fix(test-runner-chrome): remove focus browser patches

The patches were added quite a while ago, and the upstream issues should
be resolved in Chromium. See: https://issues.chromium.org/issues/40272146.

Also see:
puppeteer/puppeteer#10350 (comment).

The patches are currently also resulting some instability of web test
runner. That is because the patch calls an exposed function from inside
the browser, while navigation later on during `stopSession` can happen;
breaking the handle for retrieving function call arguments passed to the
exposed function.

Puppeteer team found this issue and also landed a fix to improve the
failure mode here. See:
puppeteer/puppeteer#13759

Author: devversion

.changeset/kind-schools-rule.md

@@ -0,0 +1,22 @@
+---
+'@web/test-runner-chrome': patch
+---
+
+This changeset removes the Puppeteer/Chrome focus browser patches that shouldn't
+be needed anymore, and can cause instability.
+
+The patches were added quite a while ago, and the upstream issues should
+be resolved in Chromium. See: https://issues.chromium.org/issues/40272146.
+
+Also see:
+https://github.com/puppeteer/puppeteer/issues/10350#issuecomment-1586858101.
+
+The patches are currently also resulting some instability of web test
+runner. That is because the patch calls an exposed function from inside
+the browser, while navigation later on during `stopSession` can happen;
+breaking the handle for retrieving function call arguments passed to the
+exposed function.
+
+Puppeteer team found this issue and also landed a fix to improve the
+failure mode here. See:
+https://github.com/puppeteer/puppeteer/pull/13759

package-lock.json

@@ -48,7 +48,6 @@
   "dependencies": {
     "@web/test-runner-core": "^0.13.0",
     "@web/test-runner-coverage-v8": "^0.8.0",
-    "async-mutex": "0.4.0",
     "chrome-launcher": "^0.15.0",
     "puppeteer-core": "^24.0.0"
   },

packages/test-runner-chrome/package.json

@@ -2,9 +2,6 @@ import { Page, JSCoverageEntry } from 'puppeteer-core';
 import { TestRunnerCoreConfig } from '@web/test-runner-core';
 import { v8ToIstanbul } from '@web/test-runner-coverage-v8';
 import { SessionResult } from '@web/test-runner-core';
-import { Mutex } from 'async-mutex';
-
-const mutex = new Mutex();
 
 declare global {
   interface Window {
@@ -49,43 +46,6 @@ export class ChromeLauncherPage {
       });
     }
 
-    // Patching the browser page to workaround an issue in the new headless mode of Chrome where some functions
-    // with callbacks (requestAnimationFrame and requestIdleCallback) are not executing their callbacks.
-    // https://github.com/puppeteer/puppeteer/issues/10350
-    if (!this.patchAdded) {
-      await this.puppeteerPage.exposeFunction('__bringTabToFront', (id: string) => {
-        const promise = new Promise(resolve => {
-          this.resolvers[id] = resolve as () => void;
-        });
-        return mutex.runExclusive(async () => {
-          await this.puppeteerPage.bringToFront();
-          await promise;
-        });
-      });
-      await this.puppeteerPage.exposeFunction('__releaseLock', (id: string) => {
-        this.resolvers[id]?.();
-      });
-      await this.puppeteerPage.evaluateOnNewDocument(() => {
-        // eslint-disable-next-line @typescript-eslint/ban-types
-        function patchFunction(name: string, fn: Function) {
-          (window as any)[name] = (...args: unknown[]) => {
-            const result = fn.call(window, ...args);
-            const id = Math.random().toString().substring(2);
-            // Make sure that the tab running the test code is brought back to the front.
-            window.__bringTabToFront(id);
-            fn.call(window, () => {
-              window.__releaseLock(id);
-            });
-            return result;
-          };
-        }
-
-        patchFunction('requestAnimationFrame', window.requestAnimationFrame);
-        patchFunction('requestIdleCallback', window.requestIdleCallback);
-      });
-      this.patchAdded = true;
-    }
-
     await this.puppeteerPage.setViewport({ height: 600, width: 800 });
     await this.puppeteerPage.goto(url);
   }