chromium module: add support for chromium policies as nixos module

nixos/modules/module-list.nix

@@ -66,6 +66,7 @@
   ./programs/bash/bash.nix
   ./programs/blcr.nix
   ./programs/cdemu.nix
+  ./programs/chromium.nix
   ./programs/command-not-found/command-not-found.nix
   ./programs/dconf.nix
   ./programs/environment.nix

nixos/modules/programs/chromium.nix

@@ -0,0 +1,85 @@
+{ config, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.chromium;
+
+  defaultProfile = filterAttrs (k: v: v != null) {
+    HomepageLocation = cfg.homepageLocation;
+    DefaultSearchProviderSearchURL = cfg.defaultSearchProviderSearchURL;
+    DefaultSearchProviderSuggestURL = cfg.defaultSearchProviderSuggestURL;
+    ExtensionInstallForcelist = map (extension:
+      "${extension};https://clients2.google.com/service/update2/crx"
+    ) cfg.extensions;
+  };
+in
+
+{
+  ###### interface
+
+  options = {
+    programs.chromium = {
+      enable = mkEnableOption "<command>chromium</command> policies";
+
+      extensions = mkOption {
+        type = types.listOf types.str;
+        description = ''
+          List of chromium extensions to install.
+          For list of plugins ids see id in url of extensions on
+          <link xlink:href="https://chrome.google.com/webstore/category/extensions">chrome web store</link>
+          page.
+        '';
+        default = [];
+        example = literalExample ''
+          [
+            "chlffgpmiacpedhhbkiomidkjlcfhogd" # pushbullet
+            "mbniclmhobmnbdlbpiphghaielnnpgdp" # lightshot
+            "gcbommkclmclpchllfjekcdonpmejbdp" # https everywhere
+          ]
+        '';
+      };
+
+      homepageLocation = mkOption {
+        type = types.nullOr types.str;
+        description = "Chromium default homepage";
+        default = null;
+        example = "https://nixos.org";
+      };
+
+      defaultSearchProviderSearchURL = mkOption {
+        type = types.nullOr types.str;
+        description = "Chromium default search provider url.";
+        default = null;
+        example =
+          "https://encrypted.google.com/search?q={searchTerms}&{google:RLZ}{google:originalQueryForSuggestion}{google:assistedQueryStats}{google:searchFieldtrialParameter}{google:
+        ↪searchClient}{google:sourceId}{google:instantExtendedEnabledParameter}ie={inputEncoding}";
+      };
+
+      defaultSearchProviderSuggestURL = mkOption {
+        type = types.nullOr types.str;
+        description = "Chromium default search provider url for suggestions.";
+        default = null;
+        example =
+          "https://encrypted.google.com/complete/search?output=chrome&q={searchTerms}";
+      };
+
+      extraOpts = mkOption {
+        type = types.attrs;
+        description = ''
+          Extra chromium policy options, see
+          <link xlink:href="https://www.chromium.org/administrators/policy-list-3">https://www.chromium.org/administrators/policy-list-3</link>
+          for a list of avalible options
+        '';
+        default = {};
+      };
+    };
+  };
+
+  ###### implementation
+
+  config = lib.mkIf cfg.enable {
+    environment.etc."chromium/policies/managed/default.json".text = builtins.toJSON defaultProfile;
+    environment.etc."chromium/policies/managed/extra.json".text = builtins.toJSON cfg.extraOpts;
+  };
+}