Have window.closed return true when frame is closed.

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 480 matching lines @@
 WebRemoteFrame* WebLocalFrameImpl::toWebRemoteFrame()
 {
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 void WebLocalFrameImpl::close()
 {
     m_client = 0;
 
+    if (m_frame)
+        m_frame->setHasBeenClosed();
+
     deref(); // Balances ref() acquired in WebFrame::create
 }
 
 WebString WebLocalFrameImpl::uniqueName() const
 {
     return frame()->tree().uniqueName();
 }
 
 WebString WebLocalFrameImpl::assignedName() const
 {
@@ skipping 1359 matching lines @@
 
 void WebLocalFrameImpl::invalidateAll() const
 {
     ASSERT(frame() && frame()->view());
     FrameView* view = frame()->view();
     view->invalidateRect(view->frameRect());
     invalidateScrollbar();
 }
 
 } // namespace blink