Call LocalDOMWindow::clearDocument when a frame gets detached

third_party/WebKit/Source/bindings/core/v8/BindingSecurity.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 197 matching lines @@
                         target->domWindow(), reportingOption);
 }
 
 bool BindingSecurity::shouldAllowAccessToDetachedWindow(
     const LocalDOMWindow* accessingWindow,
     const DOMWindow* target,
     ExceptionState& exceptionState) {
   CHECK(target && !target->frame())
       << "This version of shouldAllowAccessToFrame() must be used only for "
       << "detached windows.";
-  if (!target->document())
-    return false;
+  CHECK(target->document());
   return canAccessFrame(accessingWindow,
                         target->document()->getSecurityOrigin(), target,
                         exceptionState);
 }
 
 }  // namespace blink