Have window.closed return true when frame is closed.

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 1177 matching lines @@
     if (!view)
         return 0;
 
     m_frame->document()->updateLayoutIgnorePendingStylesheets();
 
     return adjustForAbsoluteZoom(view->scrollY(), m_frame->pageZoomFactor());
 }
 
 bool LocalDOMWindow::closed() const
 {
-    return !m_frame;
+    return !m_frame || m_frame->hasBeenClosed();
 }
 
 unsigned LocalDOMWindow::length() const
 {
     if (!isCurrentlyDisplayedInFrame())
         return 0;
 
     return m_frame->tree().scopedChildCount();
 }
 
@@ skipping 705 matching lines @@
     LifecycleContext<LocalDOMWindow>::trace(visitor);
 }
 
 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