fix(network): make allHeaders wait until all header are available
Before, calling `allHeaders()` from `page.on('request')` would yield
provisional headers instead.
With these changes:
- In Firefox, all headers are available immediately.
- In Chromium, all headers are available upon requestWillBeSentExtraInfo.
- In WebKit, all headers are available upon responseReceived.
- In all browsers, intercepted requests use "provisional" headers
as all headers, since there is no network stack to change the headers.
Drive-by: migrated Chromium to `hasExtraInfo` flags that simplifies
the logic quite a bit.
Currently, `loadstate` and `load` are two separate events in the protocol,
and are fired in this order. As a result, `waitForLoadState()` sometimes
resolves before the `'load'` event is fired, which is unexpected.
Also fixes a flaky test that assumed `load` event comes after `domcontentloaded`
for the empty page, which is not always a case in Chromium.
- `har` option is now an object `{ path, fallback }`.
- Allows falling back to `abort()`, `continue()` or throwing.
- Matches based on url + method.
- Follows redirects in the HAR file.
- Nice error/stack when throwing.
- Tests.
Fixes focus and blur management when `page.locator(…).focus()` and `page.locator(…).type(…)` are used which was regressed by 7a5b070 (#13510).
#13510 relied on an implicit assumption that this (conditional) [`blur`](7a5b070e95/packages/playwright-core/src/server/injected/injectedScript.ts (L672)) call would always be followed by a call that resulted in a newly focused element via this [`focus`](7a5b070e95/packages/playwright-core/src/server/injected/injectedScript.ts (L674)) call.
However, some elements are [not focusable](https://html.spec.whatwg.org/multipage/interaction.html#focusable-area), so we were blurring incorrectly, and losing focus that we should have maintained.
Two regression tests were added that pass on the commit prior to 7a5b070e95 (and match manual testing/expectations):
* `page.locator(…).focus()`: _keeps focus on element when attempting to focus a non-focusable element_
* `page.locator(…).type(…)`: _should type repeatedly in input in shadow dom_
Additionally, a third test (_should type repeatedly in input in shadow dom_) was added to check the invariant from #13510 that states:
> This affects [contenteditable] elements, but not input elements.
and allows us to introduce the targeted fix (contenteditble check before blur) without breaking FF again.
And _should type repeatedly in contenteditable in shadow dom with nested elements_ was added to ensure the above fix works with nest contenteditble detection.
Fixes#14254.
