Inform the WebFrameClient of BeforeUnload/Unload handlers

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 213 matching lines @@
     DEFINE_STATIC_LOCAL(DOMWindowSet, windowsWithBeforeUnloadEventListeners, ());
     return windowsWithBeforeUnloadEventListeners;
 }
 
 static void addUnloadEventListener(LocalDOMWindow* domWindow)
 {
     DOMWindowSet& set = windowsWithUnloadEventListeners();
     if (set.isEmpty())
         disableSuddenTermination();
     set.add(domWindow);
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        1, FrameLoaderClient::UnloadHandler);
 }
 
 static void removeUnloadEventListener(LocalDOMWindow* domWindow)
 {
     DOMWindowSet& set = windowsWithUnloadEventListeners();
     DOMWindowSet::iterator it = set.find(domWindow);
     if (it == set.end())
         return;
     set.remove(it);
     if (set.isEmpty())
         enableSuddenTermination();

[Nate Chapin, 2015/01/20 18:46:49]

Will we eventually be able to remove these enable/disable calls?

[clamy, 2015/01/21 13:46:31]

Yes, when the chromium side patch lands we should remove those. However we
cannot get completely rid of blink::Platform::suddenTerminationChanged, because
we cannot track per-Frame the disables of sudden termination caused by pending
DOM local storage callbacks. It seems it has to be done per-process.

[Nate Chapin, 2015/01/21 19:51:42]

Interesting, I would have thought that local storage could be per-frame as well,
but I know nothing about the chromium-side implementation.

+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(

[Nate Chapin, 2015/01/20 18:46:49]

Is this safe? domWindow->frame() can be null at very annoying times.

[clamy, 2015/01/21 13:46:31]

In that case I added a check for domWindow->frame() before calling
suddenTerminationDisablerChanged. It did not seem to cause bot failures without
it though.

[Nate Chapin, 2015/01/21 19:51:42]

I did a quick look and didn't see anything that would prevent an attempt to add
an event listener to a detached window, but it may be difficult to get into that
situation in practice. I would not be at all surprised if we don't have test
coverage for it.

If you are willing to tolerate the risk of a fire drill, you could omit the
null-checks and be prepared to deal with a potential crash report in a couple
days. I'd lean toward including the null-checks just to be safe, though.

+        -1, FrameLoaderClient::UnloadHandler);
 }
 
 static void removeAllUnloadEventListeners(LocalDOMWindow* domWindow)
 {
     DOMWindowSet& set = windowsWithUnloadEventListeners();
     DOMWindowSet::iterator it = set.find(domWindow);
     if (it == set.end())
         return;
+    int numHandlers = set.count(domWindow);
     set.removeAll(it);
     if (set.isEmpty())
         enableSuddenTermination();
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        -numHandlers, FrameLoaderClient::UnloadHandler);
 }
 
 static void addBeforeUnloadEventListener(LocalDOMWindow* domWindow)
 {
     DOMWindowSet& set = windowsWithBeforeUnloadEventListeners();
     if (set.isEmpty())
         disableSuddenTermination();
     set.add(domWindow);
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        1, FrameLoaderClient::BeforeUnloadHandler);
 }
 
 static void removeBeforeUnloadEventListener(LocalDOMWindow* domWindow)
 {
     DOMWindowSet& set = windowsWithBeforeUnloadEventListeners();
     DOMWindowSet::iterator it = set.find(domWindow);
     if (it == set.end())
         return;
     set.remove(it);
     if (set.isEmpty())
         enableSuddenTermination();
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        -1, FrameLoaderClient::BeforeUnloadHandler);
 }
 
 static void removeAllBeforeUnloadEventListeners(LocalDOMWindow* domWindow)
 {
     DOMWindowSet& set = windowsWithBeforeUnloadEventListeners();
     DOMWindowSet::iterator it = set.find(domWindow);
     if (it == set.end())
         return;
+    int numHandlers = set.count(domWindow);
     set.removeAll(it);
     if (set.isEmpty())
         enableSuddenTermination();
+    domWindow->frame()->loader().client()->suddenTerminationDisablerChanged(
+        -numHandlers, FrameLoaderClient::BeforeUnloadHandler);
 }
 
 static bool allowsBeforeUnloadListeners(LocalDOMWindow* window)
 {
     ASSERT_ARG(window, window);
     LocalFrame* frame = window->frame();
     if (!frame)
         return false;
     return frame->isMainFrame();
 }
@@ skipping 1619 matching lines @@
     return m_frameObserver->frame();
 }
 
 v8::Handle<v8::Object> LocalDOMWindow::wrap(v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
 {
     ASSERT_NOT_REACHED(); // LocalDOMWindow has [Custom=ToV8].
     return v8::Handle<v8::Object>();
 }
 
 } // namespace blink