReceived.bind(this));
+    this._client.on('Network.loadingFinished', this._onLoadingFinished.bind(this));
+    this._client.on('Network.loadingFailed', this._onLoadingFailed.bind(this));
+  }
+
+  async initialize() {
+    await this._client.send('Network.enable');
+    if (this._ignoreHTTPSErrors)
+      await this._client.send('Security.setIgnoreCertificateErrors', {ignore: true});
+  }
+
+  async authenticate(credentials: { username: string; password: string; } | null) {
+    this._credentials = credentials;
+    await this._updateProtocolRequestInterception();
+  }
+
+  async setExtraHTTPHeaders(extraHTTPHeaders: { [s: string]: string; }) {
+    this._extraHTTPHeaders = {};
+    for (const key of Object.keys(extraHTTPHeaders)) {
+      const value = extraHTTPHeaders[key];
+      assert(helper.isString(value), `Expected value of header "${key}" to be String, but "${typeof value}" is found.`);
+      this._extraHTTPHeaders[key.toLowerCase()] = value;
+    }
+    await this._client.send('Network.setExtraHTTPHeaders', { headers: this._extraHTTPHeaders });
+  }
+
+  extraHTTPHeaders(): { [s: string]: string; } {
+    return Object.assign({}, this._extraHTTPHeaders);
+  }
+
+  async setOfflineMode(value: boolean) {
+    if (this._offline === value)
+      return;
+    this._offline = value;
+    await this._client.send('Network.emulateNetworkConditions', {
+      offline: this._offline,
+      // values of 0 remove any active throttling. crbug.com/456324#c9
+      latency: 0,
+      downloadThroughput: -1,
+      uploadThroughput: -1
+    });
+  }
+
+  async setUserAgent(userAgent: string) {
+    await this._client.send('Network.setUserAgentOverride', { userAgent });
+  }
+
+  async setCacheEnabled(enabled: boolean) {
+    this._userCacheDisabled = !enabled;
+    await this._updateProtocolCacheDisabled();
+  }
+
+  async setRequestInterception(value: boolean) {
+    this._userRequestInterceptionEnabled = value;
+    await this._updateProtocolRequestInterception();
+  }
+
+  async _updateProtocolRequestInterception() {
+    const enabled = this._userRequestInterceptionEnabled || !!this._credentials;
+    if (enabled === this._protocolRequestInterceptionEnabled)
+      return;
+    this._protocolRequestInterceptionEnabled = enabled;
+    if (enabled) {
+      await Promise.all([
+        this._updateProtocolCacheDisabled(),
+        this._client.send('Fetch.enable', {
+          handleAuthRequests: true,
+          patterns: [{urlPattern: '*'}],
+        }),
+      ]);
+    } else {
+      await Promise.all([
+        this._updateProtocolCacheDisabled(),
+        this._client.send('Fetch.disable')
+      ]);
+    }
+  }
+
+  async _updateProtocolCacheDisabled() {
+    await this._client.send('Network.setCacheDisabled', {
+      cacheDisabled: this._userCacheDisabled || this._protocolRequestInterceptionEnabled
+    });
+  }
+
+  _onRequestWillBeSent(event: Protocol.Network.requestWillBeSentPayload) {
+    // Request interception doesn't happen for data URLs with Network Service.
+    if (this._protocolRequestInterceptionEnabled && !event.request.url.startsWith('data:')) {
+      const requestId = event.requestId;
+      const interceptionId = this._requestIdToInterceptionId.get(requestId);
+      if (interceptionId) {
+        this._onRequest(event, interceptionId);
+        this._requestIdToInterceptionId.delete(requestId);
+      } else {
+        this._requestIdToRequestWillBeSentEvent.set(event.requestId, event);
+      }
+      return;
+    }
+    this._onRequest(event, null);
+  }
+
+  _onAuthRequired(event: Protocol.Fetch.authRequiredPayload) {
+    let response: 'Default' | 'CancelAuth' | 'ProvideCredentials' = 'Default';
+    if (this._attemptedAuthentications.has(event.requestId)) {
+      response = 'CancelAuth';
+    } else if (this._credentials) {
+      response = 'ProvideCredentials';
+      this._attemptedAuthentications.add(event.requestId);
+    }
+    const {username, password} = this._credentials || {username: undefined, password: undefined};
+    this._client.send('Fetch.continueWithAuth', {
+      requestId: event.requestId,
+      authChallengeResponse: { response, username, password },
+    }).catch(debugError);
+  }
+
+  _onRequestPaused(event: Protocol.Fetch.requestPausedPayload) {
+    if (!this._userRequestInterceptionEnabled && this._protocolRequestInterceptionEnabled) {
+      this._client.send('Fetch.continueRequest', {
+        requestId: event.requestId
+      }).catch(debugError);
+    }
+
+    const requestId = event.networkId;
+    const interceptionId = event.requestId;
+    if (requestId && this._requestIdToRequestWillBeSentEvent.has(requestId)) {
+      const requestWillBeSentEvent = this._requestIdToRequestWillBeSentEvent.get(requestId);
+      this._onRequest(requestWillBeSentEvent, interceptionId);
+      this._requestIdToRequestWillBeSentEvent.delete(requestId);
+    } else {
+      this._requestIdToInterceptionId.set(requestId, interceptionId);
+    }
+  }
+
+  _onRequest(event: Protocol.Network.requestWillBeSentPayload, interceptionId: string | null) {
+    let redirectChain = [];
+    if (event.redirectResponse) {
+      const request = this._requestIdToRequest.get(event.requestId);
+      // If we connect late to the target, we could have missed the requestWillBeSent event.
+      if (request) {
+        this._handleRequestRedirect(request, event.redirectResponse);
+        redirectChain = request._redirectChain;
+      }
+    }
+    const frame = event.frameId ? this._frameManager.frame(event.frameId) : null;
+    const request = new Request(this._client, frame, interceptionId, this._userRequestInterceptionEnabled, event, redirectChain);
+    this._requestIdToRequest.set(event.requestId, request);
+    this.emit(NetworkManagerEvents.Request, request);
+  }
+
+
+  _onRequestServedFromCache(event: Protocol.Network.requestServedFromCachePayload) {
+    const request = this._requestIdToRequest.get(event.requestId);
+    if (request)
+      request._fromMemoryCache = true;
+  }
+
+  _handleRequestRedirect(request: Request, responsePayload: Protocol.Network.Response) {
+    const response = new Response(this._client, request, responsePayload);
+    request._response = response;
+    request._redirectChain.push(request);
+    response._bodyLoadedPromiseFulfill.call(null, new Error('Response body is unavailable for redirect responses'));
+    this._requestIdToRequest.delete(request._requestId);
+    this._attemptedAuthentications.delete(request._interceptionId);
+    this.emit(NetworkManagerEvents.Response, response);
+    this.emit(NetworkManagerEvents.RequestFinished, request);
+  }
+
+  _onResponseReceived(event: Protocol.Network.responseReceivedPayload) {
+    const request = this._requestIdToRequest.get(event.requestId);
+    // FileUpload sends a response without a matching request.
+    if (!request)
+      return;
+    const response = new Response(this._client, request, event.response);
+    request._response = response;
+    this.emit(NetworkManagerEvents.Response, response);
+  }
+
+  _onLoadingFinished(event: Protocol.Network.loadingFinishedPayload) {
+    const request = this._requestIdToRequest.get(event.requestId);
+    // For certain requestIds we never receive requestWillBeSent event.
+    // @see https://crbug.com/750469
+    if (!request)
+      return;
+
+    // Under certain conditions we never get the Network.responseReceived
+    // event from protocol. @see https://crbug.com/883475
+    if (request.response())
+      request.response()._bodyLoadedPromiseFulfill.call(null);
+    this._requestIdToRequest.delete(request._requestId);
+    this._attemptedAuthentications.delete(request._interceptionId);
+    this.emit(NetworkManagerEvents.RequestFinished, request);
+  }
+
+  _onLoadingFailed(event: Protocol.Network.loadingFailedPayload) {
+    const request = this._requestIdToRequest.get(event.requestId);
+    // For certain requestIds we never receive requestWillBeSent event.
+    // @see https://crbug.com/750469
+    if (!request)
+      return;
+    request._failureText = event.errorText;
+    const response = request.response();
+    if (response)
+      response._bodyLoadedPromiseFulfill.call(null);
+    this._requestIdToRequest.delete(request._requestId);
+    this._attemptedAuthentications.delete(request._interceptionId);
+    this.emit(NetworkManagerEvents.RequestFailed, request);
+  }
+}
+
+export class Request {
+  _response: Response | null = null;
+  _redirectChain: Request[];
+  _requestId: string;
+  _interceptionId: string;
+  private _client: CDPSession;
+  private _isNavigationRequest: boolean;
+  private _allowInterception: boolean;
+  private _interceptionHandled = false;
+  _failureText: string | null = null;
+  private _url: string;
+  private _resourceType: string;
+  private _method: string;
+  private _postData: string;
+  private _headers: {[key: string]: string} = {};
+  private _frame: Frame;
+  _fromMemoryCache = false;
+
+  constructor(client: CDPSession, frame: Frame | null, interceptionId: string, allowInterception: boolean, event: Protocol.Network.requestWillBeSentPayload, redirectChain: Request[]) {
+    this._client = client;
+    this._requestId = event.requestId;
+    this._isNavigationRequest = event.requestId === event.loaderId && event.type === 'Document';
+    this._interceptionId = interceptionId;
+    this._allowInterception = allowInterception;
+
+    this._url = event.request.url;
+    this._resourceType = event.type.toLowerCase();
+    this._method = event.request.method;
+    this._postData = event.request.postData;
+    this._frame = frame;
+    this._redirectChain = redirectChain;
+    for (const key of Object.keys(event.request.headers))
+      this._headers[key.toLowerCase()] = event.request.headers[key];
+  }
+
+  url(): string {
+    return this._url;
+  }
+
+  resourceType(): string {
+    return this._resourceType;
+  }
+
+  method(): string {
+    return this._method;
+  }
+
+  postData(): string | undefined {
+    return this._postData;
+  }
+
+  headers(): {[key: string]: string} {
+    return this._headers;
+  }
+
+  response(): Response | null {
+    return this._response;
+  }
+
+  frame(): Frame | null {
+    return this._frame;
+  }
+
+  isNavigationRequest(): boolean {
+    return this._isNavigationRequest;
+  }
+
+  redirectChain(): Request[] {
+    return this._redirectChain.slice();
+  }
+
+  failure(): { errorText: string; } | null {
+    if (!this._failureText)
+      return null;
+    return {
+      errorText: this._failureText
+    };
+  }
+
+  async continue(overrides: { url?: string; method?: string; postData?: string; headers?: {[key: string]: string}; } = {}) {
+    // Request interception is not supported for data: urls.
+    if (this._url.startsWith('data:'))
+      return;
+    assert(this._allowInterception, 'Request Interception is not enabled!');
+    assert(!this._interceptionHandled, 'Request is already handled!');
+    const {
+      url,
+      method,
+      postData,
+      headers
+    } = overrides;
+    this._interceptionHandled = true;
+    await this._client.send('Fetch.continueRequest', {
+      requestId: this._interceptionId,
+      url,
+      method,
+      postData,
+      headers: headers ? headersArray(headers) : undefined,
+    }).catch(error => {
+      // In certain cases, protocol will return error if the request was already canceled
+      // or the page was closed. We should tolerate these errors.
+      debugError(error);
+    });
+  }
+
+  async respond(response: { status: number; headers: {[key: string]: string}; contentType: string; body: (string | Buffer); }) {
+    // Mocking responses for dataURL requests is not currently supported.
+    if (this._url.startsWith('data:'))
+      return;
+    assert(this._allowInterception, 'Request Interception is not enabled!');
+    assert(!this._interceptionHandled, 'Request is already handled!');
+    this._interceptionHandled = true;
+
+    const responseBody = response.body && helper.isString(response.body) ? Buffer.from(/** @type {string} */(response.body)) : /** @type {?Buffer} */(response.body || null);
+
+    const responseHeaders: { [s: string]: string; } = {};
+    if (response.headers) {
+      for (const header of Object.keys(response.headers))
+        responseHeaders[header.toLowerCase()] = response.headers[header];
+    }
+    if (response.contentType)
+      responseHeaders['content-type'] = response.contentType;
+    if (responseBody && !('content-length' in responseHeaders))
+      responseHeaders['content-length'] = String(Buffer.byteLength(responseBody));
+
+    await this._client.send('Fetch.fulfillRequest', {
+      requestId: this._interceptionId,
+      responseCode: response.status || 200,
+      responsePhrase: STATUS_TEXTS[response.status || 200],
+      responseHeaders: headersArray(responseHeaders),
+      body: responseBody ? responseBody.toString('base64') : undefined,
+    }).catch(error => {
+      // In certain cases, protocol will return error if the request was already canceled
+      // or the page was closed. We should tolerate these errors.
+      debugError(error);
+    });
+  }
+
+  async abort(errorCode: string = 'failed') {
+    // Request interception is not supported for data: urls.
+    if (this._url.startsWith('data:'))
+      return;
+    const errorReason = errorReasons[errorCode];
+    assert(errorReason, 'Unknown error code: ' + errorCode);
+    assert(this._allowInterception, 'Request Interception is not enabled!');
+    assert(!this._interceptionHandled, 'Request is already handled!');
+    this._interceptionHandled = true;
+    await this._client.send('Fetch.failRequest', {
+      requestId: this._interceptionId,
+      errorReason
+    }).catch(error => {
+      // In certain cases, protocol will return error if the request was already canceled
+      // or the page was closed. We should tolerate these errors.
+      debugError(error);
+    });
+  }
+}
+
+const errorReasons = {
+  'aborted': 'Aborted',
+  'accessdenied': 'AccessDenied',
+  'addressunreachable': 'AddressUnreachable',
+  'blockedbyclient': 'BlockedByClient',
+  'blockedbyresponse': 'BlockedByResponse',
+  'connectionaborted': 'ConnectionAborted',
+  'connectionclosed': 'ConnectionClosed',
+  'connectionfailed': 'ConnectionFailed',
+  'connectionrefused': 'ConnectionRefused',
+  'connectionreset': 'ConnectionReset',
+  'internetdisconnected': 'InternetDisconnected',
+  'namenotresolved': 'NameNotResolved',
+  'timedout': 'TimedOut',
+  'failed': 'Failed',
+};
+
+export class Response {
+  _bodyLoadedPromiseFulfill: any;
+  private _client: CDPSession;
+  private _request: Request;
+  private _contentPromise: Promise<Buffer> | null = null;
+  private _bodyLoadedPromise: Promise<Error | null>;
+  private _remoteAddress: { ip: string; port: number; };
+  private _status: number;
+  private _statusText: string;
+  private _url: string;
+  private _fromDiskCache: boolean;
+  private _fromServiceWorker: boolean;
+  private _headers: {[key: string]: string} = {};
+  private _securityDetails: SecurityDetails;
+
+  constructor(client: CDPSession, request: Request, responsePayload: Protocol.Network.Response) {
+    this._client = client;
+    this._request = request;
+
+    this._bodyLoadedPromise = new Promise(fulfill => {
+      this._bodyLoadedPromiseFulfill = fulfill;
+    });
+
+    this._remoteAddress = {
+      ip: responsePayload.remoteIPAddress,
+      port: responsePayload.remotePort,
+    };
+    this._status = responsePayload.status;
+    this._statusText = responsePayload.statusText;
+    this._url = request.url();
+    this._fromDiskCache = !!responsePayload.fromDiskCache;
+    this._fromServiceWorker = !!responsePayload.fromServiceWorker;
+    for (const key of Object.keys(responsePayload.headers))
+      this._headers[key.toLowerCase()] = responsePayload.headers[key];
+    this._securityDetails = responsePayload.securityDetails ? new SecurityDetails(responsePayload.securityDetails) : null;
+  }
+
+  remoteAddress(): { ip: string; port: number; } {
+    return this._remoteAddress;
+  }
+
+  url(): string {
+    return this._url;
+  }
+
+  ok(): boolean {
+    return this._status === 0 || (this._status >= 200 && this._status <= 299);
+  }
+
+  status(): number {
+    return this._status;
+  }
+
+  statusText(): string {
+    return this._statusText;
+  }
+
+  headers(): object {
+    return this._headers;
+  }
+
+  securityDetails(): SecurityDetails | null {
+    return this._securityDetails;
+  }
+
+  buffer(): Promise<Buffer> {
+    if (!this._contentPromise) {
+      this._contentPromise = this._bodyLoadedPromise.then(async error => {
+        if (error)
+          throw error;
+        const response = await this._client.send('Network.getResponseBody', {
+          requestId: this._request._requestId
+        });
+        return Buffer.from(response.body, response.base64Encoded ? 'base64' : 'utf8');
+      });
+    }
+    return this._contentPromise;
+  }
+
+  async text(): Promise<string> {
+    const content = await this.buffer();
+    return content.toString('utf8');
+  }
+
+  async json(): Promise<object> {
+    const content = await this.text();
+    return JSON.parse(content);
+  }
+
+  request(): Request {
+    return this._request;
+  }
+
+  fromCache(): boolean {
+    return this._fromDiskCache || this._request._fromMemoryCache;
+  }
+
+  fromServiceWorker(): boolean {
+    return this._fromServiceWorker;
+  }
+
+  frame(): Frame | null {
+    return this._request.frame();
+  }
+}
+
+export class SecurityDetails {
+  private _subjectName: string;
+  private _issuer: string;
+  private _validFrom: number;
+  private _validTo: number;
+  private _protocol: string;
+
+  constructor(securityPayload: Protocol.Network.SecurityDetails) {
+    this._subjectName = securityPayload['subjectName'];
+    this._issuer = securityPayload['issuer'];
+    this._validFrom = securityPayload['validFrom'];
+    this._validTo = securityPayload['validTo'];
+    this._protocol = securityPayload['protocol'];
+  }
+
+  subjectName(): string {
+    return this._subjectName;
+  }
+
+  issuer(): string {
+    return this._issuer;
+  }
+
+  validFrom(): number {
+    return this._validFrom;
+  }
+
+  validTo(): number {
+    return this._validTo;
+  }
+
+  protocol(): string {
+    return this._protocol;
+  }
+}
+
+function headersArray(headers: { [s: string]: string; }): { name: string; value: string; }[] {
+  const result = [];
+  for (const name in headers) {
+    if (!Object.is(headers[name], undefined))
+      result.push({name, value: headers[name] + ''});
+  }
+  return result;
+}
+
+// List taken from https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml with extra 306 and 418 codes.
+const STATUS_TEXTS = {
+  '100': 'Continue',
+  '101': 'Switching Protocols',
+  '102': 'Processing',
+  '103': 'Early Hints',
+  '200': 'OK',
+  '201': 'Created',
+  '202': 'Accepted',
+  '203': 'Non-Authoritative Information',
+  '204': 'No Content',
+  '205': 'Reset Content',
+  '206': 'Partial Content',
+  '207': 'Multi-Status',
+  '208': 'Already Reported',
+  '226': 'IM Used',
+  '300': 'Multiple Choices',
+  '301': 'Moved Permanently',
+  '302': 'Found',
+  '303': 'See Other',
+  '304': 'Not Modified',
+  '305': 'Use Proxy',
+  '306': 'Switch Proxy',
+  '307': 'Temporary Redirect',
+  '308': 'Permanent Redirect',
+  '400': 'Bad Request',
+  '401': 'Unauthorized',
+  '402': 'Payment Required',
+  '403': 'Forbidden',
+  '404': 'Not Found',
+  '405': 'Method Not Allowed',
+  '406': 'Not Acceptable',
+  '407': 'Proxy Authentication Required',
+  '408': 'Request Timeout',
+  '409': 'Conflict',
+  '410': 'Gone',
+  '411': 'Length Required',
+  '412': 'Precondition Failed',
+  '413': 'Payload Too Large',
+  '414': 'URI Too Long',
+  '415': 'Unsupported Media Type',
+  '416': 'Range Not Satisfiable',
+  '417': 'Expectation Failed',
+  '418': 'I\'m a teapot',
+  '421': 'Misdirected Request',
+  '422': 'Unprocessable Entity',
+  '423': 'Locked',
+  '424': 'Failed Dependency',
+  '425': 'Too Early',
+  '426': 'Upgrade Required',
+  '428': 'Precondition Required',
+  '429': 'Too Many Requests',
+  '431': 'Request Header Fields Too Large',
+  '451': 'Unavailable For Legal Reasons',
+  '500': 'Internal Server Error',
+  '501': 'Not Implemented',
+  '502': 'Bad Gateway',
+  '503': 'Service Unavailable',
+  '504': 'Gateway Timeout',
+  '505': 'HTTP Version Not Supported',
+  '506': 'Variant Also Negotiates',
+  '507': 'Insufficient Storage',
+  '508': 'Loop Detected',
+  '510': 'Not Extended',
+  '511': 'Network Authentication Required',
+};
--- a/src/chromium/Page.ts
+++ b/src/chromium/Page.ts
--- a/src/chromium/PipeTransport.ts
+++ b/src/chromium/PipeTransport.ts
@ -0,0 +1,73 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { ConnectionTransport } from '../ConnectionTransport';
+import { debugError, helper, RegisteredListener } from '../helper';
+
+export class PipeTransport implements ConnectionTransport {
+  private _pipeWrite: NodeJS.WritableStream;
+  private _pendingMessage = '';
+  private _eventListeners: RegisteredListener[];
+  onmessage?: (message: string) => void;
+  onclose?: () => void;
+
+  constructor(pipeWrite: NodeJS.WritableStream, pipeRead: NodeJS.ReadableStream) {
+    this._pipeWrite = pipeWrite;
+    this._eventListeners = [
+      helper.addEventListener(pipeRead, 'data', buffer => this._dispatch(buffer)),
+      helper.addEventListener(pipeRead, 'close', () => {
+        if (this.onclose)
+          this.onclose.call(null);
+      }),
+      helper.addEventListener(pipeRead, 'error', debugError),
+      helper.addEventListener(pipeWrite, 'error', debugError),
+    ];
+    this.onmessage = null;
+    this.onclose = null;
+  }
+
+  send(message: string) {
+    this._pipeWrite.write(message);
+    this._pipeWrite.write('\0');
+  }
+
+  _dispatch(buffer: Buffer) {
+    let end = buffer.indexOf('\0');
+    if (end === -1) {
+      this._pendingMessage += buffer.toString();
+      return;
+    }
+    const message = this._pendingMessage + buffer.toString(undefined, 0, end);
+    if (this.onmessage)
+      this.onmessage.call(null, message);
+
+    let start = end + 1;
+    end = buffer.indexOf('\0', start);
+    while (end !== -1) {
+      if (this.onmessage)
+        this.onmessage.call(null, buffer.toString(undefined, start, end));
+      start = end + 1;
+      end = buffer.indexOf('\0', start);
+    }
+    this._pendingMessage = buffer.toString(undefined, start);
+  }
+
+  close() {
+    this._pipeWrite = null;
+    helper.removeEventListeners(this._eventListeners);
+  }
+}
--- a/src/chromium/Playwright.ts
+++ b/src/chromium/Playwright.ts
@ -0,0 +1,66 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { Browser } from './Browser';
+import { BrowserFetcher, BrowserFetcherOptions } from './BrowserFetcher';
+import { ConnectionTransport } from '../ConnectionTransport';
+import { DeviceDescriptors } from '../DeviceDescriptors';
+import * as Errors from '../Errors';
+import { Launcher, LauncherBrowserOptions, LauncherChromeArgOptions, LauncherLaunchOptions } from './Launcher';
+
+export class Playwright {
+  private _projectRoot: string;
+  private _launcher: Launcher;
+
+  constructor(projectRoot: string, preferredRevision: string, isPlaywrightCore: boolean) {
+    this._projectRoot = projectRoot;
+    this._launcher = new Launcher(projectRoot, preferredRevision, isPlaywrightCore);
+  }
+
+  launch(options: (LauncherLaunchOptions & LauncherChromeArgOptions & LauncherBrowserOptions) | undefined): Promise<Browser> {
+    return this._launcher.launch(options);
+  }
+
+  connect(options: (LauncherBrowserOptions & {
+      browserWSEndpoint?: string;
+      browserURL?: string;
+      transport?: ConnectionTransport; })): Promise<Browser> {
+    return this._launcher.connect(options);
+  }
+
+  executablePath(): string {
+    return this._launcher.executablePath();
+  }
+
+  get devices(): any {
+    const result = DeviceDescriptors.slice();
+    for (const device of DeviceDescriptors)
+      result[device.name] = device;
+    return result;
+  }
+
+  get errors(): any {
+    return Errors;
+  }
+
+  defaultArgs(options: LauncherChromeArgOptions | undefined): string[] {
+    return this._launcher.defaultArgs(options);
+  }
+
+  createBrowserFetcher(options: BrowserFetcherOptions | undefined): BrowserFetcher {
+    return new BrowserFetcher(this._projectRoot, options);
+  }
+}
--- a/src/chromium/Target.ts
+++ b/src/chromium/Target.ts
@ -0,0 +1,134 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Events } from '../Events';
+import { Browser } from './Browser';
+import { BrowserContext } from './BrowserContext';
+import { CDPSession } from './Connection';
+import { Page, Viewport } from './Page';
+import { TaskQueue } from './TaskQueue';
+import { Worker } from './Worker';
+import { Protocol } from './protocol';
+
+export class Target {
+  private _targetInfo: Protocol.Target.TargetInfo;
+  private _browserContext: BrowserContext;
+  _targetId: string;
+  private _sessionFactory: () => Promise<CDPSession>;
+  private _ignoreHTTPSErrors: boolean;
+  private _defaultViewport: Viewport;
+  private _screenshotTaskQueue: TaskQueue;
+  private _pagePromise: Promise<Page> | null = null;
+  private _workerPromise: Promise<Worker> | null = null;
+  _initializedPromise: Promise<boolean>;
+  _initializedCallback: (value?: unknown) => void;
+  _isClosedPromise: Promise<void>;
+  _closedCallback: (value?: unknown) => void;
+  _isInitialized: boolean;
+
+  constructor(
+    targetInfo: Protocol.Target.TargetInfo,
+    browserContext: BrowserContext,
+    sessionFactory: () => Promise<CDPSession>,
+    ignoreHTTPSErrors: boolean,
+    defaultViewport: Viewport | null,
+    screenshotTaskQueue: TaskQueue) {
+    this._targetInfo = targetInfo;
+    this._browserContext = browserContext;
+    this._targetId = targetInfo.targetId;
+    this._sessionFactory = sessionFactory;
+    this._ignoreHTTPSErrors = ignoreHTTPSErrors;
+    this._defaultViewport = defaultViewport;
+    this._screenshotTaskQueue = screenshotTaskQueue;
+    this._initializedPromise = new Promise(fulfill => this._initializedCallback = fulfill).then(async success => {
+      if (!success)
+        return false;
+      const opener = this.opener();
+      if (!opener || !opener._pagePromise || this.type() !== 'page')
+        return true;
+      const openerPage = await opener._pagePromise;
+      if (!openerPage.listenerCount(Events.Page.Popup))
+        return true;
+      const popupPage = await this.page();
+      openerPage.emit(Events.Page.Popup, popupPage);
+      return true;
+    });
+    this._isClosedPromise = new Promise(fulfill => this._closedCallback = fulfill);
+    this._isInitialized = this._targetInfo.type !== 'page' || this._targetInfo.url !== '';
+    if (this._isInitialized)
+      this._initializedCallback(true);
+  }
+
+  createCDPSession(): Promise<CDPSession> {
+    return this._sessionFactory();
+  }
+
+  async page(): Promise<Page | null> {
+    if ((this._targetInfo.type === 'page' || this._targetInfo.type === 'background_page') && !this._pagePromise) {
+      this._pagePromise = this._sessionFactory()
+          .then(client => Page.create(client, this, this._ignoreHTTPSErrors, this._defaultViewport, this._screenshotTaskQueue));
+    }
+    return this._pagePromise;
+  }
+
+  async worker(): Promise<Worker | null> {
+    if (this._targetInfo.type !== 'service_worker' && this._targetInfo.type !== 'shared_worker')
+      return null;
+    if (!this._workerPromise) {
+      // TODO(einbinder): Make workers send their console logs.
+      this._workerPromise = this._sessionFactory()
+          .then(client => new Worker(client, this._targetInfo.url, () => {} /* consoleAPICalled */, () => {} /* exceptionThrown */));
+    }
+    return this._workerPromise;
+  }
+
+  url(): string {
+    return this._targetInfo.url;
+  }
+
+  type(): 'page' | 'background_page' | 'service_worker' | 'shared_worker' | 'other' | 'browser' {
+    const type = this._targetInfo.type;
+    if (type === 'page' || type === 'background_page' || type === 'service_worker' || type === 'shared_worker' || type === 'browser')
+      return type;
+    return 'other';
+  }
+
+  browser(): Browser {
+    return this._browserContext.browser();
+  }
+
+  browserContext(): BrowserContext {
+    return this._browserContext;
+  }
+
+  opener(): Target | null {
+    const { openerId } = this._targetInfo;
+    if (!openerId)
+      return null;
+    return this.browser()._targets.get(openerId);
+  }
+
+  _targetInfoChanged(targetInfo: Protocol.Target.TargetInfo) {
+    this._targetInfo = targetInfo;
+
+    if (!this._isInitialized && (this._targetInfo.type !== 'page' || this._targetInfo.url !== '')) {
+      this._isInitialized = true;
+      this._initializedCallback(true);
+      return;
+    }
+  }
+}
--- a/src/chromium/TaskQueue.ts
+++ b/src/chromium/TaskQueue.ts
@ -0,0 +1,30 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class TaskQueue {
+  private _chain: Promise<any>;
+
+  constructor() {
+    this._chain = Promise.resolve();
+  }
+
+  postTask(task: () => any): Promise<any> {
+    const result = this._chain.then(task);
+    this._chain = result.catch(() => {});
+    return result;
+  }
+}
--- a/src/chromium/Tracing.ts
+++ b/src/chromium/Tracing.ts
@ -0,0 +1,66 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { CDPSession } from './Connection';
+import { assert } from '../helper';
+import { readProtocolStream } from './protocolHelper';
+
+export class Tracing {
+  private _client: CDPSession;
+  private _recording = false;
+  private _path = '';
+
+  constructor(client: CDPSession) {
+    this._client = client;
+  }
+
+  async start(options: { path?: string; screenshots?: boolean; categories?: string[]; } = {}) {
+    assert(!this._recording, 'Cannot start recording trace while already recording trace.');
+
+    const defaultCategories = [
+      '-*', 'devtools.timeline', 'v8.execute', 'disabled-by-default-devtools.timeline',
+      'disabled-by-default-devtools.timeline.frame', 'toplevel',
+      'blink.console', 'blink.user_timing', 'latencyInfo', 'disabled-by-default-devtools.timeline.stack',
+      'disabled-by-default-v8.cpu_profiler', 'disabled-by-default-v8.cpu_profiler.hires'
+    ];
+    const {
+      path = null,
+      screenshots = false,
+      categories = defaultCategories,
+    } = options;
+
+    if (screenshots)
+      categories.push('disabled-by-default-devtools.screenshot');
+
+    this._path = path;
+    this._recording = true;
+    await this._client.send('Tracing.start', {
+      transferMode: 'ReturnAsStream',
+      categories: categories.join(',')
+    });
+  }
+
+  async stop(): Promise<Buffer> {
+    let fulfill: (buffer: Buffer) => void;
+    const contentPromise = new Promise<Buffer>(x => fulfill = x);
+    this._client.once('Tracing.tracingComplete', event => {
+      readProtocolStream(this._client, event.stream, this._path).then(fulfill);
+    });
+    await this._client.send('Tracing.end');
+    this._recording = false;
+    return contentPromise;
+  }
+}
--- a/src/chromium/WebSocketTransport.ts
+++ b/src/chromium/WebSocketTransport.ts
@ -0,0 +1,58 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as WebSocket from 'ws';
+import { ConnectionTransport } from '../ConnectionTransport';
+
+export class WebSocketTransport implements ConnectionTransport {
+  private _ws: WebSocket;
+  onmessage?: (message: string) => void;
+  onclose?: () => void;
+
+  static create(url: string): Promise<WebSocketTransport> {
+    return new Promise((resolve, reject) => {
+      const ws = new WebSocket(url, [], {
+        perMessageDeflate: false,
+        maxPayload: 256 * 1024 * 1024, // 256Mb
+      });
+      ws.addEventListener('open', () => resolve(new WebSocketTransport(ws)));
+      ws.addEventListener('error', reject);
+    });
+  }
+
+  constructor(ws: WebSocket) {
+    this._ws = ws;
+    this._ws.addEventListener('message', event => {
+      if (this.onmessage)
+        this.onmessage.call(null, event.data);
+    });
+    this._ws.addEventListener('close', event => {
+      if (this.onclose)
+        this.onclose.call(null);
+    });
+    // Silently ignore all errors - we don't know what to do with them.
+    this._ws.addEventListener('error', () => {});
+  }
+
+  send(message: string) {
+    this._ws.send(message);
+  }
+
+  close() {
+    this._ws.close();
+  }
+}
--- a/src/chromium/Worker.ts
+++ b/src/chromium/Worker.ts
@ -0,0 +1,63 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { EventEmitter } from 'events';
+import { CDPSession } from './Connection';
+import { ExecutionContext } from './ExecutionContext';
+import { debugError } from '../helper';
+import { JSHandle } from './JSHandle';
+import { Protocol } from './protocol';
+
+export class Worker extends EventEmitter {
+  private _client: CDPSession;
+  private _url: string;
+  private _executionContextPromise: Promise<ExecutionContext>;
+  private _executionContextCallback: (value?: ExecutionContext) => void;
+
+  constructor(client: CDPSession, url: string, consoleAPICalled: (arg0: string, arg1: JSHandle[], arg2: Protocol.Runtime.StackTrace | undefined) => void, exceptionThrown: (arg0: Protocol.Runtime.ExceptionDetails) => void) {
+    super();
+    this._client = client;
+    this._url = url;
+    this._executionContextPromise = new Promise(x => this._executionContextCallback = x);
+    let jsHandleFactory: (o: Protocol.Runtime.RemoteObject) => JSHandle;
+    this._client.once('Runtime.executionContextCreated', async event => {
+      jsHandleFactory = remoteObject => new JSHandle(executionContext, client, remoteObject);
+      const executionContext = new ExecutionContext(client, event.context, null);
+      this._executionContextCallback(executionContext);
+    });
+    // This might fail if the target is closed before we recieve all execution contexts.
+    this._client.send('Runtime.enable', {}).catch(debugError);
+
+    this._client.on('Runtime.consoleAPICalled', event => consoleAPICalled(event.type, event.args.map(jsHandleFactory), event.stackTrace));
+    this._client.on('Runtime.exceptionThrown', exception => exceptionThrown(exception.exceptionDetails));
+  }
+
+  url(): string {
+    return this._url;
+  }
+
+  async executionContext(): Promise<ExecutionContext> {
+    return this._executionContextPromise;
+  }
+
+  async evaluate(pageFunction: Function | string, ...args: any[]): Promise<any> {
+    return (await this._executionContextPromise).evaluate(pageFunction, ...args);
+  }
+
+  async evaluateHandle(pageFunction: Function | string, ...args: any[]): Promise<JSHandle> {
+    return (await this._executionContextPromise).evaluateHandle(pageFunction, ...args);
+  }
+}
--- a/src/chromium/protocolHelper.ts
+++ b/src/chromium/protocolHelper.ts
@ -0,0 +1,97 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import * as fs from 'fs';
+import {helper, assert, debugError} from '../helper';
+import { CDPSession } from './Connection';
+import { Protocol } from './protocol';
+
+const openAsync = helper.promisify(fs.open);
+const writeAsync = helper.promisify(fs.write);
+const closeAsync = helper.promisify(fs.close);
+
+
+export function getExceptionMessage(exceptionDetails: Protocol.Runtime.ExceptionDetails): string {
+  if (exceptionDetails.exception)
+    return exceptionDetails.exception.description || exceptionDetails.exception.value;
+  let message = exceptionDetails.text;
+  if (exceptionDetails.stackTrace) {
+    for (const callframe of exceptionDetails.stackTrace.callFrames) {
+      const location = callframe.url + ':' + callframe.lineNumber + ':' + callframe.columnNumber;
+      const functionName = callframe.functionName || '<anonymous>';
+      message += `\n    at ${functionName} (${location})`;
+    }
+  }
+  return message;
+}
+
+export function valueFromRemoteObject(remoteObject: Protocol.Runtime.RemoteObject): any {
+  assert(!remoteObject.objectId, 'Cannot extract value when objectId is given');
+  if (remoteObject.unserializableValue) {
+    if (remoteObject.type === 'bigint' && typeof BigInt !== 'undefined')
+      return BigInt(remoteObject.unserializableValue.replace('n', ''));
+    switch (remoteObject.unserializableValue) {
+      case '-0':
+        return -0;
+      case 'NaN':
+        return NaN;
+      case 'Infinity':
+        return Infinity;
+      case '-Infinity':
+        return -Infinity;
+      default:
+        throw new Error('Unsupported unserializable value: ' + remoteObject.unserializableValue);
+    }
+  }
+  return remoteObject.value;
+}
+
+export async function releaseObject(client: CDPSession, remoteObject: Protocol.Runtime.RemoteObject) {
+  if (!remoteObject.objectId)
+    return;
+  await client.send('Runtime.releaseObject', {objectId: remoteObject.objectId}).catch(error => {
+    // Exceptions might happen in case of a page been navigated or closed.
+    // Swallow these since they are harmless and we don't leak anything in this case.
+    debugError(error);
+  });
+}
+
+export async function readProtocolStream(client: CDPSession, handle: string, path: string | null): Promise<Buffer> {
+  let eof = false;
+  let file;
+  if (path)
+    file = await openAsync(path, 'w');
+  const bufs = [];
+  while (!eof) {
+    const response = await client.send('IO.read', {handle});
+    eof = response.eof;
+    const buf = Buffer.from(response.data, response.base64Encoded ? 'base64' : undefined);
+    bufs.push(buf);
+    if (path)
+      await writeAsync(file, buf);
+  }
+  if (path)
+    await closeAsync(file);
+  await client.send('IO.close', {handle});
+  let resultBuffer = null;
+  try {
+    resultBuffer = Buffer.concat(bufs);
+  } finally {
+    return resultBuffer;
+  }
+}
+
+
--- a/src/firefox/Accessibility.ts
+++ b/src/firefox/Accessibility.ts
@ -0,0 +1,273 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+interface SerializedAXNode {
+  role: string;
+
+  name?: string;
+  value?: string|number;
+  description?: string;
+
+  keyshortcuts?: string;
+  roledescription?: string;
+  valuetext?: string;
+
+  disabled?: boolean;
+  expanded?: boolean;
+  focused?: boolean;
+  modal?: boolean;
+  multiline?: boolean;
+  multiselectable?: boolean;
+  readonly?: boolean;
+  required?: boolean;
+  selected?: boolean;
+
+  checked?: boolean|'mixed';
+  pressed?: boolean|'mixed';
+
+  level?: number;
+
+  autocomplete?: string;
+  haspopup?: string;
+  invalid?: string;
+  orientation?: string;
+
+  children?: Array<SerializedAXNode>;
+}
+export class Accessibility {
+  _session: any;
+  constructor(session) {
+    this._session = session;
+  }
+  async snapshot(options: { interestingOnly?: boolean; } | undefined = {}): Promise<SerializedAXNode> {
+    const { interestingOnly = true } = options;
+    const { tree } = await this._session.send('Accessibility.getFullAXTree');
+    const root = new AXNode(tree);
+    if (!interestingOnly)
+      return serializeTree(root)[0];
+    const interestingNodes: Set<AXNode> = new Set();
+    collectInterestingNodes(interestingNodes, root, false);
+    return serializeTree(root, interestingNodes)[0];
+  }
+}
+function collectInterestingNodes(collection: Set<AXNode>, node: AXNode, insideControl: boolean) {
+  if (node.isInteresting(insideControl))
+    collection.add(node);
+  if (node.isLeafNode())
+    return;
+  insideControl = insideControl || node.isControl();
+  for (const child of node._children)
+    collectInterestingNodes(collection, child, insideControl);
+}
+function serializeTree(node: AXNode, whitelistedNodes?: Set<AXNode>): Array<SerializedAXNode> {
+  const children: Array<SerializedAXNode> = [];
+  for (const child of node._children)
+    children.push(...serializeTree(child, whitelistedNodes));
+  if (whitelistedNodes && !whitelistedNodes.has(node))
+    return children;
+  const serializedNode = node.serialize();
+  if (children.length)
+    serializedNode.children = children;
+  return [serializedNode];
+}
+class AXNode {
+  _children: AXNode[];
+  private _payload: any;
+  private _editable: boolean;
+  private _richlyEditable: boolean;
+  private _focusable: boolean;
+  private _expanded: boolean;
+  private _name: string;
+  private _role: string;
+  private _cachedHasFocusableChild: boolean|undefined;
+  constructor(payload) {
+    this._payload = payload;
+    this._children = (payload.children || []).map(x => new AXNode(x));
+    this._editable = payload.editable;
+    this._richlyEditable = this._editable && (payload.tag !== 'textarea' && payload.tag !== 'input');
+    this._focusable = payload.focusable;
+    this._expanded = payload.expanded;
+    this._name = this._payload.name;
+    this._role = this._payload.role;
+    this._cachedHasFocusableChild;
+  }
+  _isPlainTextField(): boolean {
+    if (this._richlyEditable)
+      return false;
+    if (this._editable)
+      return true;
+    return this._role === 'entry';
+  }
+  _isTextOnlyObject(): boolean {
+    const role = this._role;
+    return (role === 'text leaf' || role === 'text' || role === 'statictext');
+  }
+  _hasFocusableChild(): boolean {
+    if (this._cachedHasFocusableChild === undefined) {
+      this._cachedHasFocusableChild = false;
+      for (const child of this._children) {
+        if (child._focusable || child._hasFocusableChild()) {
+          this._cachedHasFocusableChild = true;
+          break;
+        }
+      }
+    }
+    return this._cachedHasFocusableChild;
+  }
+  isLeafNode(): boolean {
+    if (!this._children.length)
+      return true;
+      // These types of objects may have children that we use as internal
+      // implementation details, but we want to expose them as leaves to platform
+      // accessibility APIs because screen readers might be confused if they find
+      // any children.
+    if (this._isPlainTextField() || this._isTextOnlyObject())
+      return true;
+      // Roles whose children are only presentational according to the ARIA and
+      // HTML5 Specs should be hidden from screen readers.
+      // (Note that whilst ARIA buttons can have only presentational children, HTML5
+      // buttons are allowed to have content.)
+    switch (this._role) {
+      case 'graphic':
+      case 'scrollbar':
+      case 'slider':
+      case 'separator':
+      case 'progressbar':
+        return true;
+      default:
+        break;
+    }
+    // Here and below: Android heuristics
+    if (this._hasFocusableChild())
+      return false;
+    if (this._focusable && this._name)
+      return true;
+    if (this._role === 'heading' && this._name)
+      return true;
+    return false;
+  }
+  isControl(): boolean {
+    switch (this._role) {
+      case 'checkbutton':
+      case 'check menu item':
+      case 'check rich option':
+      case 'combobox':
+      case 'combobox option':
+      case 'color chooser':
+      case 'listbox':
+      case 'listbox option':
+      case 'listbox rich option':
+      case 'popup menu':
+      case 'menupopup':
+      case 'menuitem':
+      case 'menubar':
+      case 'button':
+      case 'pushbutton':
+      case 'radiobutton':
+      case 'radio menuitem':
+      case 'scrollbar':
+      case 'slider':
+      case 'spinbutton':
+      case 'switch':
+      case 'pagetab':
+      case 'entry':
+      case 'tree table':
+        return true;
+      default:
+        return false;
+    }
+  }
+  isInteresting(insideControl: boolean): boolean {
+    if (this._focusable || this._richlyEditable)
+      return true;
+      // If it's not focusable but has a control role, then it's interesting.
+    if (this.isControl())
+      return true;
+      // A non focusable child of a control is not interesting
+    if (insideControl)
+      return false;
+    return this.isLeafNode() && !!this._name.trim();
+  }
+  serialize(): SerializedAXNode {
+    const node: {[x in keyof SerializedAXNode]: any} = {
+      role: this._role
+    };
+    const userStringProperties: Array<keyof SerializedAXNode> = [
+      'name',
+      'value',
+      'description',
+      'roledescription',
+      'valuetext',
+      'keyshortcuts',
+    ];
+    for (const userStringProperty of userStringProperties) {
+      if (!(userStringProperty in this._payload))
+        continue;
+      node[userStringProperty] = this._payload[userStringProperty];
+    }
+    const booleanProperties: Array<keyof SerializedAXNode> = [
+      'disabled',
+      'expanded',
+      'focused',
+      'modal',
+      'multiline',
+      'multiselectable',
+      'readonly',
+      'required',
+      'selected',
+    ];
+    for (const booleanProperty of booleanProperties) {
+      if (this._role === 'document' && booleanProperty === 'focused')
+        continue; // document focusing is strange
+      const value = this._payload[booleanProperty];
+      if (!value)
+        continue;
+      node[booleanProperty] = value;
+    }
+    const tristateProperties: Array<keyof SerializedAXNode> = [
+      'checked',
+      'pressed',
+    ];
+    for (const tristateProperty of tristateProperties) {
+      if (!(tristateProperty in this._payload))
+        continue;
+      const value = this._payload[tristateProperty];
+      node[tristateProperty] = value;
+    }
+    const numericalProperties: Array<keyof SerializedAXNode> = [
+      'level'
+    ];
+    for (const numericalProperty of numericalProperties) {
+      if (!(numericalProperty in this._payload))
+        continue;
+      node[numericalProperty] = this._payload[numericalProperty];
+    }
+    const tokenProperties: Array<keyof SerializedAXNode> = [
+      'autocomplete',
+      'haspopup',
+      'invalid',
+      'orientation',
+    ];
+    for (const tokenProperty of tokenProperties) {
+      const value = this._payload[tokenProperty];
+      if (!value || value === 'false')
+        continue;
+      node[tokenProperty] = value;
+    }
+    return node;
+  }
+}
--- a/src/firefox/Browser.ts
+++ b/src/firefox/Browser.ts
@ -0,0 +1,334 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {RegisteredListener, helper, assert} from '../helper';
+import {Page, Viewport} from './Page';
+import {EventEmitter} from 'events';
+import {Connection, ConnectionEvents} from './Connection';
+import {Events} from '../Events';
+
+export class Browser extends EventEmitter {
+  private _connection: Connection;
+  _defaultViewport: Viewport;
+  private _process: import('child_process').ChildProcess;
+  private _closeCallback: () => void;
+  _targets: Map<string, Target>;
+  private _defaultContext: BrowserContext;
+  private _contexts: Map<string, BrowserContext>;
+  private _eventListeners: RegisteredListener[];
+
+  static async create(connection: Connection, defaultViewport: Viewport | null, process: import('child_process').ChildProcess | null, closeCallback: () => void) {
+    const {browserContextIds} = await connection.send('Target.getBrowserContexts');
+    const browser = new Browser(connection, browserContextIds, defaultViewport, process, closeCallback);
+    await connection.send('Target.enable');
+    return browser;
+  }
+
+
+  constructor(connection: Connection, browserContextIds: Array<string>, defaultViewport: Viewport | null, process: import('child_process').ChildProcess | null, closeCallback: () => void) {
+    super();
+    this._connection = connection;
+    this._defaultViewport = defaultViewport;
+    this._process = process;
+    this._closeCallback = closeCallback;
+
+    this._targets = new Map();
+
+    this._defaultContext = new BrowserContext(this._connection, this, null);
+    this._contexts = new Map();
+    for (const browserContextId of browserContextIds)
+      this._contexts.set(browserContextId, new BrowserContext(this._connection, this, browserContextId));
+
+    this._connection.on(ConnectionEvents.Disconnected, () => this.emit(Events.Browser.Disconnected));
+
+    this._eventListeners = [
+      helper.addEventListener(this._connection, 'Target.targetCreated', this._onTargetCreated.bind(this)),
+      helper.addEventListener(this._connection, 'Target.targetDestroyed', this._onTargetDestroyed.bind(this)),
+      helper.addEventListener(this._connection, 'Target.targetInfoChanged', this._onTargetInfoChanged.bind(this)),
+    ];
+  }
+
+  wsEndpoint() {
+    return this._connection.url();
+  }
+
+  disconnect() {
+    this._connection.dispose();
+  }
+
+
+  isConnected(): boolean {
+    return !this._connection._closed;
+  }
+
+  async createIncognitoBrowserContext(): Promise<BrowserContext> {
+    const {browserContextId} = await this._connection.send('Target.createBrowserContext');
+    const context = new BrowserContext(this._connection, this, browserContextId);
+    this._contexts.set(browserContextId, context);
+    return context;
+  }
+
+
+  browserContexts(): Array<BrowserContext> {
+    return [this._defaultContext, ...Array.from(this._contexts.values())];
+  }
+
+  defaultBrowserContext() {
+    return this._defaultContext;
+  }
+
+  async _disposeContext(browserContextId) {
+    await this._connection.send('Target.removeBrowserContext', {browserContextId});
+    this._contexts.delete(browserContextId);
+  }
+
+
+  async userAgent(): Promise<string> {
+    const info = await this._connection.send('Browser.getInfo');
+    return info.userAgent;
+  }
+
+
+  async version(): Promise<string> {
+    const info = await this._connection.send('Browser.getInfo');
+    return info.version;
+  }
+
+
+  process(): import('child_process').ChildProcess | null {
+    return this._process;
+  }
+
+
+  async waitForTarget(predicate: (target: Target) => boolean, options: { timeout?: number; } = {}): Promise<Target> {
+    const {
+      timeout = 30000
+    } = options;
+    const existingTarget = this.targets().find(predicate);
+    if (existingTarget)
+      return existingTarget;
+    let resolve;
+    const targetPromise = new Promise<Target>(x => resolve = x);
+    this.on(Events.Browser.TargetCreated, check);
+    this.on('targetchanged', check);
+    try {
+      if (!timeout)
+        return await targetPromise;
+      return await helper.waitWithTimeout(targetPromise, 'target', timeout);
+    } finally {
+      this.removeListener(Events.Browser.TargetCreated, check);
+      this.removeListener('targetchanged', check);
+    }
+
+    function check(target: Target) {
+      if (predicate(target))
+        resolve(target);
+    }
+  }
+
+
+  newPage(): Promise<Page> {
+    return this._createPageInContext(this._defaultContext._browserContextId);
+  }
+
+
+  async _createPageInContext(browserContextId: string | null): Promise<Page> {
+    const {targetId} = await this._connection.send('Target.newPage', {
+      browserContextId: browserContextId || undefined
+    });
+    const target = this._targets.get(targetId);
+    return await target.page();
+  }
+
+  async pages() {
+    const pageTargets = Array.from(this._targets.values()).filter(target => target.type() === 'page');
+    return await Promise.all(pageTargets.map(target => target.page()));
+  }
+
+  targets() {
+    return Array.from(this._targets.values());
+  }
+
+  target() {
+    return this.targets().find(target => target.type() === 'browser');
+  }
+
+  async _onTargetCreated({targetId, url, browserContextId, openerId, type}) {
+    const context = browserContextId ? this._contexts.get(browserContextId) : this._defaultContext;
+    const target = new Target(this._connection, this, context, targetId, type, url, openerId);
+    this._targets.set(targetId, target);
+    if (target.opener() && target.opener()._pagePromise) {
+      const openerPage = await target.opener()._pagePromise;
+      if (openerPage.listenerCount(Events.Page.Popup)) {
+        const popupPage = await target.page();
+        openerPage.emit(Events.Page.Popup, popupPage);
+      }
+    }
+    this.emit(Events.Browser.TargetCreated, target);
+    context.emit(Events.BrowserContext.TargetCreated, target);
+  }
+
+  _onTargetDestroyed({targetId}) {
+    const target = this._targets.get(targetId);
+    this._targets.delete(targetId);
+    target._closedCallback();
+    this.emit(Events.Browser.TargetDestroyed, target);
+    target.browserContext().emit(Events.BrowserContext.TargetDestroyed, target);
+  }
+
+  _onTargetInfoChanged({targetId, url}) {
+    const target = this._targets.get(targetId);
+    target._url = url;
+    this.emit(Events.Browser.TargetChanged, target);
+    target.browserContext().emit(Events.BrowserContext.TargetChanged, target);
+  }
+
+  async close() {
+    helper.removeEventListeners(this._eventListeners);
+    await this._closeCallback();
+  }
+}
+
+export class Target {
+  _pagePromise?: Promise<Page>;
+  private _browser: Browser;
+  _context: BrowserContext;
+  private _connection: any;
+  private _targetId: string;
+  private _type: 'page' | 'browser';
+  _url: string;
+  private _openerId: string;
+  _isClosedPromise: Promise<unknown>;
+  _closedCallback: (value?: unknown) => void;
+
+  constructor(connection: any, browser: Browser, context: BrowserContext, targetId: string, type: 'page' | 'browser', url: string, openerId: string | undefined) {
+    this._browser = browser;
+    this._context = context;
+    this._connection = connection;
+    this._targetId = targetId;
+    this._type = type;
+    this._url = url;
+    this._openerId = openerId;
+    this._isClosedPromise = new Promise(fulfill => this._closedCallback = fulfill);
+  }
+
+
+  opener(): Target | null {
+    return this._openerId ? this._browser._targets.get(this._openerId) : null;
+  }
+
+
+  type(): 'page' | 'browser' {
+    return this._type;
+  }
+
+  url() {
+    return this._url;
+  }
+
+
+  browserContext(): BrowserContext {
+    return this._context;
+  }
+
+  async page() {
+    if (this._type === 'page' && !this._pagePromise) {
+      const session = await this._connection.createSession(this._targetId);
+      this._pagePromise = Page.create(session, this, this._browser._defaultViewport);
+    }
+    return this._pagePromise;
+  }
+
+  browser() {
+    return this._browser;
+  }
+}
+
+export class BrowserContext extends EventEmitter {
+  _connection: Connection;
+  _browser: Browser;
+  _browserContextId: string;
+
+  constructor(connection: Connection, browser: Browser, browserContextId: string | null) {
+    super();
+    this._connection = connection;
+    this._browser = browser;
+    this._browserContextId = browserContextId;
+  }
+
+
+  async overridePermissions(origin: string, permissions: Array<string>) {
+    const webPermissionToProtocol = new Map([
+      ['geolocation', 'geo'],
+      ['microphone', 'microphone'],
+      ['camera', 'camera'],
+      ['notifications', 'desktop-notifications'],
+    ]);
+    permissions = permissions.map(permission => {
+      const protocolPermission = webPermissionToProtocol.get(permission);
+      if (!protocolPermission)
+        throw new Error('Unknown permission: ' + permission);
+      return protocolPermission;
+    });
+    await this._connection.send('Browser.grantPermissions', {origin, browserContextId: this._browserContextId || undefined, permissions});
+  }
+
+  async clearPermissionOverrides() {
+    await this._connection.send('Browser.resetPermissions', {browserContextId: this._browserContextId || undefined});
+  }
+
+
+  targets(): Array<Target> {
+    return this._browser.targets().filter(target => target.browserContext() === this);
+  }
+
+
+  async pages(): Promise<Array<Page>> {
+    const pages = await Promise.all(
+        this.targets()
+            .filter(target => target.type() === 'page')
+            .map(target => target.page())
+    );
+    return pages.filter(page => !!page);
+  }
+
+
+  waitForTarget(predicate: (arg0: Target) => boolean, options: { timeout?: number; } | undefined): Promise<Target> {
+    return this._browser.waitForTarget(target => target.browserContext() === this && predicate(target), options);
+  }
+
+
+  isIncognito(): boolean {
+    return !!this._browserContextId;
+  }
+
+  newPage() {
+    return this._browser._createPageInContext(this._browserContextId);
+  }
+
+
+  browser(): Browser {
+    return this._browser;
+  }
+
+  async close() {
+    assert(this._browserContextId, 'Non-incognito contexts cannot be closed!');
+    await this._browser._disposeContext(this._browserContextId);
+  }
+}
+
+module.exports = {Browser, BrowserContext, Target};
--- a/src/firefox/BrowserFetcher.ts
+++ b/src/firefox/BrowserFetcher.ts
@ -0,0 +1,283 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as os from 'os';
+import * as fs from 'fs';
+import * as path from 'path';
+import * as extract from 'extract-zip';
+import * as util from 'util';
+import * as URL from 'url';
+import {helper, assert} from '../helper';
+import * as removeRecursive from 'rimraf';
+// @ts-ignore
+import * as ProxyAgent from 'https-proxy-agent';
+// @ts-ignore
+import {getProxyForUrl} from 'proxy-from-env';
+const DEFAULT_DOWNLOAD_HOST = 'https://playwrightaccount.blob.core.windows.net/builds';
+
+const downloadURLs = {
+  chromium: {
+    linux: '%s/chromium-browser-snapshots/Linux_x64/%s/%s.zip',
+    mac: '%s/chromium-browser-snapshots/Mac/%s/%s.zip',
+    win32: '%s/chromium-browser-snapshots/Win/%s/%s.zip',
+    win64: '%s/chromium-browser-snapshots/Win_x64/%s/%s.zip',
+  },
+  firefox: {
+    linux: '%s/firefox/%s/%s.zip',
+    mac: '%s/firefox/%s/%s.zip',
+    win32: '%s/firefox/%s/%s.zip',
+    win64: '%s/firefox/%s/%s.zip',
+  },
+};
+
+function archiveName(product: string, platform: string, revision: string): string {
+  if (product === 'chromium') {
+    if (platform === 'linux')
+      return 'chrome-linux';
+    if (platform === 'mac')
+      return 'chrome-mac';
+    if (platform === 'win32' || platform === 'win64') {
+      // Windows archive name changed at r591479.
+      return parseInt(revision, 10) > 591479 ? 'chrome-win' : 'chrome-win32';
+    }
+  } else if (product === 'firefox') {
+    if (platform === 'linux')
+      return 'firefox-linux';
+    if (platform === 'mac')
+      return 'firefox-mac';
+    if (platform === 'win32' || platform === 'win64')
+      return 'firefox-' + platform;
+  }
+  return null;
+}
+
+function downloadURL(product: string, platform: string, host: string, revision: string): string {
+  return util.format(downloadURLs[product][platform], host, revision, archiveName(product, platform, revision));
+}
+
+const readdirAsync = helper.promisify(fs.readdir.bind(fs));
+const mkdirAsync = helper.promisify(fs.mkdir.bind(fs));
+const unlinkAsync = helper.promisify(fs.unlink.bind(fs));
+const chmodAsync = helper.promisify(fs.chmod.bind(fs));
+
+function existsAsync(filePath) {
+  let fulfill = null;
+  const promise = new Promise(x => fulfill = x);
+  fs.access(filePath, err => fulfill(!err));
+  return promise;
+}
+
+export class BrowserFetcher {
+  _product: string;
+  _downloadsFolder: string;
+  _downloadHost: string;
+  _platform: string;
+  constructor(projectRoot: string, options: BrowserFetcherOptions | undefined = {}) {
+    this._product = (options.browser || 'chromium').toLowerCase();
+    assert(this._product === 'chromium' || this._product === 'firefox', `Unkown product: "${options.browser}"`);
+    this._downloadsFolder = options.path || path.join(projectRoot, '.local-browser');
+    this._downloadHost = options.host || DEFAULT_DOWNLOAD_HOST;
+    this._platform = options.platform || '';
+    if (!this._platform) {
+      const platform = os.platform();
+      if (platform === 'darwin')
+        this._platform = 'mac';
+      else if (platform === 'linux')
+        this._platform = 'linux';
+      else if (platform === 'win32')
+        this._platform = os.arch() === 'x64' ? 'win64' : 'win32';
+      assert(this._platform, 'Unsupported platform: ' + os.platform());
+    }
+    assert(downloadURLs[this._product][this._platform], 'Unsupported platform: ' + this._platform);
+  }
+
+  platform(): string {
+    return this._platform;
+  }
+
+  canDownload(revision: string): Promise<boolean> {
+    const url = downloadURL(this._product, this._platform, this._downloadHost, revision);
+    let resolve;
+    const promise = new Promise<boolean>(x => resolve = x);
+    const request = httpRequest(url, 'HEAD', response => {
+      resolve(response.statusCode === 200);
+    });
+    request.on('error', error => {
+      console.error(error);
+      resolve(false);
+    });
+    return promise;
+  }
+
+  async download(revision: string, progressCallback: ((arg0: number, arg1: number) => void) | null): Promise<RevisionInfo> {
+    const url = downloadURL(this._product, this._platform, this._downloadHost, revision);
+    const zipPath = path.join(this._downloadsFolder, `download-${this._product}-${this._platform}-${revision}.zip`);
+    const folderPath = this._getFolderPath(revision);
+    if (await existsAsync(folderPath))
+      return this.revisionInfo(revision);
+    if (!(await existsAsync(this._downloadsFolder)))
+      await mkdirAsync(this._downloadsFolder);
+    try {
+      await downloadFile(url, zipPath, progressCallback);
+      await extractZip(zipPath, folderPath);
+    } finally {
+      if (await existsAsync(zipPath))
+        await unlinkAsync(zipPath);
+    }
+    const revisionInfo = this.revisionInfo(revision);
+    if (revisionInfo)
+      await chmodAsync(revisionInfo.executablePath, 0o755);
+    return revisionInfo;
+  }
+
+  async localRevisions(): Promise<Array<string>> {
+    if (!await existsAsync(this._downloadsFolder))
+      return [];
+    const fileNames = await readdirAsync(this._downloadsFolder);
+    return fileNames.map(fileName => parseFolderPath(fileName)).filter(entry => entry && entry.platform === this._platform).map(entry => entry.revision);
+  }
+
+  async remove(revision: string) {
+    const folderPath = this._getFolderPath(revision);
+    assert(await existsAsync(folderPath), `Failed to remove: revision ${revision} is not downloaded`);
+    await new Promise(fulfill => removeRecursive(folderPath, fulfill));
+  }
+
+  revisionInfo(revision: string): RevisionInfo {
+    const folderPath = this._getFolderPath(revision);
+    let executablePath = '';
+    if (this._product === 'chromium') {
+      if (this._platform === 'mac')
+        executablePath = path.join(folderPath, archiveName(this._product, this._platform, revision), 'Chromium.app', 'Contents', 'MacOS', 'Chromium');
+      else if (this._platform === 'linux')
+        executablePath = path.join(folderPath, archiveName(this._product, this._platform, revision), 'chrome');
+      else if (this._platform === 'win32' || this._platform === 'win64')
+        executablePath = path.join(folderPath, archiveName(this._product, this._platform, revision), 'chrome.exe');
+      else
+        throw new Error('Unsupported platform: ' + this._platform);
+    } else if (this._product === 'firefox') {
+      if (this._platform === 'mac')
+        executablePath = path.join(folderPath, 'firefox', 'Nightly.app', 'Contents', 'MacOS', 'firefox');
+      else if (this._platform === 'linux')
+        executablePath = path.join(folderPath, 'firefox', 'firefox');
+      else if (this._platform === 'win32' || this._platform === 'win64')
+        executablePath = path.join(folderPath, 'firefox', 'firefox.exe');
+      else
+        throw new Error('Unsupported platform: ' + this._platform);
+    }
+    const url = downloadURL(this._product, this._platform, this._downloadHost, revision);
+    const local = fs.existsSync(folderPath);
+    return {revision, executablePath, folderPath, local, url};
+  }
+
+  _getFolderPath(revision: string): string {
+    return path.join(this._downloadsFolder, this._product + '-' + this._platform + '-' + revision);
+  }
+}
+
+function parseFolderPath(folderPath: string): { platform: string; revision: string; } | null {
+  const name = path.basename(folderPath);
+  const splits = name.split('-');
+  if (splits.length !== 3)
+    return null;
+  const [product, platform, revision] = splits;
+  if (!downloadURLs[product][platform])
+    return null;
+  return {platform, revision};
+}
+
+function downloadFile(url: string, destinationPath: string, progressCallback: ((arg0: number, arg1: number) => void) | null): Promise<any> {
+  let fulfill, reject;
+  let downloadedBytes = 0;
+  let totalBytes = 0;
+
+  const promise = new Promise((x, y) => { fulfill = x; reject = y; });
+
+  const request = httpRequest(url, 'GET', response => {
+    if (response.statusCode !== 200) {
+      const error = new Error(`Download failed: server returned code ${response.statusCode}. URL: ${url}`);
+      // consume response data to free up memory
+      response.resume();
+      reject(error);
+      return;
+    }
+    const file = fs.createWriteStream(destinationPath);
+    file.on('finish', () => fulfill());
+    file.on('error', error => reject(error));
+    response.pipe(file);
+    totalBytes = parseInt(response.headers['content-length'], 10);
+    if (progressCallback)
+      response.on('data', onData);
+  });
+  request.on('error', error => reject(error));
+  return promise;
+
+  function onData(chunk) {
+    downloadedBytes += chunk.length;
+    progressCallback(downloadedBytes, totalBytes);
+  }
+}
+
+function extractZip(zipPath: string, folderPath: string): Promise<Error | null> {
+  return new Promise((fulfill, reject) => extract(zipPath, {dir: folderPath}, err => {
+    if (err)
+      reject(err);
+    else
+      fulfill();
+  }));
+}
+
+function httpRequest(url: string, method: string, onResponse: (response: any) => void) {
+  const options: any = URL.parse(url);
+  options.method = method;
+
+  const proxyURL = getProxyForUrl(url);
+  if (proxyURL) {
+    const parsedProxyURL: any = URL.parse(proxyURL);
+    parsedProxyURL.secureProxy = parsedProxyURL.protocol === 'https:';
+
+    options.agent = new ProxyAgent(parsedProxyURL);
+    options.rejectUnauthorized = false;
+  }
+
+  const requestCallback = res => {
+    if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location)
+      httpRequest(res.headers.location, method, onResponse);
+    else
+      onResponse(res);
+  };
+  const request = options.protocol === 'https:' ?
+    require('https').request(options, requestCallback) :
+    require('http').request(options, requestCallback);
+  request.end();
+  return request;
+}
+
+interface BrowserFetcherOptions {
+  browser?: string;
+  platform?: string;
+  path?: string;
+  host?: string;
+}
+
+interface RevisionInfo {
+  folderPath: string;
+  executablePath: string;
+  url: string;
+  local: boolean;
+  revision: string;
+}
--- a/src/firefox/Connection.ts
+++ b/src/firefox/Connection.ts
@ -0,0 +1,203 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {assert} from '../helper';
+import {EventEmitter} from 'events';
+import * as debug from 'debug';
+import { ConnectionTransport } from '../ConnectionTransport';
+const debugProtocol = debug('playwright:protocol');
+
+export const ConnectionEvents = {
+  Disconnected: Symbol('Disconnected'),
+};
+
+export class Connection extends EventEmitter {
+  private _url: string;
+  private _lastId: number;
+  private _callbacks: Map<number, {resolve: Function, reject: Function, error: Error, method: string}>;
+  private _delay: number;
+  private _transport: ConnectionTransport;
+  private _sessions: Map<string, JugglerSession>;
+  _closed: boolean;
+  constructor(url: string, transport: ConnectionTransport, delay: number | undefined = 0) {
+    super();
+    this._url = url;
+    this._lastId = 0;
+    this._callbacks = new Map();
+    this._delay = delay;
+
+    this._transport = transport;
+    this._transport.onmessage = this._onMessage.bind(this);
+    this._transport.onclose = this._onClose.bind(this);
+    this._sessions = new Map();
+    this._closed = false;
+  }
+
+  static fromSession(session: JugglerSession): Connection {
+    return session._connection;
+  }
+
+  session(sessionId: string): JugglerSession | null {
+    return this._sessions.get(sessionId) || null;
+  }
+
+  url(): string {
+    return this._url;
+  }
+
+  send(method: string, params: object | undefined = {}): Promise<any> {
+    const id = this._rawSend({method, params});
+    return new Promise((resolve, reject) => {
+      this._callbacks.set(id, {resolve, reject, error: new Error(), method});
+    });
+  }
+
+  _rawSend(message: any): number {
+    const id = ++this._lastId;
+    message = JSON.stringify(Object.assign({}, message, {id}));
+    debugProtocol('SEND ► ' + message);
+    this._transport.send(message);
+    return id;
+  }
+
+  async _onMessage(message: string) {
+    if (this._delay)
+      await new Promise(f => setTimeout(f, this._delay));
+    debugProtocol('◀ RECV ' + message);
+    const object = JSON.parse(message);
+    if (object.method === 'Target.attachedToTarget') {
+      const sessionId = object.params.sessionId;
+      const session = new JugglerSession(this, object.params.targetInfo.type, sessionId);
+      this._sessions.set(sessionId, session);
+    } else if (object.method === 'Browser.detachedFromTarget') {
+      const session = this._sessions.get(object.params.sessionId);
+      if (session) {
+        session._onClosed();
+        this._sessions.delete(object.params.sessionId);
+      }
+    }
+    if (object.sessionId) {
+      const session = this._sessions.get(object.sessionId);
+      if (session)
+        session._onMessage(object);
+    } else if (object.id) {
+      const callback = this._callbacks.get(object.id);
+      // Callbacks could be all rejected if someone has called `.dispose()`.
+      if (callback) {
+        this._callbacks.delete(object.id);
+        if (object.error)
+          callback.reject(createProtocolError(callback.error, callback.method, object));
+        else
+          callback.resolve(object.result);
+      }
+    } else {
+      this.emit(object.method, object.params);
+    }
+  }
+
+  _onClose() {
+    if (this._closed)
+      return;
+    this._closed = true;
+    this._transport.onmessage = null;
+    this._transport.onclose = null;
+    for (const callback of this._callbacks.values())
+      callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
+    this._callbacks.clear();
+    for (const session of this._sessions.values())
+      session._onClosed();
+    this._sessions.clear();
+    this.emit(ConnectionEvents.Disconnected);
+  }
+
+  dispose() {
+    this._onClose();
+    this._transport.close();
+  }
+
+  async createSession(targetId: string): Promise<JugglerSession> {
+    const {sessionId} = await this.send('Target.attachToTarget', {targetId});
+    return this._sessions.get(sessionId);
+  }
+}
+
+export const JugglerSessionEvents = {
+  Disconnected: Symbol('Disconnected')
+};
+
+export class JugglerSession extends EventEmitter {
+  _connection: Connection;
+  private _callbacks: Map<number, {resolve: Function, reject: Function, error: Error, method: string}>;
+  private _targetType: string;
+  private _sessionId: string;
+  constructor(connection: Connection, targetType: string, sessionId: string) {
+    super();
+    this._callbacks = new Map();
+    this._connection = connection;
+    this._targetType = targetType;
+    this._sessionId = sessionId;
+  }
+
+  send(method: string, params: any = {}): Promise<any> {
+    if (!this._connection)
+      return Promise.reject(new Error(`Protocol error (${method}): Session closed. Most likely the ${this._targetType} has been closed.`));
+    const id = this._connection._rawSend({sessionId: this._sessionId, method, params});
+    return new Promise((resolve, reject) => {
+      this._callbacks.set(id, {resolve, reject, error: new Error(), method});
+    });
+  }
+
+  _onMessage(object: { id?: number; method: string; params: object; error: { message: string; data: any; }; result?: any; }) {
+    if (object.id && this._callbacks.has(object.id)) {
+      const callback = this._callbacks.get(object.id);
+      this._callbacks.delete(object.id);
+      if (object.error)
+        callback.reject(createProtocolError(callback.error, callback.method, object));
+      else
+        callback.resolve(object.result);
+    } else {
+      assert(!object.id);
+      this.emit(object.method, object.params);
+    }
+  }
+
+  async detach() {
+    if (!this._connection)
+      throw new Error(`Session already detached. Most likely the ${this._targetType} has been closed.`);
+    await this._connection.send('Target.detachFromTarget',  {sessionId: this._sessionId});
+  }
+
+  _onClosed() {
+    for (const callback of this._callbacks.values())
+      callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
+    this._callbacks.clear();
+    this._connection = null;
+    this.emit(JugglerSessionEvents.Disconnected);
+  }
+}
+
+function createProtocolError(error: Error, method: string, object: { error: { message: string; data: any; }; }): Error {
+  let message = `Protocol error (${method}): ${object.error.message}`;
+  if ('data' in object.error)
+    message += ` ${object.error.data}`;
+  return rewriteError(error, message);
+}
+
+function rewriteError(error: Error, message: string): Error {
+  error.message = message;
+  return error;
+}
--- a/src/firefox/DOMWorld.ts
+++ b/src/firefox/DOMWorld.ts
@ -0,0 +1,503 @@
+import {helper, assert} from '../helper';
+import {TimeoutError} from '../Errors';
+import * as fs from 'fs';
+import * as util from 'util';
+import {ElementHandle, JSHandle} from './JSHandle';
+
+const readFileAsync = util.promisify(fs.readFile);
+
+export class DOMWorld {
+  _frame: any;
+  _timeoutSettings: any;
+  _documentPromise: any;
+  _contextPromise: any;
+  _contextResolveCallback: any;
+  _waitTasks: Set<WaitTask>;
+  _detached: boolean;
+  constructor(frame, timeoutSettings) {
+    this._frame = frame;
+    this._timeoutSettings = timeoutSettings;
+
+    this._documentPromise = null;
+    this._contextPromise;
+    this._contextResolveCallback = null;
+    this._setContext(null);
+
+    this._waitTasks = new Set();
+    this._detached = false;
+  }
+
+  frame() {
+    return this._frame;
+  }
+
+  _setContext(context) {
+    if (context) {
+      this._contextResolveCallback.call(null, context);
+      this._contextResolveCallback = null;
+      for (const waitTask of this._waitTasks)
+        waitTask.rerun();
+    } else {
+      this._documentPromise = null;
+      this._contextPromise = new Promise(fulfill => {
+        this._contextResolveCallback = fulfill;
+      });
+    }
+  }
+
+  _detach() {
+    this._detached = true;
+    for (const waitTask of this._waitTasks)
+      waitTask.terminate(new Error('waitForFunction failed: frame got detached.'));
+  }
+
+  async executionContext() {
+    if (this._detached)
+      throw new Error(`Execution Context is not available in detached frame "${this.url()}" (are you trying to evaluate?)`);
+    return this._contextPromise;
+  }
+  url() {
+    throw new Error('Method not implemented.');
+  }
+
+  async evaluateHandle(pageFunction, ...args) {
+    const context = await this.executionContext();
+    return context.evaluateHandle(pageFunction, ...args);
+  }
+
+  async evaluate(pageFunction, ...args) {
+    const context = await this.executionContext();
+    return context.evaluate(pageFunction, ...args);
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    const document = await this._document();
+    return document.$(selector);
+  }
+
+  _document() {
+    if (!this._documentPromise)
+      this._documentPromise = this.evaluateHandle('document').then(handle => handle.asElement());
+    return this._documentPromise;
+  }
+
+  async $x(expression: string): Promise<Array<ElementHandle>> {
+    const document = await this._document();
+    return document.$x(expression);
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    const document = await this._document();
+    return document.$eval(selector, pageFunction, ...args);
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    const document = await this._document();
+    return document.$$eval(selector, pageFunction, ...args);
+  }
+
+  async $$(selector: string): Promise<Array<ElementHandle>> {
+    const document = await this._document();
+    return document.$$(selector);
+  }
+
+  async content(): Promise<string> {
+    return await this.evaluate(() => {
+      let retVal = '';
+      if (document.doctype)
+        retVal = new XMLSerializer().serializeToString(document.doctype);
+      if (document.documentElement)
+        retVal += document.documentElement.outerHTML;
+      return retVal;
+    });
+  }
+
+  async setContent(html: string) {
+    await this.evaluate(html => {
+      document.open();
+      document.write(html);
+      document.close();
+    }, html);
+  }
+
+  async addScriptTag(options: { content?: string; path?: string; type?: string; url?: string; }): Promise<ElementHandle> {
+    if (typeof options.url === 'string') {
+      const url = options.url;
+      try {
+        return (await this.evaluateHandle(addScriptUrl, url, options.type)).asElement();
+      } catch (error) {
+        throw new Error(`Loading script from ${url} failed`);
+      }
+    }
+
+    if (typeof options.path === 'string') {
+      let contents = await readFileAsync(options.path, 'utf8');
+      contents += '//# sourceURL=' + options.path.replace(/\n/g, '');
+      return (await this.evaluateHandle(addScriptContent, contents, options.type)).asElement();
+    }
+
+    if (typeof options.content === 'string')
+      return (await this.evaluateHandle(addScriptContent, options.content, options.type)).asElement();
+
+
+    throw new Error('Provide an object with a `url`, `path` or `content` property');
+
+    async function addScriptUrl(url: string, type: string): Promise<HTMLElement> {
+      const script = document.createElement('script');
+      script.src = url;
+      if (type)
+        script.type = type;
+      const promise = new Promise((res, rej) => {
+        script.onload = res;
+        script.onerror = rej;
+      });
+      document.head.appendChild(script);
+      await promise;
+      return script;
+    }
+
+    function addScriptContent(content: string, type: string = 'text/javascript'): HTMLElement {
+      const script = document.createElement('script');
+      script.type = type;
+      script.text = content;
+      let error = null;
+      script.onerror = e => error = e;
+      document.head.appendChild(script);
+      if (error)
+        throw error;
+      return script;
+    }
+  }
+
+  async addStyleTag(options: { content?: string; path?: string; url?: string; }): Promise<ElementHandle> {
+    if (typeof options.url === 'string') {
+      const url = options.url;
+      try {
+        return (await this.evaluateHandle(addStyleUrl, url)).asElement();
+      } catch (error) {
+        throw new Error(`Loading style from ${url} failed`);
+      }
+    }
+
+    if (typeof options.path === 'string') {
+      let contents = await readFileAsync(options.path, 'utf8');
+      contents += '/*# sourceURL=' + options.path.replace(/\n/g, '') + '*/';
+      return (await this.evaluateHandle(addStyleContent, contents)).asElement();
+    }
+
+    if (typeof options.content === 'string')
+      return (await this.evaluateHandle(addStyleContent, options.content)).asElement();
+
+
+    throw new Error('Provide an object with a `url`, `path` or `content` property');
+
+    async function addStyleUrl(url: string): Promise<HTMLElement> {
+      const link = document.createElement('link');
+      link.rel = 'stylesheet';
+      link.href = url;
+      const promise = new Promise((res, rej) => {
+        link.onload = res;
+        link.onerror = rej;
+      });
+      document.head.appendChild(link);
+      await promise;
+      return link;
+    }
+
+    async function addStyleContent(content: string): Promise<HTMLElement> {
+      const style = document.createElement('style');
+      style.type = 'text/css';
+      style.appendChild(document.createTextNode(content));
+      const promise = new Promise((res, rej) => {
+        style.onload = res;
+        style.onerror = rej;
+      });
+      document.head.appendChild(style);
+      await promise;
+      return style;
+    }
+  }
+
+  async click(selector: string, options: { delay?: number; button?: string; clickCount?: number; } | undefined = {}) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.click(options);
+    await handle.dispose();
+  }
+
+  async focus(selector: string) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.focus();
+    await handle.dispose();
+  }
+
+  async hover(selector: string) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.hover();
+    await handle.dispose();
+  }
+
+  select(selector: string, ...values: Array<string>): Promise<Array<string>> {
+    for (const value of values)
+      assert(helper.isString(value), 'Values must be strings. Found value "' + value + '" of type "' + (typeof value) + '"');
+    return this.$eval(selector, (element : HTMLSelectElement, values : string[]) => {
+      if (element.nodeName.toLowerCase() !== 'select')
+        throw new Error('Element is not a <select> element.');
+
+      const options = Array.from(element.options);
+      element.value = undefined;
+      for (const option of options) {
+        option.selected = values.includes(option.value);
+        if (option.selected && !element.multiple)
+          break;
+      }
+      element.dispatchEvent(new Event('input', { 'bubbles': true }));
+      element.dispatchEvent(new Event('change', { 'bubbles': true }));
+      return options.filter(option => option.selected).map(option => option.value);
+    }, values) as Promise<string[]>;
+  }
+
+  async tap(selector: string) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.tap();
+    await handle.dispose();
+  }
+
+  async type(selector: string, text: string, options: { delay: (number | undefined); } | undefined) {
+    const handle = await this.$(selector);
+    assert(handle, 'No node found for selector: ' + selector);
+    await handle.type(text, options);
+    await handle.dispose();
+  }
+
+  waitForSelector(selector: string, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined): Promise<ElementHandle> {
+    return this._waitForSelectorOrXPath(selector, false, options);
+  }
+
+  waitForXPath(xpath: string, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined): Promise<ElementHandle> {
+    return this._waitForSelectorOrXPath(xpath, true, options);
+  }
+
+  waitForFunction(pageFunction: Function | string, options: { polling?: string | number; timeout?: number; } | undefined = {}, ...args): Promise<JSHandle> {
+    const {
+      polling = 'raf',
+      timeout = this._timeoutSettings.timeout(),
+    } = options;
+    return new WaitTask(this, pageFunction, 'function', polling, timeout, ...args).promise;
+  }
+
+  async title(): Promise<string> {
+    return this.evaluate(() => document.title);
+  }
+
+  async _waitForSelectorOrXPath(selectorOrXPath: string, isXPath: boolean, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined = {}): Promise<ElementHandle> {
+    const {
+      visible: waitForVisible = false,
+      hidden: waitForHidden = false,
+      timeout = this._timeoutSettings.timeout(),
+    } = options;
+    const polling = waitForVisible || waitForHidden ? 'raf' : 'mutation';
+    const title = `${isXPath ? 'XPath' : 'selector'} "${selectorOrXPath}"${waitForHidden ? ' to be hidden' : ''}`;
+    const waitTask = new WaitTask(this, predicate, title, polling, timeout, selectorOrXPath, isXPath, waitForVisible, waitForHidden);
+    const handle = await waitTask.promise;
+    if (!handle.asElement()) {
+      await handle.dispose();
+      return null;
+    }
+    return handle.asElement();
+
+    function predicate(selectorOrXPath: string, isXPath: boolean, waitForVisible: boolean, waitForHidden: boolean): (Node | boolean) | null {
+      const node = isXPath
+        ? document.evaluate(selectorOrXPath, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue
+        : document.querySelector(selectorOrXPath);
+      if (!node)
+        return waitForHidden;
+      if (!waitForVisible && !waitForHidden)
+        return node;
+      const element: Element = node.nodeType === Node.TEXT_NODE ? node.parentElement : node as Element;
+
+      const style = window.getComputedStyle(element);
+      const isVisible = style && style.visibility !== 'hidden' && hasVisibleBoundingBox();
+      const success = (waitForVisible === isVisible || waitForHidden === !isVisible);
+      return success ? node : null;
+
+      function hasVisibleBoundingBox(): boolean {
+        const rect = element.getBoundingClientRect();
+        return !!(rect.top || rect.bottom || rect.width || rect.height);
+      }
+    }
+  }
+}
+
+class WaitTask {
+  promise: any;
+  _domWorld: any;
+  _polling: any;
+  _timeout: any;
+  _predicateBody: string;
+  _args: any[];
+  _runCount: number;
+  _resolve: (value?: unknown) => void;
+  _reject: (reason?: any) => void;
+  _timeoutTimer: NodeJS.Timer;
+  _terminated: boolean;
+  _runningTask: any;
+  constructor(domWorld: DOMWorld, predicateBody: Function | string, title, polling: string | number, timeout: number, ...args: Array<any>) {
+    if (helper.isString(polling))
+      assert(polling === 'raf' || polling === 'mutation', 'Unknown polling option: ' + polling);
+    else if (helper.isNumber(polling))
+      assert(polling > 0, 'Cannot poll with non-positive interval: ' + polling);
+    else
+      throw new Error('Unknown polling options: ' + polling);
+
+    this._domWorld = domWorld;
+    this._polling = polling;
+    this._timeout = timeout;
+    this._predicateBody = helper.isString(predicateBody) ? 'return (' + predicateBody + ')' : 'return (' + predicateBody + ')(...args)';
+    this._args = args;
+    this._runCount = 0;
+    domWorld._waitTasks.add(this);
+    this.promise = new Promise((resolve, reject) => {
+      this._resolve = resolve;
+      this._reject = reject;
+    });
+    // Since page navigation requires us to re-install the pageScript, we should track
+    // timeout on our end.
+    if (timeout) {
+      const timeoutError = new TimeoutError(`waiting for ${title} failed: timeout ${timeout}ms exceeded`);
+      this._timeoutTimer = setTimeout(() => this.terminate(timeoutError), timeout);
+    }
+    this.rerun();
+  }
+
+  terminate(error: Error) {
+    this._terminated = true;
+    this._reject(error);
+    this._cleanup();
+  }
+
+  async rerun() {
+    const runCount = ++this._runCount;
+    let success: JSHandle | null = null;
+    let error = null;
+    try {
+      success = await this._domWorld.evaluateHandle(waitForPredicatePageFunction, this._predicateBody, this._polling, this._timeout, ...this._args);
+    } catch (e) {
+      error = e;
+    }
+
+    if (this._terminated || runCount !== this._runCount) {
+      if (success)
+        await success.dispose();
+      return;
+    }
+
+    // Ignore timeouts in pageScript - we track timeouts ourselves.
+    // If the frame's execution context has already changed, `frame.evaluate` will
+    // throw an error - ignore this predicate run altogether.
+    if (!error && await this._domWorld.evaluate(s => !s, success).catch(e => true)) {
+      await success.dispose();
+      return;
+    }
+
+    // When the page is navigated, the promise is rejected.
+    // Try again right away.
+    if (error && error.message.includes('Execution context was destroyed')) {
+      this.rerun();
+      return;
+    }
+
+    if (error)
+      this._reject(error);
+    else
+      this._resolve(success);
+
+    this._cleanup();
+  }
+
+  _cleanup() {
+    clearTimeout(this._timeoutTimer);
+    this._domWorld._waitTasks.delete(this);
+    this._runningTask = null;
+  }
+}
+
+async function waitForPredicatePageFunction(predicateBody: string, polling: string, timeout: number, ...args): Promise<any> {
+  const predicate = new Function('...args', predicateBody);
+  let timedOut = false;
+  if (timeout)
+    setTimeout(() => timedOut = true, timeout);
+  if (polling === 'raf')
+    return await pollRaf();
+  if (polling === 'mutation')
+    return await pollMutation();
+  if (typeof polling === 'number')
+    return await pollInterval(polling);
+
+  function pollMutation(): Promise<any> {
+    const success = predicate.apply(null, args);
+    if (success)
+      return Promise.resolve(success);
+
+    let fulfill;
+    const result = new Promise(x => fulfill = x);
+    const observer = new MutationObserver(mutations => {
+      if (timedOut) {
+        observer.disconnect();
+        fulfill();
+      }
+      const success = predicate.apply(null, args);
+      if (success) {
+        observer.disconnect();
+        fulfill(success);
+      }
+    });
+    observer.observe(document, {
+      childList: true,
+      subtree: true,
+      attributes: true
+    });
+    return result;
+  }
+
+  function pollRaf(): Promise<any> {
+    let fulfill;
+    const result = new Promise(x => fulfill = x);
+    onRaf();
+    return result;
+
+    function onRaf() {
+      if (timedOut) {
+        fulfill();
+        return;
+      }
+      const success = predicate.apply(null, args);
+      if (success)
+        fulfill(success);
+      else
+        requestAnimationFrame(onRaf);
+    }
+  }
+
+  function pollInterval(pollInterval: number): Promise<any> {
+    let fulfill;
+    const result = new Promise(x => fulfill = x);
+    onTimeout();
+    return result;
+
+    function onTimeout() {
+      if (timedOut) {
+        fulfill();
+        return;
+      }
+      const success = predicate.apply(null, args);
+      if (success)
+        fulfill(success);
+      else
+        setTimeout(onTimeout, pollInterval);
+    }
+  }
+}
--- a/src/firefox/Dialog.ts
+++ b/src/firefox/Dialog.ts
@ -0,0 +1,51 @@
+import {assert, debugError} from '../helper';
+
+export class Dialog {
+  private _client: any;
+  private _dialogId: any;
+  private _type: string;
+  private _message: string;
+  private _handled: boolean;
+  private _defaultValue: string;
+
+  constructor(client, payload) {
+    this._client = client;
+    this._dialogId = payload.dialogId;
+    this._type = payload.type;
+    this._message = payload.message;
+    this._handled = false;
+    this._defaultValue = payload.defaultValue || '';
+  }
+
+  type(): string {
+    return this._type;
+  }
+
+  message(): string {
+    return this._message;
+  }
+
+  defaultValue(): string {
+    return this._defaultValue;
+  }
+
+  async accept(promptText: string | undefined) {
+    assert(!this._handled, 'Cannot accept dialog which is already handled!');
+    this._handled = true;
+    await this._client.send('Page.handleDialog', {
+      dialogId: this._dialogId,
+      accept: true,
+      promptText: promptText
+    }).catch(debugError);
+  }
+
+  async dismiss() {
+    assert(!this._handled, 'Cannot dismiss dialog which is already handled!');
+    this._handled = true;
+    await this._client.send('Page.handleDialog', {
+      dialogId: this._dialogId,
+      accept: false
+    }).catch(debugError);
+  }
+}
+
--- a/src/firefox/ExecutionContext.ts
+++ b/src/firefox/ExecutionContext.ts
@ -0,0 +1,100 @@
+import {helper} from '../helper';
+import {JSHandle, createHandle} from './JSHandle';
+import { Frame } from './FrameManager';
+
+export class ExecutionContext {
+  _session: any;
+  _frame: Frame;
+  _executionContextId: string;
+  constructor(session: any, frame: Frame | null, executionContextId: string) {
+    this._session = session;
+    this._frame = frame;
+    this._executionContextId = executionContextId;
+  }
+
+  async evaluateHandle(pageFunction, ...args) {
+    if (helper.isString(pageFunction)) {
+      const payload = await this._session.send('Runtime.evaluate', {
+        expression: pageFunction,
+        executionContextId: this._executionContextId,
+      }).catch(rewriteError);
+      return createHandle(this, payload.result, payload.exceptionDetails);
+    }
+    if (typeof pageFunction !== 'function')
+      throw new Error(`Expected to get |string| or |function| as the first argument, but got "${pageFunction}" instead.`);
+
+    let functionText = pageFunction.toString();
+    try {
+      new Function('(' + functionText + ')');
+    } catch (e1) {
+      // This means we might have a function shorthand. Try another
+      // time prefixing 'function '.
+      if (functionText.startsWith('async '))
+        functionText = 'async function ' + functionText.substring('async '.length);
+      else
+        functionText = 'function ' + functionText;
+      try {
+        new Function('(' + functionText  + ')');
+      } catch (e2) {
+        // We tried hard to serialize, but there's a weird beast here.
+        throw new Error('Passed function is not well-serializable!');
+      }
+    }
+    args = args.map(arg => {
+      if (arg instanceof JSHandle) {
+        if (arg._context !== this)
+          throw new Error('JSHandles can be evaluated only in the context they were created!');
+        if (arg._disposed)
+          throw new Error('JSHandle is disposed!');
+        return arg._protocolValue;
+      }
+      if (Object.is(arg, Infinity))
+        return {unserializableValue: 'Infinity'};
+      if (Object.is(arg, -Infinity))
+        return {unserializableValue: '-Infinity'};
+      if (Object.is(arg, -0))
+        return {unserializableValue: '-0'};
+      if (Object.is(arg, NaN))
+        return {unserializableValue: 'NaN'};
+      return {value: arg};
+    });
+    let callFunctionPromise;
+    try {
+      callFunctionPromise = this._session.send('Runtime.callFunction', {
+        functionDeclaration: functionText,
+        args,
+        executionContextId: this._executionContextId
+      });
+    } catch (err) {
+      if (err instanceof TypeError && err.message.startsWith('Converting circular structure to JSON'))
+        err.message += ' Are you passing a nested JSHandle?';
+      throw err;
+    }
+    const payload = await callFunctionPromise.catch(rewriteError);
+    return createHandle(this, payload.result, payload.exceptionDetails);
+
+    function rewriteError(error) {
+      if (error.message.includes('Failed to find execution context with id'))
+        throw new Error('Execution context was destroyed, most likely because of a navigation.');
+      throw error;
+    }
+  }
+
+  frame() {
+    return this._frame;
+  }
+
+  async evaluate(pageFunction, ...args) {
+    try {
+      const handle = await this.evaluateHandle(pageFunction, ...args);
+      const result = await handle.jsonValue();
+      await handle.dispose();
+      return result;
+    } catch (e) {
+      if (e.message.includes('cyclic object value') || e.message.includes('Object is not serializable'))
+        return undefined;
+      throw e;
+    }
+  }
+
+}
--- a/src/firefox/FrameManager.ts
+++ b/src/firefox/FrameManager.ts
@ -0,0 +1,394 @@
+import { JugglerSession } from './Connection';
+import { Page } from './Page';
+
+import {RegisteredListener, helper, assert} from '../helper';
+import {TimeoutError} from '../Errors';
+import {EventEmitter} from 'events';
+import {ExecutionContext} from './ExecutionContext';
+import {NavigationWatchdog, NextNavigationWatchdog} from './NavigationWatchdog';
+import {DOMWorld} from './DOMWorld';
+import { JSHandle, ElementHandle } from './JSHandle';
+
+export const FrameManagerEvents = {
+  FrameNavigated: Symbol('FrameManagerEvents.FrameNavigated'),
+  FrameAttached: Symbol('FrameManagerEvents.FrameAttached'),
+  FrameDetached: Symbol('FrameManagerEvents.FrameDetached'),
+  Load: Symbol('FrameManagerEvents.Load'),
+  DOMContentLoaded: Symbol('FrameManagerEvents.DOMContentLoaded'),
+};
+export class FrameManager extends EventEmitter {
+  _session: JugglerSession;
+  _page: Page;
+  _networkManager: any;
+  _timeoutSettings: any;
+  _mainFrame: any;
+  _frames: Map<string, Frame>;
+  _contextIdToContext: Map<string, ExecutionContext>;
+  _eventListeners: RegisteredListener[];
+  constructor(session: JugglerSession, page: Page, networkManager, timeoutSettings) {
+    super();
+    this._session = session;
+    this._page = page;
+    this._networkManager = networkManager;
+    this._timeoutSettings = timeoutSettings;
+    this._mainFrame = null;
+    this._frames = new Map();
+    this._contextIdToContext = new Map();
+    this._eventListeners = [
+      helper.addEventListener(this._session, 'Page.eventFired', this._onEventFired.bind(this)),
+      helper.addEventListener(this._session, 'Page.frameAttached', this._onFrameAttached.bind(this)),
+      helper.addEventListener(this._session, 'Page.frameDetached', this._onFrameDetached.bind(this)),
+      helper.addEventListener(this._session, 'Page.navigationCommitted', this._onNavigationCommitted.bind(this)),
+      helper.addEventListener(this._session, 'Page.sameDocumentNavigation', this._onSameDocumentNavigation.bind(this)),
+      helper.addEventListener(this._session, 'Runtime.executionContextCreated', this._onExecutionContextCreated.bind(this)),
+      helper.addEventListener(this._session, 'Runtime.executionContextDestroyed', this._onExecutionContextDestroyed.bind(this)),
+    ];
+  }
+
+  executionContextById(executionContextId) {
+    return this._contextIdToContext.get(executionContextId) || null;
+  }
+
+  _onExecutionContextCreated({executionContextId, auxData}) {
+    const frameId = auxData ? auxData.frameId : null;
+    const frame = this._frames.get(frameId) || null;
+    const context = new ExecutionContext(this._session, frame, executionContextId);
+    if (frame)
+      frame._mainWorld._setContext(context);
+    this._contextIdToContext.set(executionContextId, context);
+  }
+
+  _onExecutionContextDestroyed({executionContextId}) {
+    const context = this._contextIdToContext.get(executionContextId);
+    if (!context)
+      return;
+    this._contextIdToContext.delete(executionContextId);
+    if (context._frame)
+      context._frame._mainWorld._setContext(null);
+  }
+
+  frame(frameId) {
+    return this._frames.get(frameId);
+  }
+
+  mainFrame() {
+    return this._mainFrame;
+  }
+
+  frames() {
+    const frames: Array<Frame> = [];
+    collect(this._mainFrame);
+    return frames;
+
+    function collect(frame) {
+      frames.push(frame);
+      for (const subframe of frame._children)
+        collect(subframe);
+    }
+  }
+
+  _onNavigationCommitted(params) {
+    const frame = this._frames.get(params.frameId);
+    frame._navigated(params.url, params.name, params.navigationId);
+    this.emit(FrameManagerEvents.FrameNavigated, frame);
+  }
+
+  _onSameDocumentNavigation(params) {
+    const frame = this._frames.get(params.frameId);
+    frame._url = params.url;
+    this.emit(FrameManagerEvents.FrameNavigated, frame);
+  }
+
+  _onFrameAttached(params) {
+    const frame = new Frame(this._session, this, this._networkManager, this._page, params.frameId, this._timeoutSettings);
+    const parentFrame = this._frames.get(params.parentFrameId) || null;
+    if (parentFrame) {
+      frame._parentFrame = parentFrame;
+      parentFrame._children.add(frame);
+    } else {
+      assert(!this._mainFrame, 'INTERNAL ERROR: re-attaching main frame!');
+      this._mainFrame = frame;
+    }
+    this._frames.set(params.frameId, frame);
+    this.emit(FrameManagerEvents.FrameAttached, frame);
+  }
+
+  _onFrameDetached(params) {
+    const frame = this._frames.get(params.frameId);
+    this._frames.delete(params.frameId);
+    frame._detach();
+    this.emit(FrameManagerEvents.FrameDetached, frame);
+  }
+
+  _onEventFired({frameId, name}) {
+    const frame = this._frames.get(frameId);
+    frame._firedEvents.add(name.toLowerCase());
+    if (frame === this._mainFrame) {
+      if (name === 'load')
+        this.emit(FrameManagerEvents.Load);
+      else if (name === 'DOMContentLoaded')
+        this.emit(FrameManagerEvents.DOMContentLoaded);
+    }
+  }
+
+  dispose() {
+    helper.removeEventListeners(this._eventListeners);
+  }
+}
+
+export class Frame {
+  _parentFrame: Frame|null = null;
+  private _session: JugglerSession;
+  _page: any;
+  _frameManager: FrameManager;
+  private _networkManager: any;
+  private _timeoutSettings: any;
+  _frameId: string;
+  _url: string = '';
+  private _name: string = '';
+  _children: Set<Frame>;
+  private _detached: boolean;
+  _firedEvents: Set<string>;
+  _mainWorld: any;
+  _lastCommittedNavigationId: any;
+  constructor(session: JugglerSession, frameManager : FrameManager, networkManager, page: Page, frameId: string, timeoutSettings) {
+    this._session = session;
+    this._page = page;
+    this._frameManager = frameManager;
+    this._networkManager = networkManager;
+    this._timeoutSettings = timeoutSettings;
+    this._frameId = frameId;
+    this._children = new Set();
+    this._detached = false;
+
+
+    this._firedEvents = new Set();
+
+    this._mainWorld = new DOMWorld(this, timeoutSettings);
+  }
+
+  async executionContext() {
+    return this._mainWorld.executionContext();
+  }
+
+  async waitForNavigation(options: { timeout?: number; waitUntil?: string | Array<string>; } = {}) {
+    const {
+      timeout = this._timeoutSettings.navigationTimeout(),
+      waitUntil = ['load'],
+    } = options;
+    const normalizedWaitUntil = normalizeWaitUntil(waitUntil);
+
+    const timeoutError = new TimeoutError('Navigation timeout of ' + timeout + ' ms exceeded');
+    let timeoutCallback;
+    const timeoutPromise = new Promise(resolve => timeoutCallback = resolve.bind(null, timeoutError));
+    const timeoutId = timeout ? setTimeout(timeoutCallback, timeout) : null;
+
+    const nextNavigationDog = new NextNavigationWatchdog(this._session, this);
+    const error1 = await Promise.race([
+      nextNavigationDog.promise(),
+      timeoutPromise,
+    ]);
+    nextNavigationDog.dispose();
+
+    // If timeout happened first - throw.
+    if (error1) {
+      clearTimeout(timeoutId);
+      throw error1;
+    }
+
+    const {navigationId, url} = nextNavigationDog.navigation();
+
+    if (!navigationId) {
+      // Same document navigation happened.
+      clearTimeout(timeoutId);
+      return null;
+    }
+
+    const watchDog = new NavigationWatchdog(this._session, this, this._networkManager, navigationId, url, normalizedWaitUntil);
+    const error = await Promise.race([
+      timeoutPromise,
+      watchDog.promise(),
+    ]);
+    watchDog.dispose();
+    clearTimeout(timeoutId);
+    if (error)
+      throw error;
+    return watchDog.navigationResponse();
+  }
+
+  async goto(url: string, options: { timeout?: number; waitUntil?: string | Array<string>; referer?: string; } = {}) {
+    const {
+      timeout = this._timeoutSettings.navigationTimeout(),
+      waitUntil = ['load'],
+      referer,
+    } = options;
+    const normalizedWaitUntil = normalizeWaitUntil(waitUntil);
+    const {navigationId} = await this._session.send('Page.navigate', {
+      frameId: this._frameId,
+      referer,
+      url,
+    });
+    if (!navigationId)
+      return;
+
+    const timeoutError = new TimeoutError('Navigation timeout of ' + timeout + ' ms exceeded');
+    let timeoutCallback;
+    const timeoutPromise = new Promise(resolve => timeoutCallback = resolve.bind(null, timeoutError));
+    const timeoutId = timeout ? setTimeout(timeoutCallback, timeout) : null;
+
+    const watchDog = new NavigationWatchdog(this._session, this, this._networkManager, navigationId, url, normalizedWaitUntil);
+    const error = await Promise.race([
+      timeoutPromise,
+      watchDog.promise(),
+    ]);
+    watchDog.dispose();
+    clearTimeout(timeoutId);
+    if (error)
+      throw error;
+    return watchDog.navigationResponse();
+  }
+
+  async click(selector: string, options: { delay?: number; button?: string; clickCount?: number; } | undefined = {}) {
+    return this._mainWorld.click(selector, options);
+  }
+
+  async tap(selector: string) {
+    return this._mainWorld.tap(selector);
+  }
+
+  async type(selector: string, text: string, options: { delay: (number | undefined); } | undefined) {
+    return this._mainWorld.type(selector, text, options);
+  }
+
+  async focus(selector: string) {
+    return this._mainWorld.focus(selector);
+  }
+
+  async hover(selector: string) {
+    return this._mainWorld.hover(selector);
+  }
+
+  _detach() {
+    this._parentFrame._children.delete(this);
+    this._parentFrame = null;
+    this._detached = true;
+    this._mainWorld._detach();
+  }
+
+  _navigated(url, name, navigationId) {
+    this._url = url;
+    this._name = name;
+    this._lastCommittedNavigationId = navigationId;
+    this._firedEvents.clear();
+  }
+
+  select(selector: string, ...values: Array<string>): Promise<Array<string>> {
+    return this._mainWorld.select(selector, ...values);
+  }
+
+  waitFor(selectorOrFunctionOrTimeout: (string | number | Function), options: { polling?: string | number; timeout?: number; visible?: boolean; hidden?: boolean; } | undefined, ...args: Array<any>): Promise<JSHandle> {
+    const xPathPattern = '//';
+
+    if (helper.isString(selectorOrFunctionOrTimeout)) {
+      const string = selectorOrFunctionOrTimeout;
+      if (string.startsWith(xPathPattern))
+        return this.waitForXPath(string, options);
+      return this.waitForSelector(string, options);
+    }
+    if (helper.isNumber(selectorOrFunctionOrTimeout))
+      return new Promise(fulfill => setTimeout(fulfill, selectorOrFunctionOrTimeout));
+    if (typeof selectorOrFunctionOrTimeout === 'function')
+      return this.waitForFunction(selectorOrFunctionOrTimeout, options, ...args);
+    return Promise.reject(new Error('Unsupported target type: ' + (typeof selectorOrFunctionOrTimeout)));
+  }
+
+  waitForFunction(pageFunction: Function | string, options: { polling?: string | number; timeout?: number; } | undefined = {}, ...args): Promise<JSHandle> {
+    return this._mainWorld.waitForFunction(pageFunction, options, ...args);
+  }
+
+  waitForSelector(selector: string, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined): Promise<ElementHandle> {
+    return this._mainWorld.waitForSelector(selector, options);
+  }
+
+  waitForXPath(xpath: string, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined): Promise<ElementHandle> {
+    return this._mainWorld.waitForXPath(xpath, options);
+  }
+
+  async content(): Promise<string> {
+    return this._mainWorld.content();
+  }
+
+  async setContent(html: string) {
+    return this._mainWorld.setContent(html);
+  }
+
+  async evaluate(pageFunction, ...args) {
+    return this._mainWorld.evaluate(pageFunction, ...args);
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    return this._mainWorld.$(selector);
+  }
+
+  async $$(selector: string): Promise<Array<ElementHandle>> {
+    return this._mainWorld.$$(selector);
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    return this._mainWorld.$eval(selector, pageFunction, ...args);
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    return this._mainWorld.$$eval(selector, pageFunction, ...args);
+  }
+
+  async $x(expression: string): Promise<Array<ElementHandle>> {
+    return this._mainWorld.$x(expression);
+  }
+
+  async evaluateHandle(pageFunction, ...args) {
+    return this._mainWorld.evaluateHandle(pageFunction, ...args);
+  }
+
+  async addScriptTag(options: { content?: string; path?: string; type?: string; url?: string; }): Promise<ElementHandle> {
+    return this._mainWorld.addScriptTag(options);
+  }
+
+  async addStyleTag(options: { content?: string; path?: string; url?: string; }): Promise<ElementHandle> {
+    return this._mainWorld.addStyleTag(options);
+  }
+
+  async title(): Promise<string> {
+    return this._mainWorld.title();
+  }
+
+  name() {
+    return this._name;
+  }
+
+  isDetached() {
+    return this._detached;
+  }
+
+  childFrames() {
+    return Array.from(this._children);
+  }
+
+  url() {
+    return this._url;
+  }
+
+  parentFrame() {
+    return this._parentFrame;
+  }
+}
+
+export function normalizeWaitUntil(waitUntil) {
+  if (!Array.isArray(waitUntil))
+    waitUntil = [waitUntil];
+  for (const condition of waitUntil) {
+    if (condition !== 'load' && condition !== 'domcontentloaded')
+      throw new Error('Unknown waitUntil condition: ' + condition);
+  }
+  return waitUntil;
+}
--- a/src/firefox/Input.ts
+++ b/src/firefox/Input.ts
@ -0,0 +1,292 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { keyDefinitions } from '../USKeyboardLayout';
+import { JugglerSession } from './Connection';
+
+interface KeyDescription {
+  keyCode: number;
+  key: string;
+  text: string;
+  code: string;
+  location: number;
+}
+
+export class Keyboard {
+  _client: JugglerSession;
+  _modifiers: number;
+  _pressedKeys: Set<string>;
+  constructor(client: JugglerSession) {
+    this._client = client;
+    this._modifiers = 0;
+    this._pressedKeys = new Set();
+  }
+
+  async down(key: string) {
+    const description = this._keyDescriptionForString(key);
+
+    const repeat = this._pressedKeys.has(description.code);
+    this._pressedKeys.add(description.code);
+    this._modifiers |= this._modifierBit(description.key);
+
+    await this._client.send('Page.dispatchKeyEvent', {
+      type: 'keydown',
+      keyCode: description.keyCode,
+      code: description.code,
+      key: description.key,
+      repeat,
+      location: description.location
+    });
+  }
+
+  _modifierBit(key: string): number {
+    if (key === 'Alt')
+      return 1;
+    if (key === 'Control')
+      return 2;
+    if (key === 'Shift')
+      return 4;
+    if (key === 'Meta')
+      return 8;
+    return 0;
+  }
+
+  _keyDescriptionForString(keyString: string): KeyDescription {
+    const shift = this._modifiers & 8;
+    const description = {
+      key: '',
+      keyCode: 0,
+      code: '',
+      text: '',
+      location: 0
+    };
+    const definition = keyDefinitions[keyString];
+    if (!definition)
+      throw new Error(`Unknown key: "${keyString}"`);
+
+    if (definition.key)
+      description.key = definition.key;
+    if (shift && definition.shiftKey)
+      description.key = definition.shiftKey;
+
+    if (definition.keyCode)
+      description.keyCode = definition.keyCode;
+    if (shift && definition.shiftKeyCode)
+      description.keyCode = definition.shiftKeyCode;
+
+    if (definition.code)
+      description.code = definition.code;
+
+    if (definition.location)
+      description.location = definition.location;
+
+    if (description.key.length === 1)
+      description.text = description.key;
+
+    if (definition.text)
+      description.text = definition.text;
+    if (shift && definition.shiftText)
+      description.text = definition.shiftText;
+
+    // if any modifiers besides shift are pressed, no text should be sent
+    if (this._modifiers & ~8)
+      description.text = '';
+
+    if (description.code === 'MetaLeft')
+      description.code = 'OSLeft';
+    if (description.code === 'MetaRight')
+      description.code = 'OSRight';
+    return description;
+  }
+
+  async up(key: string) {
+    const description = this._keyDescriptionForString(key);
+
+    this._modifiers &= ~this._modifierBit(description.key);
+    this._pressedKeys.delete(description.code);
+    await this._client.send('Page.dispatchKeyEvent', {
+      type: 'keyup',
+      key: description.key,
+      keyCode: description.keyCode,
+      code: description.code,
+      location: description.location,
+      repeat: false
+    });
+  }
+
+  async sendCharacter(char: string) {
+    await this._client.send('Page.insertText', {
+      text: char
+    });
+  }
+
+  async type(text: string, options: { delay?: number; } | undefined = {}) {
+    const {delay = null} = options;
+    for (const char of text) {
+      if (keyDefinitions[char])
+        await this.press(char, {delay});
+      else
+        await this.sendCharacter(char);
+      if (delay !== null)
+        await new Promise(f => setTimeout(f, delay));
+    }
+  }
+
+  async press(key: string, options: { delay?: number; } | undefined = {}) {
+    const {delay = null} = options;
+    await this.down(key);
+    if (delay !== null)
+      await new Promise(f => setTimeout(f, options.delay));
+    await this.up(key);
+  }
+}
+
+export class Mouse {
+  _client: any;
+  _keyboard: Keyboard;
+  _x: number;
+  _y: number;
+  _buttons: number;
+  constructor(client, keyboard: Keyboard) {
+    this._client = client;
+    this._keyboard = keyboard;
+    this._x = 0;
+    this._y = 0;
+    this._buttons = 0;
+  }
+
+  async move(x: number, y: number, options: { steps?: number; } | undefined = {}) {
+    const {steps = 1} = options;
+    const fromX = this._x, fromY = this._y;
+    this._x = x;
+    this._y = y;
+    for (let i = 1; i <= steps; i++) {
+      await this._client.send('Page.dispatchMouseEvent', {
+        type: 'mousemove',
+        button: 0,
+        x: fromX + (this._x - fromX) * (i / steps),
+        y: fromY + (this._y - fromY) * (i / steps),
+        modifiers: this._keyboard._modifiers,
+        buttons: this._buttons,
+      });
+    }
+  }
+
+  async click(x: number, y: number, options: { delay?: number; button?: string; clickCount?: number; } | undefined = {}) {
+    const {delay = null} = options;
+    if (delay !== null) {
+      await Promise.all([
+        this.move(x, y),
+        this.down(options),
+      ]);
+      await new Promise(f => setTimeout(f, delay));
+      await this.up(options);
+    } else {
+      await Promise.all([
+        this.move(x, y),
+        this.down(options),
+        this.up(options),
+      ]);
+    }
+  }
+
+  async down(options: { button?: string; clickCount?: number; } | undefined = {}) {
+    const {
+      button = 'left',
+      clickCount = 1
+    } = options;
+    if (button === 'left')
+      this._buttons |= 1;
+    if (button === 'right')
+      this._buttons |= 2;
+    if (button === 'middle')
+      this._buttons |= 4;
+    await this._client.send('Page.dispatchMouseEvent', {
+      type: 'mousedown',
+      button: this._buttonNameToButton(button),
+      x: this._x,
+      y: this._y,
+      modifiers: this._keyboard._modifiers,
+      clickCount,
+      buttons: this._buttons,
+    });
+  }
+
+  _buttonNameToButton(buttonName: string): number {
+    if (buttonName === 'left')
+      return 0;
+    if (buttonName === 'middle')
+      return 1;
+    if (buttonName === 'right')
+      return 2;
+  }
+
+  async up(options: { button?: string; clickCount?: number; } | undefined = {}) {
+    const {
+      button = 'left',
+      clickCount = 1
+    } = options;
+    if (button === 'left')
+      this._buttons &= ~1;
+    if (button === 'right')
+      this._buttons &= ~2;
+    if (button === 'middle')
+      this._buttons &= ~4;
+    await this._client.send('Page.dispatchMouseEvent', {
+      type: 'mouseup',
+      button: this._buttonNameToButton(button),
+      x: this._x,
+      y: this._y,
+      modifiers: this._keyboard._modifiers,
+      clickCount: clickCount,
+      buttons: this._buttons,
+    });
+  }
+}
+
+export class Touchscreen {
+  _client: JugglerSession;
+  _keyboard: Keyboard;
+  _mouse: Mouse;
+  constructor(client: JugglerSession, keyboard: Keyboard, mouse: Mouse) {
+    this._client = client;
+    this._keyboard = keyboard;
+    this._mouse = mouse;
+  }
+
+  async tap(x: number, y: number) {
+    const touchPoints = [{x: Math.round(x), y: Math.round(y)}];
+    let {defaultPrevented} = (await this._client.send('Page.dispatchTouchEvent', {
+      type: 'touchStart',
+      touchPoints,
+      modifiers: this._keyboard._modifiers
+    }));
+    defaultPrevented = (await this._client.send('Page.dispatchTouchEvent', {
+      type: 'touchEnd',
+      touchPoints,
+      modifiers: this._keyboard._modifiers
+    })).defaultPrevented || defaultPrevented;
+    // Do not dispatch related mouse events if either of touch events
+    // were prevented.
+    // See https://developer.mozilla.org/en-US/docs/Web/API/Touch_events/Supporting_both_TouchEvent_and_MouseEvent#Event_order
+    if (defaultPrevented)
+      return;
+    await this._mouse.move(x, y);
+    await this._mouse.down();
+    await this._mouse.up();
+  }
+}
--- a/src/firefox/JSHandle.ts
+++ b/src/firefox/JSHandle.ts
@ -0,0 +1,360 @@
+import {assert, debugError} from '../helper';
+import * as path from 'path';
+import {ExecutionContext} from './ExecutionContext';
+import {Frame} from './FrameManager';
+
+export class JSHandle {
+  _context: ExecutionContext;
+  _session: any;
+  _executionContextId: any;
+  _objectId: any;
+  _type: any;
+  _subtype: any;
+  _disposed: boolean;
+  _protocolValue: { unserializableValue: any; value: any; objectId: any; };
+  constructor(context: ExecutionContext, payload: any) {
+    this._context = context;
+    this._session = this._context._session;
+    this._executionContextId = this._context._executionContextId;
+    this._objectId = payload.objectId;
+    this._type = payload.type;
+    this._subtype = payload.subtype;
+    this._disposed = false;
+    this._protocolValue = {
+      unserializableValue: payload.unserializableValue,
+      value: payload.value,
+      objectId: payload.objectId,
+    };
+  }
+
+  executionContext(): ExecutionContext {
+    return this._context;
+  }
+
+  toString(): string {
+    if (this._objectId)
+      return 'JSHandle@' + (this._subtype || this._type);
+    return 'JSHandle:' + this._deserializeValue(this._protocolValue);
+  }
+
+  async getProperty(propertyName: string): Promise<JSHandle | null> {
+    const objectHandle = await this._context.evaluateHandle((object, propertyName) => {
+      const result = {__proto__: null};
+      result[propertyName] = object[propertyName];
+      return result;
+    }, this, propertyName);
+    const properties = await objectHandle.getProperties();
+    const result = properties.get(propertyName) || null;
+    await objectHandle.dispose();
+    return result;
+  }
+
+  async getProperties(): Promise<Map<string, JSHandle>> {
+    const response = await this._session.send('Runtime.getObjectProperties', {
+      executionContextId: this._executionContextId,
+      objectId: this._objectId,
+    });
+    const result = new Map();
+    for (const property of response.properties)
+      result.set(property.name, createHandle(this._context, property.value, null));
+
+    return result;
+  }
+
+  _deserializeValue({unserializableValue, value}) {
+    if (unserializableValue === 'Infinity')
+      return Infinity;
+    if (unserializableValue === '-Infinity')
+      return -Infinity;
+    if (unserializableValue === '-0')
+      return -0;
+    if (unserializableValue === 'NaN')
+      return NaN;
+    return value;
+  }
+
+  async jsonValue() {
+    if (!this._objectId)
+      return this._deserializeValue(this._protocolValue);
+    const simpleValue = await this._session.send('Runtime.callFunction', {
+      executionContextId: this._executionContextId,
+      returnByValue: true,
+      functionDeclaration: (e => e).toString(),
+      args: [this._protocolValue],
+    });
+    return this._deserializeValue(simpleValue.result);
+  }
+
+  asElement(): ElementHandle | null {
+    return null;
+  }
+
+  async dispose() {
+    if (!this._objectId)
+      return;
+    this._disposed = true;
+    await this._session.send('Runtime.disposeObject', {
+      executionContextId: this._executionContextId,
+      objectId: this._objectId,
+    }).catch(error => {
+      // Exceptions might happen in case of a page been navigated or closed.
+      // Swallow these since they are harmless and we don't leak anything in this case.
+      debugError(error);
+    });
+  }
+}
+
+export class ElementHandle extends JSHandle {
+  _frame: Frame;
+  _frameId: any;
+  constructor(frame: Frame, context: ExecutionContext, payload: any) {
+    super(context, payload);
+    this._frame = frame;
+    this._frameId = frame._frameId;
+  }
+
+  async contentFrame(): Promise<Frame | null> {
+    const {frameId} = await this._session.send('Page.contentFrame', {
+      frameId: this._frameId,
+      objectId: this._objectId,
+    });
+    if (!frameId)
+      return null;
+    const frame = this._frame._frameManager.frame(frameId);
+    return frame;
+  }
+
+  asElement(): ElementHandle {
+    return this;
+  }
+
+  async boundingBox(): Promise<{ width: number; height: number; x: number; y: number; }> {
+    return await this._session.send('Page.getBoundingBox', {
+      frameId: this._frameId,
+      objectId: this._objectId,
+    });
+  }
+
+  async screenshot(options: { encoding?: string; path?: string; } = {}) {
+    const clip = await this._session.send('Page.getBoundingBox', {
+      frameId: this._frameId,
+      objectId: this._objectId,
+    });
+    if (!clip)
+      throw new Error('Node is either not visible or not an HTMLElement');
+    assert(clip.width, 'Node has 0 width.');
+    assert(clip.height, 'Node has 0 height.');
+    await this._scrollIntoViewIfNeeded();
+
+    return await this._frame._page.screenshot(Object.assign({}, options, {
+      clip: {
+        x: clip.x,
+        y: clip.y,
+        width: clip.width,
+        height: clip.height,
+      },
+    }));
+  }
+
+  isIntersectingViewport(): Promise<boolean> {
+    return this._frame.evaluate(async element => {
+      const visibleRatio = await new Promise(resolve => {
+        const observer = new IntersectionObserver(entries => {
+          resolve(entries[0].intersectionRatio);
+          observer.disconnect();
+        });
+        observer.observe(element);
+        // Firefox doesn't call IntersectionObserver callback unless
+        // there are rafs.
+        requestAnimationFrame(() => {});
+      });
+      return visibleRatio > 0;
+    }, this);
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    const handle = await this._frame.evaluateHandle(
+        (element, selector) => element.querySelector(selector),
+        this, selector
+    );
+    const element = handle.asElement();
+    if (element)
+      return element;
+    await handle.dispose();
+    return null;
+  }
+
+  async $$(selector: string): Promise<Array<ElementHandle>> {
+    const arrayHandle = await this._frame.evaluateHandle(
+        (element, selector) => element.querySelectorAll(selector),
+        this, selector
+    );
+    const properties = await arrayHandle.getProperties();
+    await arrayHandle.dispose();
+    const result = [];
+    for (const property of properties.values()) {
+      const elementHandle = property.asElement();
+      if (elementHandle)
+        result.push(elementHandle);
+    }
+    return result;
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    const elementHandle = await this.$(selector);
+    if (!elementHandle)
+      throw new Error(`Error: failed to find element matching selector "${selector}"`);
+    const result = await this._frame.evaluate(pageFunction, elementHandle, ...args);
+    await elementHandle.dispose();
+    return result;
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    const arrayHandle = await this._frame.evaluateHandle(
+        (element, selector) => Array.from(element.querySelectorAll(selector)),
+        this, selector
+    );
+
+    const result = await this._frame.evaluate(pageFunction, arrayHandle, ...args);
+    await arrayHandle.dispose();
+    return result;
+  }
+
+  async $x(expression: string): Promise<Array<ElementHandle>> {
+    const arrayHandle = await this._frame.evaluateHandle(
+        (element, expression) => {
+          const document = element.ownerDocument || element;
+          const iterator = document.evaluate(expression, element, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE);
+          const array = [];
+          let item;
+          while ((item = iterator.iterateNext()))
+            array.push(item);
+          return array;
+        },
+        this, expression
+    );
+    const properties = await arrayHandle.getProperties();
+    await arrayHandle.dispose();
+    const result = [];
+    for (const property of properties.values()) {
+      const elementHandle = property.asElement();
+      if (elementHandle)
+        result.push(elementHandle);
+    }
+    return result;
+  }
+
+  async _scrollIntoViewIfNeeded() {
+    const error = await this._frame.evaluate(async element => {
+      if (!element.isConnected)
+        return 'Node is detached from document';
+      if (element.nodeType !== Node.ELEMENT_NODE)
+        return 'Node is not of type HTMLElement';
+      const visibleRatio = await new Promise(resolve => {
+        const observer = new IntersectionObserver(entries => {
+          resolve(entries[0].intersectionRatio);
+          observer.disconnect();
+        });
+        observer.observe(element);
+        // Firefox doesn't call IntersectionObserver callback unless
+        // there are rafs.
+        requestAnimationFrame(() => {});
+      });
+      if (visibleRatio !== 1.0)
+        element.scrollIntoView({block: 'center', inline: 'center', behavior: 'instant'});
+      return false;
+    }, this);
+    if (error)
+      throw new Error(error);
+  }
+
+  async click(options: { delay?: number; button?: string; clickCount?: number; } | undefined) {
+    await this._scrollIntoViewIfNeeded();
+    const {x, y} = await this._clickablePoint();
+    await this._frame._page.mouse.click(x, y, options);
+  }
+
+  async tap() {
+    await this._scrollIntoViewIfNeeded();
+    const {x, y} = await this._clickablePoint();
+    await this._frame._page.touchscreen.tap(x, y);
+  }
+
+  async uploadFile(...filePaths: Array<string>) {
+    const files = filePaths.map(filePath => path.resolve(filePath));
+    await this._session.send('Page.setFileInputFiles', {
+      frameId: this._frameId,
+      objectId: this._objectId,
+      files,
+    });
+  }
+
+  async hover() {
+    await this._scrollIntoViewIfNeeded();
+    const {x, y} = await this._clickablePoint();
+    await this._frame._page.mouse.move(x, y);
+  }
+
+  async focus() {
+    await this._frame.evaluate(element => element.focus(), this);
+  }
+
+  async type(text: string, options: { delay: (number | undefined); } | undefined) {
+    await this.focus();
+    await this._frame._page.keyboard.type(text, options);
+  }
+
+  async press(key: string, options: { delay?: number; } | undefined) {
+    await this.focus();
+    await this._frame._page.keyboard.press(key, options);
+  }
+
+
+  async _clickablePoint(): Promise<{ x: number; y: number; }> {
+    const result = await this._session.send('Page.getContentQuads', {
+      frameId: this._frameId,
+      objectId: this._objectId,
+    }).catch(debugError);
+    if (!result || !result.quads.length)
+      throw new Error('Node is either not visible or not an HTMLElement');
+    // Filter out quads that have too small area to click into.
+    const quads = result.quads.filter(quad => computeQuadArea(quad) > 1);
+    if (!quads.length)
+      throw new Error('Node is either not visible or not an HTMLElement');
+    // Return the middle point of the first quad.
+    return computeQuadCenter(quads[0]);
+  }
+}
+
+export function createHandle(context: ExecutionContext, result: any, exceptionDetails?: any) {
+  const frame = context.frame();
+  if (exceptionDetails) {
+    if (exceptionDetails.value)
+      throw new Error('Evaluation failed: ' + JSON.stringify(exceptionDetails.value));
+    else
+      throw new Error('Evaluation failed: ' + exceptionDetails.text + '\n' + exceptionDetails.stack);
+  }
+  return result.subtype === 'node' ? new ElementHandle(frame, context, result) : new JSHandle(context, result);
+}
+
+function computeQuadArea(quad) {
+  // Compute sum of all directed areas of adjacent triangles
+  // https://en.wikipedia.org/wiki/Polygon#Simple_polygons
+  let area = 0;
+  const points = [quad.p1, quad.p2, quad.p3, quad.p4];
+  for (let i = 0; i < points.length; ++i) {
+    const p1 = points[i];
+    const p2 = points[(i + 1) % points.length];
+    area += (p1.x * p2.y - p2.x * p1.y) / 2;
+  }
+  return Math.abs(area);
+}
+
+function computeQuadCenter(quad) {
+  let x = 0, y = 0;
+  for (const point of [quad.p1, quad.p2, quad.p3, quad.p4]) {
+    x += point.x;
+    y += point.y;
+  }
+  return {x: x / 4, y: y / 4};
+}
--- a/src/firefox/Launcher.ts
+++ b/src/firefox/Launcher.ts
@ -0,0 +1,268 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import * as os from 'os';
+import * as path from 'path';
+import * as removeFolder from 'rimraf';
+import * as childProcess from 'child_process';
+import {Connection} from './Connection';
+import {Browser} from './Browser';
+import {BrowserFetcher} from './BrowserFetcher';
+import * as readline from 'readline';
+import * as fs from 'fs';
+import * as util from 'util';
+import {helper, debugError} from '../helper';
+import {TimeoutError} from '../Errors';
+import {WebSocketTransport} from './WebSocketTransport';
+
+const mkdtempAsync = util.promisify(fs.mkdtemp);
+const removeFolderAsync = util.promisify(removeFolder);
+
+const FIREFOX_PROFILE_PATH = path.join(os.tmpdir(), 'playwright_firefox_profile-');
+
+const DEFAULT_ARGS = [
+  '-no-remote',
+  '-foreground',
+];
+
+export class Launcher {
+  private _projectRoot: string;
+  private _preferredRevision: string;
+  constructor(projectRoot, preferredRevision) {
+    this._projectRoot = projectRoot;
+    this._preferredRevision = preferredRevision;
+  }
+
+  defaultArgs(options: any = {}) {
+    const {
+      headless = true,
+      args = [],
+      userDataDir = null,
+    } = options;
+    const firefoxArguments = [...DEFAULT_ARGS];
+    if (userDataDir)
+      firefoxArguments.push('-profile', userDataDir);
+    if (headless)
+      firefoxArguments.push('-headless');
+    firefoxArguments.push(...args);
+    if (args.every(arg => arg.startsWith('-')))
+      firefoxArguments.push('about:blank');
+    return firefoxArguments;
+  }
+
+  async launch(options: any = {}): Promise<Browser> {
+    const {
+      ignoreDefaultArgs = false,
+      args = [],
+      dumpio = false,
+      executablePath = null,
+      env = process.env,
+      handleSIGHUP = true,
+      handleSIGINT = true,
+      handleSIGTERM = true,
+      ignoreHTTPSErrors = false,
+      defaultViewport = {width: 800, height: 600},
+      slowMo = 0,
+      timeout = 30000,
+    } = options;
+
+    const firefoxArguments = [];
+    if (!ignoreDefaultArgs)
+      firefoxArguments.push(...this.defaultArgs(options));
+    else if (Array.isArray(ignoreDefaultArgs))
+      firefoxArguments.push(...this.defaultArgs(options).filter(arg => !ignoreDefaultArgs.includes(arg)));
+    else
+      firefoxArguments.push(...args);
+
+    if (!firefoxArguments.includes('-juggler'))
+      firefoxArguments.push('-juggler', '0');
+
+    let temporaryProfileDir = null;
+    if (!firefoxArguments.includes('-profile') && !firefoxArguments.includes('--profile')) {
+      temporaryProfileDir = await mkdtempAsync(FIREFOX_PROFILE_PATH);
+      firefoxArguments.push(`-profile`, temporaryProfileDir);
+    }
+
+    let firefoxExecutable = executablePath;
+    if (!firefoxExecutable) {
+      const {missingText, executablePath} = this._resolveExecutablePath();
+      if (missingText)
+        throw new Error(missingText);
+      firefoxExecutable = executablePath;
+    }
+    const stdio = ['pipe', 'pipe', 'pipe'];
+    const firefoxProcess = childProcess.spawn(
+        firefoxExecutable,
+        firefoxArguments,
+        {
+          // On non-windows platforms, `detached: false` makes child process a leader of a new
+          // process group, making it possible to kill child process tree with `.kill(-pid)` command.
+          // @see https://nodejs.org/api/child_process.html#child_process_options_detached
+          detached: process.platform !== 'win32',
+          stdio,
+          // On linux Juggler ships the libstdc++ it was linked against.
+          env: os.platform() === 'linux' ? {
+            ...env,
+            LD_LIBRARY_PATH: `${path.dirname(firefoxExecutable)}:${process.env.LD_LIBRARY_PATH}`,
+          } : env,
+        }
+    );
+
+    if (dumpio) {
+      firefoxProcess.stderr.pipe(process.stderr);
+      firefoxProcess.stdout.pipe(process.stdout);
+    }
+
+    let firefoxClosed = false;
+    const waitForFirefoxToClose = new Promise((fulfill, reject) => {
+      firefoxProcess.once('close', () => {
+        firefoxClosed = true;
+        // Cleanup as processes exit.
+        if (temporaryProfileDir) {
+          removeFolderAsync(temporaryProfileDir)
+              .then(() => fulfill())
+              .catch(err => console.error(err));
+        } else {
+          fulfill();
+        }
+      });
+    });
+
+    const listeners = [ helper.addEventListener(process, 'close', killFirefox) ];
+    if (handleSIGINT)
+      listeners.push(helper.addEventListener(process, 'SIGINT', () => { killFirefox(); process.exit(130); }));
+    if (handleSIGTERM)
+      listeners.push(helper.addEventListener(process, 'SIGTERM', gracefullyCloseFirefox));
+    if (handleSIGHUP)
+      listeners.push(helper.addEventListener(process, 'SIGHUP', gracefullyCloseFirefox));
+    let connection: Connection | null = null;
+    try {
+      const url = await waitForWSEndpoint(firefoxProcess, timeout);
+      const transport = await WebSocketTransport.create(url);
+      connection = new Connection(url, transport, slowMo);
+      const browser = await Browser.create(connection, defaultViewport, firefoxProcess, gracefullyCloseFirefox);
+      if (ignoreHTTPSErrors)
+        await connection.send('Browser.setIgnoreHTTPSErrors', {enabled: true});
+      await browser.waitForTarget(t => t.type() === 'page');
+      return browser;
+    } catch (e) {
+      killFirefox();
+      throw e;
+    }
+
+    function gracefullyCloseFirefox() {
+      helper.removeEventListeners(listeners);
+      if (temporaryProfileDir) {
+        killFirefox();
+      } else if (connection) {
+        connection.send('Browser.close').catch(error => {
+          debugError(error);
+          killFirefox();
+        });
+      }
+      return waitForFirefoxToClose;
+    }
+
+    // This method has to be sync to be used as 'exit' event handler.
+    function killFirefox() {
+      helper.removeEventListeners(listeners);
+      if (firefoxProcess.pid && !firefoxProcess.killed && !firefoxClosed) {
+        // Force kill chrome.
+        try {
+          if (process.platform === 'win32')
+            childProcess.execSync(`taskkill /pid ${firefoxProcess.pid} /T /F`);
+          else
+            process.kill(-firefoxProcess.pid, 'SIGKILL');
+        } catch (e) {
+          // the process might have already stopped
+        }
+      }
+      // Attempt to remove temporary profile directory to avoid littering.
+      try {
+        removeFolder.sync(temporaryProfileDir);
+      } catch (e) { }
+    }
+  }
+
+  async connect(options: any = {}): Promise<Browser> {
+    const {
+      browserWSEndpoint,
+      slowMo = 0,
+      defaultViewport = {width: 800, height: 600},
+      ignoreHTTPSErrors = false,
+    } = options;
+    let connection = null;
+    const transport = await WebSocketTransport.create(browserWSEndpoint);
+    connection = new Connection(browserWSEndpoint, transport, slowMo);
+    const browser = await Browser.create(connection, defaultViewport, null, () => connection.send('Browser.close').catch(debugError));
+    if (ignoreHTTPSErrors)
+      await connection.send('Browser.setIgnoreHTTPSErrors', {enabled: true});
+    return browser;
+  }
+
+  executablePath(): string {
+    return this._resolveExecutablePath().executablePath;
+  }
+
+  _resolveExecutablePath() {
+    const browserFetcher = new BrowserFetcher(this._projectRoot, { browser: 'firefox' });
+    const revisionInfo = browserFetcher.revisionInfo(this._preferredRevision);
+    const missingText = !revisionInfo.local ? `Firefox revision is not downloaded. Run "npm install" or "yarn install"` : null;
+    return {executablePath: revisionInfo.executablePath, missingText};
+  }
+}
+
+function waitForWSEndpoint(firefoxProcess: import('child_process').ChildProcess, timeout: number): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const rl = readline.createInterface({ input: firefoxProcess.stdout });
+    let stderr = '';
+    const listeners = [
+      helper.addEventListener(rl, 'line', onLine),
+      helper.addEventListener(rl, 'close', () => onClose()),
+      helper.addEventListener(firefoxProcess, 'error', error => onClose(error))
+    ];
+    const timeoutId = timeout ? setTimeout(onTimeout, timeout) : 0;
+
+    function onClose(error?: Error) {
+      cleanup();
+      reject(new Error([
+        'Failed to launch Firefox!' + (error ? ' ' + error.message : ''),
+        stderr,
+        '',
+      ].join('\n')));
+    }
+
+    function onTimeout() {
+      cleanup();
+      reject(new TimeoutError(`Timed out after ${timeout} ms while trying to connect to Firefox!`));
+    }
+
+    function onLine(line: string) {
+      stderr += line + '\n';
+      const match = line.match(/^Juggler listening on (ws:\/\/.*)$/);
+      if (!match)
+        return;
+      cleanup();
+      resolve(match[1]);
+    }
+
+    function cleanup() {
+      if (timeoutId)
+        clearTimeout(timeoutId);
+      helper.removeEventListeners(listeners);
+    }
+  });
+}
--- a/src/firefox/NavigationWatchdog.ts
+++ b/src/firefox/NavigationWatchdog.ts
@ -0,0 +1,125 @@
+import { helper, RegisteredListener } from '../helper';
+import { JugglerSession, JugglerSessionEvents } from './Connection';
+import { Frame, FrameManagerEvents } from './FrameManager';
+import { NetworkManager, NetworkManagerEvents } from './NetworkManager';
+
+export class NextNavigationWatchdog {
+  private _navigatedFrame: Frame;
+  private _promise: Promise<unknown>;
+  private _resolveCallback: (value?: unknown) => void;
+  private _navigation: {navigationId: number|null, url?: string} = null;
+  private _eventListeners: RegisteredListener[];
+  constructor(session : JugglerSession, navigatedFrame : Frame) {
+    this._navigatedFrame = navigatedFrame;
+    this._promise = new Promise(x => this._resolveCallback = x);
+    this._eventListeners = [
+      helper.addEventListener(session, 'Page.navigationStarted', this._onNavigationStarted.bind(this)),
+      helper.addEventListener(session, 'Page.sameDocumentNavigation', this._onSameDocumentNavigation.bind(this)),
+    ];
+  }
+
+  promise() {
+    return this._promise;
+  }
+
+  navigation() {
+    return this._navigation;
+  }
+
+  _onNavigationStarted(params) {
+    if (params.frameId === this._navigatedFrame._frameId) {
+      this._navigation = {
+        navigationId: params.navigationId,
+        url: params.url,
+      };
+      this._resolveCallback();
+    }
+  }
+
+  _onSameDocumentNavigation(params) {
+    if (params.frameId === this._navigatedFrame._frameId) {
+      this._navigation = {
+        navigationId: null,
+      };
+      this._resolveCallback();
+    }
+  }
+
+  dispose() {
+    helper.removeEventListeners(this._eventListeners);
+  }
+}
+
+export class NavigationWatchdog {
+  private _navigatedFrame: Frame;
+  private _targetNavigationId: any;
+  private _firedEvents: any;
+  private _targetURL: any;
+  private _promise: Promise<unknown>;
+  private _resolveCallback: (value?: unknown) => void;
+  private _navigationRequest: any;
+  private _eventListeners: RegisteredListener[];
+  constructor(session : JugglerSession, navigatedFrame : Frame, networkManager : NetworkManager, targetNavigationId, targetURL, firedEvents) {
+    this._navigatedFrame = navigatedFrame;
+    this._targetNavigationId = targetNavigationId;
+    this._firedEvents = firedEvents;
+    this._targetURL = targetURL;
+
+    this._promise = new Promise(x => this._resolveCallback = x);
+    this._navigationRequest = null;
+
+    const check = this._checkNavigationComplete.bind(this);
+    this._eventListeners = [
+      helper.addEventListener(session, JugglerSessionEvents.Disconnected, () => this._resolveCallback(new Error('Navigation failed because browser has disconnected!'))),
+      helper.addEventListener(session, 'Page.eventFired', check),
+      helper.addEventListener(session, 'Page.frameAttached', check),
+      helper.addEventListener(session, 'Page.frameDetached', check),
+      helper.addEventListener(session, 'Page.navigationStarted', check),
+      helper.addEventListener(session, 'Page.navigationCommitted', check),
+      helper.addEventListener(session, 'Page.navigationAborted', this._onNavigationAborted.bind(this)),
+      helper.addEventListener(networkManager, NetworkManagerEvents.Request, this._onRequest.bind(this)),
+      helper.addEventListener(navigatedFrame._frameManager, FrameManagerEvents.FrameDetached, check),
+    ];
+    check();
+  }
+
+  _onRequest(request) {
+    if (request.frame() !== this._navigatedFrame || !request.isNavigationRequest())
+      return;
+    this._navigationRequest = request;
+  }
+
+  navigationResponse() {
+    return this._navigationRequest ? this._navigationRequest.response() : null;
+  }
+
+  _checkNavigationComplete() {
+    if (this._navigatedFrame.isDetached())
+      this._resolveCallback(new Error('Navigating frame was detached'));
+    else if (this._navigatedFrame._lastCommittedNavigationId === this._targetNavigationId
+        && checkFiredEvents(this._navigatedFrame, this._firedEvents))
+      this._resolveCallback(null);
+
+
+    function checkFiredEvents(frame, firedEvents) {
+      for (const subframe of frame._children) {
+        if (!checkFiredEvents(subframe, firedEvents))
+          return false;
+      }
+      return firedEvents.every(event => frame._firedEvents.has(event));
+    }
+  }
+
+  _onNavigationAborted(params) {
+    if (params.frameId === this._navigatedFrame._frameId && params.navigationId === this._targetNavigationId)
+      this._resolveCallback(new Error('Navigation to ' + this._targetURL + ' failed: ' + params.errorText));
+  }
+
+  promise() {
+    return this._promise;
+  }
+
+  dispose() {
+    helper.removeEventListeners(this._eventListeners);
+  }
+}
--- a/src/firefox/NetworkManager.ts
+++ b/src/firefox/NetworkManager.ts
@ -0,0 +1,365 @@
+import {helper, assert, debugError} from '../helper';
+import {EventEmitter} from 'events';
+import { JugglerSession } from './Connection';
+import { FrameManager } from './FrameManager';
+
+export const NetworkManagerEvents = {
+  RequestFailed: Symbol('NetworkManagerEvents.RequestFailed'),
+  RequestFinished: Symbol('NetworkManagerEvents.RequestFinished'),
+  Request: Symbol('NetworkManagerEvents.Request'),
+  Response: Symbol('NetworkManagerEvents.Response'),
+};
+
+export class NetworkManager extends EventEmitter {
+  private _session: JugglerSession;
+  private _requests: Map<any, any>;
+  private _frameManager: FrameManager;
+  private _eventListeners: any[];
+  constructor(session) {
+    super();
+    this._session = session;
+
+    this._requests = new Map();
+    this._frameManager = null;
+
+    this._eventListeners = [
+      helper.addEventListener(session, 'Network.requestWillBeSent', this._onRequestWillBeSent.bind(this)),
+      helper.addEventListener(session, 'Network.responseReceived', this._onResponseReceived.bind(this)),
+      helper.addEventListener(session, 'Network.requestFinished', this._onRequestFinished.bind(this)),
+      helper.addEventListener(session, 'Network.requestFailed', this._onRequestFailed.bind(this)),
+    ];
+  }
+
+  dispose() {
+    helper.removeEventListeners(this._eventListeners);
+  }
+
+  setFrameManager(frameManager: FrameManager) {
+    this._frameManager = frameManager;
+  }
+
+  async setExtraHTTPHeaders(headers) {
+    const array = [];
+    for (const [name, value] of Object.entries(headers)) {
+      assert(helper.isString(value), `Expected value of header "${name}" to be String, but "${typeof value}" is found.`);
+      array.push({name, value});
+    }
+    await this._session.send('Network.setExtraHTTPHeaders', {headers: array});
+  }
+
+  async setRequestInterception(enabled) {
+    await this._session.send('Network.setRequestInterception', {enabled});
+  }
+
+  _onRequestWillBeSent(event) {
+    const redirected = event.redirectedFrom ? this._requests.get(event.redirectedFrom) : null;
+    const frame = redirected ? redirected.frame() : (this._frameManager && event.frameId ? this._frameManager.frame(event.frameId) : null);
+    if (!frame)
+      return;
+    let redirectChain = [];
+    if (redirected) {
+      redirectChain = redirected._redirectChain;
+      redirectChain.push(redirected);
+      this._requests.delete(redirected._id);
+    }
+    const request = new Request(this._session, frame, redirectChain, event);
+    this._requests.set(request._id, request);
+    this.emit(NetworkManagerEvents.Request, request);
+  }
+
+  _onResponseReceived(event) {
+    const request = this._requests.get(event.requestId);
+    if (!request)
+      return;
+    const response = new Response(this._session, request, event);
+    request._response = response;
+    this.emit(NetworkManagerEvents.Response, response);
+  }
+
+  _onRequestFinished(event) {
+    const request = this._requests.get(event.requestId);
+    if (!request)
+      return;
+    // Keep redirected requests in the map for future reference in redirectChain.
+    const isRedirected = request.response().status() >= 300 && request.response().status() <= 399;
+    if (isRedirected) {
+      request.response()._bodyLoadedPromiseFulfill.call(null, new Error('Response body is unavailable for redirect responses'));
+    } else {
+      this._requests.delete(request._id);
+      request.response()._bodyLoadedPromiseFulfill.call(null);
+    }
+    this.emit(NetworkManagerEvents.RequestFinished, request);
+  }
+
+  _onRequestFailed(event) {
+    const request = this._requests.get(event.requestId);
+    if (!request)
+      return;
+    this._requests.delete(request._id);
+    if (request.response())
+      request.response()._bodyLoadedPromiseFulfill.call(null);
+    request._errorText = event.errorCode;
+    this.emit(NetworkManagerEvents.RequestFailed, request);
+  }
+}
+
+const causeToResourceType = {
+  TYPE_INVALID: 'other',
+  TYPE_OTHER: 'other',
+  TYPE_SCRIPT: 'script',
+  TYPE_IMAGE: 'image',
+  TYPE_STYLESHEET: 'stylesheet',
+  TYPE_OBJECT: 'other',
+  TYPE_DOCUMENT: 'document',
+  TYPE_SUBDOCUMENT: 'document',
+  TYPE_REFRESH: 'document',
+  TYPE_XBL: 'other',
+  TYPE_PING: 'other',
+  TYPE_XMLHTTPREQUEST: 'xhr',
+  TYPE_OBJECT_SUBREQUEST: 'other',
+  TYPE_DTD: 'other',
+  TYPE_FONT: 'font',
+  TYPE_MEDIA: 'media',
+  TYPE_WEBSOCKET: 'websocket',
+  TYPE_CSP_REPORT: 'other',
+  TYPE_XSLT: 'other',
+  TYPE_BEACON: 'other',
+  TYPE_FETCH: 'fetch',
+  TYPE_IMAGESET: 'images',
+  TYPE_WEB_MANIFEST: 'manifest',
+};
+
+export class Request {
+  _id(_id: any, request: Request) {
+    throw new Error('Method not implemented.');
+  }
+  _session: any;
+  _frame: any;
+  _redirectChain: any;
+  _url: any;
+  _postData: any;
+  _suspended: any;
+  _response: any;
+  _errorText: any;
+  _isNavigationRequest: any;
+  _method: any;
+  _resourceType: any;
+  _headers: {};
+  _interceptionHandled: boolean;
+  constructor(session, frame, redirectChain, payload) {
+    this._session = session;
+    this._frame = frame;
+    this._id = payload.requestId;
+    this._redirectChain = redirectChain;
+    this._url = payload.url;
+    this._postData = payload.postData;
+    this._suspended = payload.suspended;
+    this._response = null;
+    this._errorText = null;
+    this._isNavigationRequest = payload.isNavigationRequest;
+    this._method = payload.method;
+    this._resourceType = causeToResourceType[payload.cause] || 'other';
+    this._headers = {};
+    this._interceptionHandled = false;
+    for (const {name, value} of payload.headers)
+      this._headers[name.toLowerCase()] = value;
+  }
+
+  failure() {
+    return this._errorText ? {errorText: this._errorText} : null;
+  }
+
+  async continue(overrides: any = {}) {
+    assert(!overrides.url, 'Playwright-Firefox does not support overriding URL');
+    assert(!overrides.method, 'Playwright-Firefox does not support overriding method');
+    assert(!overrides.postData, 'Playwright-Firefox does not support overriding postData');
+    assert(this._suspended, 'Request Interception is not enabled!');
+    assert(!this._interceptionHandled, 'Request is already handled!');
+    this._interceptionHandled = true;
+    const {
+      headers,
+    } = overrides;
+    await this._session.send('Network.resumeSuspendedRequest', {
+      requestId: this._id,
+      headers: headers ? Object.entries(headers).filter(([, value]) => !Object.is(value, undefined)).map(([name, value]) => ({name, value})) : undefined,
+    }).catch(error => {
+      debugError(error);
+    });
+  }
+
+  async abort() {
+    assert(this._suspended, 'Request Interception is not enabled!');
+    assert(!this._interceptionHandled, 'Request is already handled!');
+    this._interceptionHandled = true;
+    await this._session.send('Network.abortSuspendedRequest', {
+      requestId: this._id,
+    }).catch(error => {
+      debugError(error);
+    });
+  }
+
+  postData() {
+    return this._postData;
+  }
+
+  headers() {
+    return {...this._headers};
+  }
+
+  redirectChain() {
+    return this._redirectChain.slice();
+  }
+
+  resourceType() {
+    return this._resourceType;
+  }
+
+  url() {
+    return this._url;
+  }
+
+  method() {
+    return this._method;
+  }
+
+  isNavigationRequest() {
+    return this._isNavigationRequest;
+  }
+
+  frame() {
+    return this._frame;
+  }
+
+  response() {
+    return this._response;
+  }
+}
+
+export class Response {
+  _session: any;
+  _request: any;
+  _remoteIPAddress: any;
+  _remotePort: any;
+  _status: any;
+  _statusText: any;
+  _headers: {};
+  _securityDetails: SecurityDetails;
+  _bodyLoadedPromise: Promise<unknown>;
+  _bodyLoadedPromiseFulfill: (value?: unknown) => void;
+  _contentPromise: any;
+  constructor(session, request, payload) {
+    this._session = session;
+    this._request = request;
+    this._remoteIPAddress = payload.remoteIPAddress;
+    this._remotePort = payload.remotePort;
+    this._status = payload.status;
+    this._statusText = payload.statusText;
+    this._headers = {};
+    this._securityDetails = payload.securityDetails ? new SecurityDetails(payload.securityDetails) : null;
+    for (const {name, value} of payload.headers)
+      this._headers[name.toLowerCase()] = value;
+    this._bodyLoadedPromise = new Promise(fulfill => {
+      this._bodyLoadedPromiseFulfill = fulfill;
+    });
+  }
+
+  buffer(): Promise<Buffer> {
+    if (!this._contentPromise) {
+      this._contentPromise = this._bodyLoadedPromise.then(async error => {
+        if (error)
+          throw error;
+        const response = await this._session.send('Network.getResponseBody', {
+          requestId: this._request._id
+        });
+        if (response.evicted)
+          throw new Error(`Response body for ${this._request.method()} ${this._request.url()} was evicted!`);
+        return Buffer.from(response.base64body, 'base64');
+      });
+    }
+    return this._contentPromise;
+  }
+
+  async text(): Promise<string> {
+    const content = await this.buffer();
+    return content.toString('utf8');
+  }
+
+  async json(): Promise<object> {
+    const content = await this.text();
+    return JSON.parse(content);
+  }
+
+  securityDetails() {
+    return this._securityDetails;
+  }
+
+  headers() {
+    return {...this._headers};
+  }
+
+  status() {
+    return this._status;
+  }
+
+  statusText() {
+    return this._statusText;
+  }
+
+  ok() {
+    return this._status >= 200 && this._status <= 299;
+  }
+
+  remoteAddress() {
+    return {
+      ip: this._remoteIPAddress,
+      port: this._remotePort,
+    };
+  }
+
+  frame() {
+    return this._request.frame();
+  }
+
+  url() {
+    return this._request.url();
+  }
+
+  request() {
+    return this._request;
+  }
+}
+
+export class SecurityDetails {
+  _subjectName: string;
+  _issuer: string;
+  _validFrom: number;
+  _validTo: number;
+  _protocol: string;
+  constructor(securityPayload: any) {
+    this._subjectName = securityPayload['subjectName'];
+    this._issuer = securityPayload['issuer'];
+    this._validFrom = securityPayload['validFrom'];
+    this._validTo = securityPayload['validTo'];
+    this._protocol = securityPayload['protocol'];
+  }
+
+  subjectName(): string {
+    return this._subjectName;
+  }
+
+  issuer(): string {
+    return this._issuer;
+  }
+
+  validFrom(): number {
+    return this._validFrom;
+  }
+
+  validTo(): number {
+    return this._validTo;
+  }
+
+  protocol(): string {
+    return this._protocol;
+  }
+}
--- a/src/firefox/Page.ts
+++ b/src/firefox/Page.ts
@ -0,0 +1,640 @@
+import { JSHandle, ElementHandle } from './JSHandle';
+
+import {RegisteredListener, helper, debugError, assert} from '../helper';
+import {Keyboard, Mouse, Touchscreen} from './Input';
+import {Dialog} from './Dialog';
+import {TimeoutError} from '../Errors';
+import * as fs from 'fs';
+import * as mime from 'mime';
+import {EventEmitter} from 'events';
+import {createHandle} from './JSHandle';
+import {Connection, JugglerSession, JugglerSessionEvents} from './Connection';
+import {FrameManager, normalizeWaitUntil, FrameManagerEvents} from './FrameManager';
+import {NetworkManager, Request, Response, NetworkManagerEvents} from './NetworkManager';
+import {TimeoutSettings} from '../TimeoutSettings';
+import {NavigationWatchdog} from './NavigationWatchdog';
+import {Accessibility} from './Accessibility';
+import { Target, BrowserContext } from './Browser';
+import { Events } from '../Events';
+
+const writeFileAsync = helper.promisify(fs.writeFile);
+
+export class Page extends EventEmitter {
+  private _timeoutSettings: TimeoutSettings;
+  private _session: JugglerSession;
+  private _target: Target;
+  private _keyboard: Keyboard;
+  private _mouse: Mouse;
+  private _touchscreen: Touchscreen;
+  private _accessibility: Accessibility;
+  private _closed: boolean;
+  private _pageBindings: Map<string, Function>;
+  private _networkManager: NetworkManager;
+  private _frameManager: FrameManager;
+  private _eventListeners: RegisteredListener[];
+  private _viewport: Viewport;
+  private _disconnectPromise: Promise<Error>;
+  emulateMedia: (type: string) => Promise<void>;
+  static async create(session, target: Target, defaultViewport: Viewport | null) {
+    const page = new Page(session, target);
+    await Promise.all([
+      session.send('Runtime.enable'),
+      session.send('Network.enable'),
+      session.send('Page.enable'),
+    ]);
+
+    if (defaultViewport)
+      await page.setViewport(defaultViewport);
+    return page;
+  }
+
+  constructor(session: JugglerSession, target: Target) {
+    super();
+    this._timeoutSettings = new TimeoutSettings();
+    this._session = session;
+    this._target = target;
+    this._keyboard = new Keyboard(session);
+    this._mouse = new Mouse(session, this._keyboard);
+    this._touchscreen = new Touchscreen(session, this._keyboard, this._mouse);
+    this._accessibility = new Accessibility(session);
+    this._closed = false;
+    this._pageBindings = new Map();
+    this._networkManager = new NetworkManager(session);
+    this._frameManager = new FrameManager(session, this, this._networkManager, this._timeoutSettings);
+    this._networkManager.setFrameManager(this._frameManager);
+    this._eventListeners = [
+      helper.addEventListener(this._session, 'Page.uncaughtError', this._onUncaughtError.bind(this)),
+      helper.addEventListener(this._session, 'Runtime.console', this._onConsole.bind(this)),
+      helper.addEventListener(this._session, 'Page.dialogOpened', this._onDialogOpened.bind(this)),
+      helper.addEventListener(this._session, 'Page.bindingCalled', this._onBindingCalled.bind(this)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.Load, () => this.emit(Events.Page.Load)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.DOMContentLoaded, () => this.emit(Events.Page.DOMContentLoaded)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.FrameAttached, frame => this.emit(Events.Page.FrameAttached, frame)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.FrameDetached, frame => this.emit(Events.Page.FrameDetached, frame)),
+      helper.addEventListener(this._frameManager, FrameManagerEvents.FrameNavigated, frame => this.emit(Events.Page.FrameNavigated, frame)),
+      helper.addEventListener(this._networkManager, NetworkManagerEvents.Request, request => this.emit(Events.Page.Request, request)),
+      helper.addEventListener(this._networkManager, NetworkManagerEvents.Response, response => this.emit(Events.Page.Response, response)),
+      helper.addEventListener(this._networkManager, NetworkManagerEvents.RequestFinished, request => this.emit(Events.Page.RequestFinished, request)),
+      helper.addEventListener(this._networkManager, NetworkManagerEvents.RequestFailed, request => this.emit(Events.Page.RequestFailed, request)),
+    ];
+    this._viewport = null;
+    this._target._isClosedPromise.then(() => {
+      this._closed = true;
+      this._frameManager.dispose();
+      this._networkManager.dispose();
+      helper.removeEventListeners(this._eventListeners);
+      this.emit(Events.Page.Close);
+    });
+  }
+
+  async cookies(...urls: Array<string>): Promise<Array<any>> {
+    const connection = Connection.fromSession(this._session);
+    const {cookies} = await connection.send('Browser.getCookies', {
+      browserContextId: this._target._context._browserContextId || undefined,
+      urls: urls.length ? urls : [this.url()]
+    });
+    // Firefox's cookies are missing sameSite when it is 'None'
+    return cookies.map(cookie => ({sameSite: 'None', ...cookie}));
+  }
+
+  async deleteCookie(...cookies: Array<any>) {
+    const pageURL = this.url();
+    const items = [];
+    for (const cookie of cookies) {
+      const item = {
+        url: cookie.url,
+        domain: cookie.domain,
+        path: cookie.path,
+        name: cookie.name,
+      };
+      if (!item.url && pageURL.startsWith('http'))
+        item.url = pageURL;
+      items.push(item);
+    }
+
+    const connection = Connection.fromSession(this._session);
+    await connection.send('Browser.deleteCookies', {
+      browserContextId: this._target._context._browserContextId || undefined,
+      cookies: items,
+    });
+  }
+
+  async setCookie(...cookies: Array<any>) {
+    const pageURL = this.url();
+    const startsWithHTTP = pageURL.startsWith('http');
+    const items = cookies.map(cookie => {
+      const item = Object.assign({}, cookie);
+      if (!item.url && startsWithHTTP)
+        item.url = pageURL;
+      assert(item.url !== 'about:blank', `Blank page can not have cookie "${item.name}"`);
+      assert(!String.prototype.startsWith.call(item.url || '', 'data:'), `Data URL page can not have cookie "${item.name}"`);
+      return item;
+    });
+    await this.deleteCookie(...items);
+    if (items.length) {
+      const connection = Connection.fromSession(this._session);
+      await connection.send('Browser.setCookies', {
+        browserContextId: this._target._context._browserContextId || undefined,
+        cookies: items
+      });
+    }
+  }
+
+  async setRequestInterception(enabled) {
+    await this._networkManager.setRequestInterception(enabled);
+  }
+
+  async setExtraHTTPHeaders(headers) {
+    await this._networkManager.setExtraHTTPHeaders(headers);
+  }
+
+  async emulateMediaType(type: string | null) {
+    assert(type === 'screen' || type === 'print' || type === null, 'Unsupported media type: ' + type);
+    await this._session.send('Page.setEmulatedMedia', {media: type || ''});
+  }
+
+  async exposeFunction(name: string, playwrightFunction: Function) {
+    if (this._pageBindings.has(name))
+      throw new Error(`Failed to add page binding with name ${name}: window['${name}'] already exists!`);
+    this._pageBindings.set(name, playwrightFunction);
+
+    const expression = helper.evaluationString(addPageBinding, name);
+    await this._session.send('Page.addBinding', {name: name});
+    await this._session.send('Page.addScriptToEvaluateOnNewDocument', {script: expression});
+    await Promise.all(this.frames().map(frame => frame.evaluate(expression).catch(debugError)));
+
+    function addPageBinding(bindingName: string) {
+      const binding: (string) => void = window[bindingName];
+      window[bindingName] = (...args) => {
+        const me = window[bindingName];
+        let callbacks = me['callbacks'];
+        if (!callbacks) {
+          callbacks = new Map();
+          me['callbacks'] = callbacks;
+        }
+        const seq = (me['lastSeq'] || 0) + 1;
+        me['lastSeq'] = seq;
+        const promise = new Promise((resolve, reject) => callbacks.set(seq, {resolve, reject}));
+        binding(JSON.stringify({name: bindingName, seq, args}));
+        return promise;
+      };
+    }
+  }
+
+  async _onBindingCalled(event: any) {
+    const {name, seq, args} = JSON.parse(event.payload);
+    let expression = null;
+    try {
+      const result = await this._pageBindings.get(name)(...args);
+      expression = helper.evaluationString(deliverResult, name, seq, result);
+    } catch (error) {
+      if (error instanceof Error)
+        expression = helper.evaluationString(deliverError, name, seq, error.message, error.stack);
+      else
+        expression = helper.evaluationString(deliverErrorValue, name, seq, error);
+    }
+    this._session.send('Runtime.evaluate', { expression, executionContextId: event.executionContextId }).catch(debugError);
+
+    function deliverResult(name: string, seq: number, result: any) {
+      window[name]['callbacks'].get(seq).resolve(result);
+      window[name]['callbacks'].delete(seq);
+    }
+
+    function deliverError(name: string, seq: number, message: string, stack: string) {
+      const error = new Error(message);
+      error.stack = stack;
+      window[name]['callbacks'].get(seq).reject(error);
+      window[name]['callbacks'].delete(seq);
+    }
+
+    function deliverErrorValue(name: string, seq: number, value: any) {
+      window[name]['callbacks'].get(seq).reject(value);
+      window[name]['callbacks'].delete(seq);
+    }
+  }
+
+  _sessionClosePromise() {
+    if (!this._disconnectPromise)
+      this._disconnectPromise = new Promise<Error>(fulfill => this._session.once(JugglerSessionEvents.Disconnected, () => fulfill(new Error('Target closed'))));
+    return this._disconnectPromise;
+  }
+
+  async waitForRequest(urlOrPredicate: (string | Function), options: { timeout?: number; } | undefined = {}): Promise<Request> {
+    const {
+      timeout = this._timeoutSettings.timeout(),
+    } = options;
+    return helper.waitForEvent(this._networkManager, NetworkManagerEvents.Request, request => {
+      if (helper.isString(urlOrPredicate))
+        return (urlOrPredicate === request.url());
+      if (typeof urlOrPredicate === 'function')
+        return !!(urlOrPredicate(request));
+      return false;
+    }, timeout, this._sessionClosePromise());
+  }
+
+  async waitForResponse(urlOrPredicate: (string | Function), options: { timeout?: number; } | undefined = {}): Promise<Response> {
+    const {
+      timeout = this._timeoutSettings.timeout(),
+    } = options;
+    return helper.waitForEvent(this._networkManager, NetworkManagerEvents.Response, response => {
+      if (helper.isString(urlOrPredicate))
+        return (urlOrPredicate === response.url());
+      if (typeof urlOrPredicate === 'function')
+        return !!(urlOrPredicate(response));
+      return false;
+    }, timeout, this._sessionClosePromise());
+  }
+
+  setDefaultNavigationTimeout(timeout: number) {
+    this._timeoutSettings.setDefaultNavigationTimeout(timeout);
+  }
+
+  setDefaultTimeout(timeout: number) {
+    this._timeoutSettings.setDefaultTimeout(timeout);
+  }
+
+  async setUserAgent(userAgent: string) {
+    await this._session.send('Page.setUserAgent', {userAgent});
+  }
+
+  async setJavaScriptEnabled(enabled) {
+    await this._session.send('Page.setJavascriptEnabled', {enabled});
+  }
+
+  async setCacheEnabled(enabled) {
+    await this._session.send('Page.setCacheDisabled', {cacheDisabled: !enabled});
+  }
+
+  async emulate(options: { viewport: Viewport; userAgent: string; }) {
+    await Promise.all([
+      this.setViewport(options.viewport),
+      this.setUserAgent(options.userAgent),
+    ]);
+  }
+
+  browserContext(): BrowserContext {
+    return this._target.browserContext();
+  }
+
+  _onUncaughtError(params) {
+    const error = new Error(params.message);
+    error.stack = params.stack;
+    this.emit(Events.Page.PageError, error);
+  }
+
+  viewport() {
+    return this._viewport;
+  }
+
+  async setViewport(viewport: Viewport) {
+    const {
+      width,
+      height,
+      isMobile = false,
+      deviceScaleFactor = 1,
+      hasTouch = false,
+      isLandscape = false,
+    } = viewport;
+    await this._session.send('Page.setViewport', {
+      viewport: { width, height, isMobile, deviceScaleFactor, hasTouch, isLandscape },
+    });
+    const oldIsMobile = this._viewport ? this._viewport.isMobile : false;
+    const oldHasTouch = this._viewport ? this._viewport.hasTouch : false;
+    this._viewport = viewport;
+    if (oldIsMobile !== isMobile || oldHasTouch !== hasTouch)
+      await this.reload();
+  }
+
+  async evaluateOnNewDocument(pageFunction: Function | string, ...args: Array<any>) {
+    const script = helper.evaluationString(pageFunction, ...args);
+    await this._session.send('Page.addScriptToEvaluateOnNewDocument', { script });
+  }
+
+  browser() {
+    return this._target.browser();
+  }
+
+  target() {
+    return this._target;
+  }
+
+  url() {
+    return this._frameManager.mainFrame().url();
+  }
+
+  frames() {
+    return this._frameManager.frames();
+  }
+
+  _onDialogOpened(params) {
+    this.emit(Events.Page.Dialog, new Dialog(this._session, params));
+  }
+
+  mainFrame() {
+    return this._frameManager.mainFrame();
+  }
+
+  get accessibility() {
+    return this._accessibility;
+  }
+
+  get keyboard(){
+    return this._keyboard;
+  }
+
+  get mouse(){
+    return this._mouse;
+  }
+
+  get touchscreen(){
+    return this._touchscreen;
+  }
+
+  async waitForNavigation(options: { timeout?: number; waitUntil?: string | Array<string>; } = {}) {
+    return this._frameManager.mainFrame().waitForNavigation(options);
+  }
+
+  async goto(url: string, options: { timeout?: number; waitUntil?: string | Array<string>; } = {}) {
+    return this._frameManager.mainFrame().goto(url, options);
+  }
+
+  async goBack(options: { timeout?: number; waitUntil?: string | Array<string>; } = {}) {
+    const {
+      timeout = this._timeoutSettings.navigationTimeout(),
+      waitUntil = ['load'],
+    } = options;
+    const frame = this._frameManager.mainFrame();
+    const normalizedWaitUntil = normalizeWaitUntil(waitUntil);
+    const {navigationId, navigationURL} = await this._session.send('Page.goBack', {
+      frameId: frame._frameId,
+    });
+    if (!navigationId)
+      return null;
+
+    const timeoutError = new TimeoutError('Navigation timeout of ' + timeout + ' ms exceeded');
+    let timeoutCallback;
+    const timeoutPromise = new Promise(resolve => timeoutCallback = resolve.bind(null, timeoutError));
+    const timeoutId = timeout ? setTimeout(timeoutCallback, timeout) : null;
+
+    const watchDog = new NavigationWatchdog(this._session, frame, this._networkManager, navigationId, navigationURL, normalizedWaitUntil);
+    const error = await Promise.race([
+      timeoutPromise,
+      watchDog.promise(),
+    ]);
+    watchDog.dispose();
+    clearTimeout(timeoutId);
+    if (error)
+      throw error;
+    return watchDog.navigationResponse();
+  }
+
+  async goForward(options: { timeout?: number; waitUntil?: string | Array<string>; } = {}) {
+    const {
+      timeout = this._timeoutSettings.navigationTimeout(),
+      waitUntil = ['load'],
+    } = options;
+    const frame = this._frameManager.mainFrame();
+    const normalizedWaitUntil = normalizeWaitUntil(waitUntil);
+    const {navigationId, navigationURL} = await this._session.send('Page.goForward', {
+      frameId: frame._frameId,
+    });
+    if (!navigationId)
+      return null;
+
+    const timeoutError = new TimeoutError('Navigation timeout of ' + timeout + ' ms exceeded');
+    let timeoutCallback;
+    const timeoutPromise = new Promise(resolve => timeoutCallback = resolve.bind(null, timeoutError));
+    const timeoutId = timeout ? setTimeout(timeoutCallback, timeout) : null;
+
+    const watchDog = new NavigationWatchdog(this._session, frame, this._networkManager, navigationId, navigationURL, normalizedWaitUntil);
+    const error = await Promise.race([
+      timeoutPromise,
+      watchDog.promise(),
+    ]);
+    watchDog.dispose();
+    clearTimeout(timeoutId);
+    if (error)
+      throw error;
+    return watchDog.navigationResponse();
+  }
+
+  async reload(options: { timeout?: number; waitUntil?: string | Array<string>; } = {}) {
+    const {
+      timeout = this._timeoutSettings.navigationTimeout(),
+      waitUntil = ['load'],
+    } = options;
+    const frame = this._frameManager.mainFrame();
+    const normalizedWaitUntil = normalizeWaitUntil(waitUntil);
+    const {navigationId, navigationURL} = await this._session.send('Page.reload', {
+      frameId: frame._frameId,
+    });
+    if (!navigationId)
+      return null;
+
+    const timeoutError = new TimeoutError('Navigation timeout of ' + timeout + ' ms exceeded');
+    let timeoutCallback;
+    const timeoutPromise = new Promise(resolve => timeoutCallback = resolve.bind(null, timeoutError));
+    const timeoutId = timeout ? setTimeout(timeoutCallback, timeout) : null;
+
+    const watchDog = new NavigationWatchdog(this._session, frame, this._networkManager, navigationId, navigationURL, normalizedWaitUntil);
+    const error = await Promise.race([
+      timeoutPromise,
+      watchDog.promise(),
+    ]);
+    watchDog.dispose();
+    clearTimeout(timeoutId);
+    if (error)
+      throw error;
+    return watchDog.navigationResponse();
+  }
+
+  async screenshot(options: { fullPage?: boolean; clip?: { width: number; height: number; x: number; y: number; }; encoding?: string; path?: string; } = {}): Promise<string | Buffer> {
+    const {data} = await this._session.send('Page.screenshot', {
+      mimeType: getScreenshotMimeType(options),
+      fullPage: options.fullPage,
+      clip: processClip(options.clip),
+    });
+    const buffer = options.encoding === 'base64' ? data : Buffer.from(data, 'base64');
+    if (options.path)
+      await writeFileAsync(options.path, buffer);
+    return buffer;
+
+    function processClip(clip) {
+      if (!clip)
+        return undefined;
+      const x = Math.round(clip.x);
+      const y = Math.round(clip.y);
+      const width = Math.round(clip.width + clip.x - x);
+      const height = Math.round(clip.height + clip.y - y);
+      return {x, y, width, height};
+    }
+  }
+
+  async evaluate(pageFunction, ...args) {
+    return await this._frameManager.mainFrame().evaluate(pageFunction, ...args);
+  }
+
+  async addScriptTag(options: { content?: string; path?: string; type?: string; url?: string; }): Promise<ElementHandle> {
+    return await this._frameManager.mainFrame().addScriptTag(options);
+  }
+
+  async addStyleTag(options: { content?: string; path?: string; url?: string; }): Promise<ElementHandle> {
+    return await this._frameManager.mainFrame().addStyleTag(options);
+  }
+
+  async click(selector: string, options: { delay?: number; button?: string; clickCount?: number; } | undefined = {}) {
+    return await this._frameManager.mainFrame().click(selector, options);
+  }
+
+  tap(selector: string) {
+    return this.mainFrame().tap(selector);
+  }
+
+  async type(selector: string, text: string, options: { delay: (number | undefined); } | undefined) {
+    return await this._frameManager.mainFrame().type(selector, text, options);
+  }
+
+  async focus(selector: string) {
+    return await this._frameManager.mainFrame().focus(selector);
+  }
+
+  async hover(selector: string) {
+    return await this._frameManager.mainFrame().hover(selector);
+  }
+
+  async waitFor(selectorOrFunctionOrTimeout: (string | number | Function), options: { polling?: string | number; timeout?: number; visible?: boolean; hidden?: boolean; } | undefined = {}, ...args: Array<any>): Promise<JSHandle> {
+    return await this._frameManager.mainFrame().waitFor(selectorOrFunctionOrTimeout, options, ...args);
+  }
+
+  async waitForFunction(pageFunction: Function | string, options: { polling?: string | number; timeout?: number; } | undefined = {}, ...args): Promise<JSHandle> {
+    return await this._frameManager.mainFrame().waitForFunction(pageFunction, options, ...args);
+  }
+
+  async waitForSelector(selector: string, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined = {}): Promise<ElementHandle> {
+    return await this._frameManager.mainFrame().waitForSelector(selector, options);
+  }
+
+  async waitForXPath(xpath: string, options: { timeout?: number; visible?: boolean; hidden?: boolean; } | undefined = {}): Promise<ElementHandle> {
+    return await this._frameManager.mainFrame().waitForXPath(xpath, options);
+  }
+
+  async title(): Promise<string> {
+    return await this._frameManager.mainFrame().title();
+  }
+
+  async $(selector: string): Promise<ElementHandle | null> {
+    return await this._frameManager.mainFrame().$(selector);
+  }
+
+  async $$(selector: string): Promise<Array<ElementHandle>> {
+    return await this._frameManager.mainFrame().$$(selector);
+  }
+
+  async $eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    return await this._frameManager.mainFrame().$eval(selector, pageFunction, ...args);
+  }
+
+  async $$eval(selector: string, pageFunction: Function | string, ...args: Array<any>): Promise<(object | undefined)> {
+    return await this._frameManager.mainFrame().$$eval(selector, pageFunction, ...args);
+  }
+
+  async $x(expression: string): Promise<Array<ElementHandle>> {
+    return await this._frameManager.mainFrame().$x(expression);
+  }
+
+  async evaluateHandle(pageFunction, ...args) {
+    return await this._frameManager.mainFrame().evaluateHandle(pageFunction, ...args);
+  }
+
+  async select(selector: string, ...values: Array<string>): Promise<Array<string>> {
+    return await this._frameManager.mainFrame().select(selector, ...values);
+  }
+
+  async close(options: any = {}) {
+    const {
+      runBeforeUnload = false,
+    } = options;
+    await this._session.send('Page.close', { runBeforeUnload });
+    if (!runBeforeUnload)
+      await this._target._isClosedPromise;
+  }
+
+  async content() {
+    return await this._frameManager.mainFrame().content();
+  }
+
+  async setContent(html: string) {
+    return await this._frameManager.mainFrame().setContent(html);
+  }
+
+  _onConsole({type, args, executionContextId, location}) {
+    const context = this._frameManager.executionContextById(executionContextId);
+    this.emit(Events.Page.Console, new ConsoleMessage(type, args.map(arg => createHandle(context, arg)), location));
+  }
+
+  isClosed(): boolean {
+    return this._closed;
+  }
+}
+
+// Expose alias for deprecated method.
+Page.prototype.emulateMedia = Page.prototype.emulateMediaType;
+
+export class ConsoleMessage {
+  private _type: string;
+  private _args: any[];
+  private _location: any;
+  constructor(type: string, args: Array<JSHandle>, location) {
+    this._type = type;
+    this._args = args;
+    this._location = location;
+  }
+
+  location() {
+    return this._location;
+  }
+
+  type(): string {
+    return this._type;
+  }
+
+  args(): Array<JSHandle> {
+    return this._args;
+  }
+
+  text(): string {
+    return this._args.map(arg => {
+      if (arg._objectId)
+        return arg.toString();
+      return arg._deserializeValue(arg._protocolValue);
+    }).join(' ');
+  }
+}
+
+function getScreenshotMimeType(options) {
+  // options.type takes precedence over inferring the type from options.path
+  // because it may be a 0-length file with no extension created beforehand (i.e. as a temp file).
+  if (options.type) {
+    if (options.type === 'png')
+      return 'image/png';
+    if (options.type === 'jpeg')
+      return 'image/jpeg';
+    throw new Error('Unknown options.type value: ' + options.type);
+  }
+  if (options.path) {
+    const fileType = mime.getType(options.path);
+    if (fileType === 'image/png' || fileType === 'image/jpeg')
+      return fileType;
+    throw new Error('Unsupported screenshot mime type: ' + fileType);
+  }
+  return 'image/png';
+}
+
+export type Viewport = {
+  width: number;
+  height: number;
+  deviceScaleFactor?: number;
+  isMobile?: boolean;
+  isLandscape?: boolean;
+  hasTouch?: boolean;
+}
--- a/src/firefox/Playwright.ts
+++ b/src/firefox/Playwright.ts
@ -0,0 +1,66 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { Browser } from './Browser';
+import { BrowserFetcher } from './BrowserFetcher';
+import { ConnectionTransport } from '../ConnectionTransport';
+import { DeviceDescriptors } from '../DeviceDescriptors';
+import * as Errors from '../Errors';
+import { Launcher } from './Launcher';
+
+export class Playwright {
+  private _projectRoot: string;
+  private _launcher: Launcher;
+
+  constructor(projectRoot: string, preferredRevision: string) {
+    this._projectRoot = projectRoot;
+    this._launcher = new Launcher(projectRoot, preferredRevision);
+  }
+
+  launch(options: any): Promise<Browser> {
+    return this._launcher.launch(options);
+  }
+
+  connect(options: (any & {
+      browserWSEndpoint?: string;
+      browserURL?: string;
+      transport?: ConnectionTransport; })): Promise<Browser> {
+    return this._launcher.connect(options);
+  }
+
+  executablePath(): string {
+    return this._launcher.executablePath();
+  }
+
+  get devices(): any {
+    const result = DeviceDescriptors.slice();
+    for (const device of DeviceDescriptors)
+      result[device.name] = device;
+    return result;
+  }
+
+  get errors(): any {
+    return Errors;
+  }
+
+  defaultArgs(options: any | undefined): string[] {
+    return this._launcher.defaultArgs(options);
+  }
+
+  createBrowserFetcher(options: any | undefined): BrowserFetcher {
+    return new BrowserFetcher(this._projectRoot, { browser: 'firefox', ...options });
+  }
+}
--- a/src/firefox/WebSocketTransport.ts
+++ b/src/firefox/WebSocketTransport.ts
@ -0,0 +1,89 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { ConnectionTransport } from '../ConnectionTransport';
+import * as WebSocket from 'ws';
+
+export class WebSocketTransport implements ConnectionTransport {
+  _ws: WebSocket;
+  _dispatchQueue: DispatchQueue;
+  onclose?: () => void;
+  onmessage?: (message: string) => void;
+  static create(url: string): Promise<WebSocketTransport> {
+    return new Promise((resolve, reject) => {
+      const ws = new WebSocket(url, [], { perMessageDeflate: false });
+      ws.addEventListener('open', () => resolve(new WebSocketTransport(ws)));
+      ws.addEventListener('error', reject);
+    });
+  }
+
+  constructor(ws: WebSocket) {
+    this._ws = ws;
+    this._dispatchQueue = new DispatchQueue(this);
+    this._ws.addEventListener('message', event => {
+      this._dispatchQueue.enqueue(event.data);
+    });
+    this._ws.addEventListener('close', event => {
+      if (this.onclose)
+        this.onclose.call(null);
+    });
+    // Silently ignore all errors - we don't know what to do with them.
+    this._ws.addEventListener('error', () => {});
+  }
+
+  send(message: string) {
+    this._ws.send(message);
+  }
+
+  close() {
+    this._ws.close();
+  }
+}
+
+// We want to dispatch all "message" events in separate tasks
+// to make sure all message-related promises are resolved first
+// before dispatching next message.
+//
+// We cannot just use setTimeout() in Node.js here like we would
+// do in Browser - see https://github.com/nodejs/node/issues/23773
+// Thus implement a dispatch queue that enforces new tasks manually.
+class DispatchQueue {
+  _transport: ConnectionTransport;
+  _timeoutId: NodeJS.Timer = null;
+  _queue: string[] = [];
+  constructor(transport : ConnectionTransport) {
+    this._transport = transport;
+    this._dispatch = this._dispatch.bind(this);
+  }
+
+  enqueue(message: string) {
+    this._queue.push(message);
+    if (!this._timeoutId)
+      this._timeoutId = setTimeout(this._dispatch, 0);
+  }
+
+  _dispatch() {
+    const message = this._queue.shift();
+    if (this._queue.length)
+      this._timeoutId = setTimeout(this._dispatch, 0);
+    else
+      this._timeoutId = null;
+
+    if (this._transport.onmessage)
+      this._transport.onmessage.call(null, message);
+  }
+}
+
--- a/Show More
+++ b/Show More