Revert of Keep track in the browser of which frames have onunload and onbeforeunload handlers.

third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 237 matching lines @@
   DOMWindowSet::iterator it = set.Find(dom_window);
   if (it == set.end())
     return;
   set.RemoveAll(it);
   if (set.IsEmpty()) {
     UpdateSuddenTerminationStatus(dom_window, false,
                                   LocalFrameClient::kBeforeUnloadHandler);
   }
 }
 
+static bool AllowsBeforeUnloadListeners(LocalDOMWindow* window) {
+  DCHECK(window);
+  LocalFrame* frame = window->GetFrame();
+  if (!frame)
+    return false;
+  return frame->IsMainFrame();
+}
+
 unsigned LocalDOMWindow::PendingUnloadEventListeners() const {
   return WindowsWithUnloadEventListeners().Count(
       const_cast<LocalDOMWindow*>(this));
 }
 
 bool LocalDOMWindow::AllowPopUp(LocalFrame& first_frame) {
   if (UserGestureIndicator::UtilizeUserGesture())
     return true;
 
   Settings* settings = first_frame.GetSettings();
@@ skipping 1165 matching lines @@
 
   for (auto& it : event_listener_observers_) {
     it->DidAddEventListener(this, event_type);
   }
 
   if (event_type == EventTypeNames::unload) {
     UseCounter::Count(document(), UseCounter::kDocumentUnloadRegistered);
     AddUnloadEventListener(this);
   } else if (event_type == EventTypeNames::beforeunload) {
     UseCounter::Count(document(), UseCounter::kDocumentBeforeUnloadRegistered);
-    AddBeforeUnloadEventListener(this);
-    if (GetFrame() && !GetFrame()->IsMainFrame())
+    if (AllowsBeforeUnloadListeners(this)) {
+      // This is confusingly named. It doesn't actually add the listener. It
+      // just increments a count so that we know we have listeners registered
+      // for the purposes of determining if we can fast terminate the renderer
+      // process.
+      AddBeforeUnloadEventListener(this);
+    } else {
+      // Subframes return false from allowsBeforeUnloadListeners.
       UseCounter::Count(document(),
                         UseCounter::kSubFrameBeforeUnloadRegistered);
+    }
   }
 }
 
 void LocalDOMWindow::RemovedEventListener(
     const AtomicString& event_type,
     const RegisteredEventListener& registered_listener) {
   DOMWindow::RemovedEventListener(event_type, registered_listener);
   if (GetFrame() && GetFrame()->GetPage())
     GetFrame()->GetPage()->GetEventHandlerRegistry().DidRemoveEventHandler(
         *this, event_type, registered_listener.Options());
 
   for (auto& it : event_listener_observers_) {
     it->DidRemoveEventListener(this, event_type);
   }
 
   if (event_type == EventTypeNames::unload) {
     RemoveUnloadEventListener(this);
-  } else if (event_type == EventTypeNames::beforeunload) {
+  } else if (event_type == EventTypeNames::beforeunload &&
+             AllowsBeforeUnloadListeners(this)) {
     RemoveBeforeUnloadEventListener(this);
   }
 }
 
 void LocalDOMWindow::WarnUnusedPreloads(TimerBase* base) {
   if (GetFrame() && GetFrame()->Loader().GetDocumentLoader()) {
     ResourceFetcher* fetcher =
         GetFrame()->Loader().GetDocumentLoader()->Fetcher();
     DCHECK(fetcher);
     if (fetcher->CountPreloads())
@@ skipping 188 matching lines @@
   DOMWindow::Trace(visitor);
   Supplementable<LocalDOMWindow>::Trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(LocalDOMWindow) {
   visitor->TraceWrappers(custom_elements_);
   DOMWindow::TraceWrappers(visitor);
 }
 
 }  // namespace blink