feat: Add --chromium-pref flag

package.json

@@ -63,7 +63,7 @@
     "addons-linter": "6.17.0",
     "bunyan": "1.8.15",
     "camelcase": "8.0.0",
-    "chrome-launcher": "0.15.1",
+    "chrome-launcher": "1.1.0",
     "debounce": "1.2.1",
     "decamelize": "6.0.0",
     "es6-error": "4.1.1",
@@ -82,6 +82,7 @@
     "open": "9.1.0",
     "parse-json": "7.1.1",
     "promise-toolbox": "0.21.0",
+    "set-value": "4.1.0",
     "source-map-support": "0.5.21",
     "strip-bom": "5.0.0",
     "strip-json-comments": "5.0.1",

src/cmd/run.js

@@ -49,6 +49,7 @@ export default async function run(
     firefoxApkComponent,
     // Chromium CLI options.
     chromiumBinary,
+    chromiumPref,
     chromiumProfile,
   },
   {
@@ -86,6 +87,10 @@ export default async function run(
     customPrefs['extensions.manifestV3.enabled'] = true;
   }
 
+  // Create an alias for --chromium-pref since it has been transformed into an
+  // object containing one or more preferences.
+  const customChromiumPrefs = { ...chromiumPref };
+
   const manifestData = await getValidatedManifest(sourceDir);
 
   const profileDir = firefoxProfile || chromiumProfile;
@@ -193,6 +198,7 @@ export default async function run(
       ...commonRunnerParams,
       chromiumBinary,
       chromiumProfile,
+      customChromiumPrefs,
     };
 
     const chromiumRunner = await createExtensionRunner({

src/extension-runners/chromium.js

@@ -12,6 +12,7 @@ import {
   launch as defaultChromiumLaunch,
 } from 'chrome-launcher';
 import WebSocket, { WebSocketServer } from 'ws';
+import set from 'set-value';
 
 import { createLogger } from '../util/logger.js';
 import { TempDir } from '../util/temp-dir.js';
@@ -26,6 +27,10 @@ export const DEFAULT_CHROME_FLAGS = ChromeLauncher.defaultFlags().filter(
   (flag) => !EXCLUDED_CHROME_FLAGS.includes(flag),
 );
 
+const DEFAULT_PREFS = {
+  'extensions.ui.developer_mode': true,
+};
+
 /**
  * Implements an IExtensionRunner which manages a Chromium instance.
  */
@@ -210,6 +215,7 @@ export class ChromiumExtensionRunner {
       userDataDir,
       // Ignore default flags to keep the extension enabled.
       ignoreDefaultFlags: true,
+      prefs: this.getPrefs(),
     });
 
     this.chromiumInstance.process.once('close', () => {
@@ -414,4 +420,18 @@ export class ChromiumExtensionRunner {
       }
     }
   }
+
+  /**
+   * Returns a deep preferences object based on a set of flat preferences, like
+   * "extensions.ui.developer_mode".
+   */
+  getPrefs() {
+    return Object.entries({
+      ...DEFAULT_PREFS,
+      ...(this.params.customChromiumPrefs || {}),
+    }).reduce((prefs, [key, value]) => {
+      set(prefs, key, value);
+      return prefs;
+    }, {});
+  }
 }

src/program.js

@@ -630,6 +630,18 @@ Example: $0 --help run.
         demandOption: false,
         type: 'string',
       },
+      'chromium-pref': {
+        describe:
+          'Launch chromium with a custom preference ' +
+          '(example: --chromium-pref=browser.theme.follows_system_colors=false). ' +
+          'You can repeat this option to set more than one ' +
+          'preference.',
+        demandOption: false,
+        requiresArg: true,
+        type: 'array',
+        coerce: (arg) =>
+          arg != null ? coerceCLICustomPreference(arg) : undefined,
+      },
       'chromium-profile': {
         describe: 'Path to a custom Chromium profile',
         demandOption: false,

tests/unit/test-extension-runners/test.chromium.js

@@ -49,7 +49,7 @@ describe('util/extension-runners/chromium', async () => {
   it('uses the expected chrome flags', () => {
     // Flags from chrome-launcher v0.14.0
     const expectedFlags = [
-      '--disable-features=Translate',
+      '--disable-features=Translate,OptimizationHints,MediaRouter,DialMediaRouteProvider,CalculateNativeWinOcclusion,InterestFeedContentSuggestions,CertificateTransparencyComponentUpdater,AutofillServerCommunication',
       '--disable-component-extensions-with-background-pages',
       '--disable-background-networking',
       '--disable-component-update',
@@ -66,6 +66,9 @@ describe('util/extension-runners/chromium', async () => {
       '--password-store=basic',
       '--use-mock-keychain',
       '--force-fieldtrials=*BackgroundTracing/default/',
+      '--disable-hang-monitor',
+      '--disable-prompt-on-repost',
+      '--disable-domain-reliability',
     ];
 
     assert.deepEqual(DEFAULT_CHROME_FLAGS, expectedFlags);
@@ -615,6 +618,56 @@ describe('util/extension-runners/chromium', async () => {
       }),
   );
 
+  it('does pass default prefs to chrome', async () => {
+    const { params } = prepareExtensionRunnerParams();
+
+    const runnerInstance = new ChromiumExtensionRunner(params);
+    await runnerInstance.run();
+
+    sinon.assert.calledOnce(params.chromiumLaunch);
+    sinon.assert.calledWithMatch(params.chromiumLaunch, {
+      prefs: {
+        extensions: {
+          ui: {
+            developer_mode: true,
+          },
+        },
+      },
+    });
+
+    await runnerInstance.exit();
+  });
+
+  it('does pass custom prefs to chrome', async () => {
+    const { params } = prepareExtensionRunnerParams({
+      params: {
+        customChromiumPrefs: {
+          'download.default_directory': '/some/directory',
+          'extensions.ui.developer_mode': false,
+        },
+      },
+    });
+
+    const runnerInstance = new ChromiumExtensionRunner(params);
+    await runnerInstance.run();
+
+    sinon.assert.calledOnce(params.chromiumLaunch);
+    sinon.assert.calledWithMatch(params.chromiumLaunch, {
+      prefs: {
+        download: {
+          default_directory: '/some/directory',
+        },
+        extensions: {
+          ui: {
+            developer_mode: false,
+          },
+        },
+      },
+    });
+
+    await runnerInstance.exit();
+  });
+
   describe('reloadAllExtensions', () => {
     let runnerInstance;
     let wsClient;

tests/unit/test.program.js

@@ -627,6 +627,27 @@ describe('program.main', () => {
     });
   });
 
+  it('converts custom chromium preferences into an object', () => {
+    const fakeCommands = fake(commands, {
+      run: () => Promise.resolve(),
+    });
+    return execProgram(
+      [
+        'run',
+        '--chromium-pref',
+        'prop=true',
+        '--chromium-pref',
+        'prop2=value2',
+      ],
+      { commands: fakeCommands },
+    ).then(() => {
+      const { chromiumPref } = fakeCommands.run.firstCall.args[0];
+      assert.isObject(chromiumPref);
+      assert.equal(chromiumPref.prop, true);
+      assert.equal(chromiumPref.prop2, 'value2');
+    });
+  });
+
   it('passes shouldExitProgram option to commands', () => {
     const fakeCommands = fake(commands, {
       lint: () => Promise.resolve(),