4 files changed, 123 insertions, 1 deletions
diff --git a/remote/test/puppeteer/packages/puppeteer-core/src/util/Deferred.ts b/remote/test/puppeteer/packages/puppeteer-core/src/util/Deferred.ts
index 0dfb013bb3..6699ace36d 100644
--- a/remote/test/puppeteer/packages/puppeteer-core/src/util/Deferred.ts
+++ b/remote/test/puppeteer/packages/puppeteer-core/src/util/Deferred.ts
@@ -1,3 +1,8 @@
+/**
+ * @license
+ * Copyright 2024 Google Inc.
+ * SPDX-License-Identifier: Apache-2.0
+ */
 import {TimeoutError} from '../common/Errors.js';
 
 /**
diff --git a/remote/test/puppeteer/packages/puppeteer-core/src/util/Mutex.ts b/remote/test/puppeteer/packages/puppeteer-core/src/util/Mutex.ts
index 9498bac306..f789837def 100644
--- a/remote/test/puppeteer/packages/puppeteer-core/src/util/Mutex.ts
+++ b/remote/test/puppeteer/packages/puppeteer-core/src/util/Mutex.ts
@@ -1,3 +1,8 @@
+/**
+ * @license
+ * Copyright 2024 Google Inc.
+ * SPDX-License-Identifier: Apache-2.0
+ */
 import {Deferred} from './Deferred.js';
 import {disposeSymbol} from './disposable.js';
 
diff --git a/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.test.ts b/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.test.ts
index 4cdaf15d5b..bc476b0153 100644
--- a/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.test.ts
+++ b/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.test.ts
@@ -9,7 +9,9 @@ import {describe, it} from 'node:test';
 import expect from 'expect';
 import sinon from 'sinon';
 
-import {invokeAtMostOnceForArguments} from './decorators.js';
+import {EventEmitter} from '../common/EventEmitter.js';
+
+import {bubble, invokeAtMostOnceForArguments} from './decorators.js';
 
 describe('decorators', function () {
   describe('invokeAtMostOnceForArguments', () => {
@@ -76,4 +78,48 @@ describe('decorators', function () {
       }).toThrow();
     });
   });
+
+  describe('bubble', () => {
+    it('should work', () => {
+      class Test extends EventEmitter<any> {
+        @bubble()
+        accessor field = new EventEmitter();
+      }
+
+      const t = new Test();
+      let a = false;
+      t.on('a', (value: boolean) => {
+        a = value;
+      });
+
+      t.field.emit('a', true);
+      expect(a).toBeTruthy();
+
+      // Set a new emitter.
+      t.field = new EventEmitter();
+      a = false;
+
+      t.field.emit('a', true);
+      expect(a).toBeTruthy();
+    });
+
+    it('should not bubble down', () => {
+      class Test extends EventEmitter<any> {
+        @bubble()
+        accessor field = new EventEmitter<any>();
+      }
+
+      const t = new Test();
+      let a = false;
+      t.field.on('a', (value: boolean) => {
+        a = value;
+      });
+
+      t.emit('a', true);
+      expect(a).toBeFalsy();
+
+      t.field.emit('a', true);
+      expect(a).toBeTruthy();
+    });
+  });
 });
diff --git a/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.ts b/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.ts
index af21c5fe29..c4dc3b6c0d 100644
--- a/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.ts
+++ b/remote/test/puppeteer/packages/puppeteer-core/src/util/decorators.ts
@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import type {EventType} from '../common/EventEmitter.js';
+import type {EventEmitter} from '../common/EventEmitter.js';
 import type {Disposed, Moveable} from '../common/types.js';
 
 import {asyncDisposeSymbol, disposeSymbol} from './disposable.js';
@@ -138,3 +140,67 @@ export function guarded<T extends object>(
     };
   };
 }
+
+const bubbleHandlers = new WeakMap<object, Map<any, any>>();
+
+/**
+ * Event emitter fields marked with `bubble` will have their events bubble up
+ * the field owner.
+ */
+// The type is too complicated to type.
+// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+export function bubble<T extends EventType[]>(events?: T) {
+  return <This extends EventEmitter<any>, Value extends EventEmitter<any>>(
+    {set, get}: ClassAccessorDecoratorTarget<This, Value>,
+    context: ClassAccessorDecoratorContext<This, Value>
+  ): ClassAccessorDecoratorResult<This, Value> => {
+    context.addInitializer(function () {
+      const handlers = bubbleHandlers.get(this) ?? new Map();
+      if (handlers.has(events)) {
+        return;
+      }
+
+      const handler =
+        events !== undefined
+          ? (type: EventType, event: unknown) => {
+              if (events.includes(type)) {
+                this.emit(type, event);
+              }
+            }
+          : (type: EventType, event: unknown) => {
+              this.emit(type, event);
+            };
+
+      handlers.set(events, handler);
+      bubbleHandlers.set(this, handlers);
+    });
+    return {
+      set(emitter) {
+        const handler = bubbleHandlers.get(this)!.get(events)!;
+
+        // In case we are re-setting.
+        const oldEmitter = get.call(this);
+        if (oldEmitter !== undefined) {
+          oldEmitter.off('*', handler);
+        }
+
+        if (emitter === undefined) {
+          return;
+        }
+        emitter.on('*', handler);
+        set.call(this, emitter);
+      },
+      // @ts-expect-error -- TypeScript incorrectly types init to require a
+      // return.
+      init(emitter) {
+        if (emitter === undefined) {
+          return;
+        }
+        const handler = bubbleHandlers.get(this)!.get(events)!;
+
+        emitter.on('*', handler);
+        return emitter;
+      },
+    };
+  };
+}