fix(events): avoid firing events after close/detach (#2919)

src/frames.ts

@@ -71,6 +71,11 @@ export class FrameManager {
     this._mainFrame = undefined as any as Frame;
   }
 
+  dispose() {
+    for (const frame of this._frames.values())
+      frame._stopNetworkIdleTimer();
+  }
+
   mainFrame(): Frame {
     return this._mainFrame;
   }
@@ -926,6 +931,7 @@ export class Frame {
   }
 
   _onDetached() {
+    this._stopNetworkIdleTimer();
     this._detached = true;
     this._detachedCallback();
     for (const data of this._contextData.values()) {

src/page.ts

@@ -145,6 +145,7 @@ export class Page extends EventEmitter {
   }
 
   _didClose() {
+    this._frameManager.dispose();
     assert(this._closedState !== 'closed', 'Page closed twice');
     this._closedState = 'closed';
     this.emit(Events.Page.Close);
@@ -152,11 +153,13 @@ export class Page extends EventEmitter {
   }
 
   _didCrash() {
+    this._frameManager.dispose();
     this.emit(Events.Page.Crash);
     this._crashedCallback(new Error('Page crashed'));
   }
 
   _didDisconnect() {
+    this._frameManager.dispose();
     assert(!this._disconnected, 'Page disconnected twice');
     this._disconnected = true;
     this._disconnectedCallback(new Error('Page closed'));