Fire visibilityChange event on out-of-process iframes.

third_party/WebKit/Source/web/WebLocalFrameImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1799 matching lines @@
     toRemoteFrameOwner(owner)->setMarginWidth(frameOwnerProperties.marginWidth);
     toRemoteFrameOwner(owner)->setMarginHeight(frameOwnerProperties.marginHeight);
 }
 
 WebLocalFrameImpl* WebLocalFrameImpl::localRoot()
 {
     // This can't use the LocalFrame::localFrameRoot, since it may be called
     // when the WebLocalFrame exists but the core LocalFrame does not.
     // TODO(alexmos, dcheng): Clean this up to only calculate this in one place.
     WebLocalFrameImpl* localRoot = this;
-    while (!localRoot->frameWidget())
+    while (localRoot->parent() && localRoot->parent()->isWebLocalFrame())

[dcheng, 2016/05/24 20:38:24]

Why do we have to change this line?

[lfg, 2016/05/24 23:33:51]

After the renderer receives a ViewMsg_Close, the WebFrameWidget is deleted and
this method starts crashing.

         localRoot = toWebLocalFrameImpl(localRoot->parent());
     return localRoot;
 }
 
 WebLocalFrame* WebLocalFrameImpl::traversePreviousLocal(bool wrap) const
 {
     WebFrame* previousLocalFrame = this->traversePrevious(wrap);
     while (previousLocalFrame && !previousLocalFrame->isWebLocalFrame())
         previousLocalFrame = previousLocalFrame->traversePrevious(wrap);
     return previousLocalFrame ? previousLocalFrame->toWebLocalFrame() : nullptr;
@@ skipping 275 matching lines @@
         return WebSandboxFlags::None;
     return static_cast<WebSandboxFlags>(frame()->loader().effectiveSandboxFlags());
 }
 
 void WebLocalFrameImpl::forceSandboxFlags(WebSandboxFlags flags)
 {
     frame()->loader().forceSandboxFlags(static_cast<SandboxFlags>(flags));
 }
 
 } // namespace blink