Gracefully handle a self-referential opener in frame swap.

third_party/WebKit/public/web/WebFrame.h

 /*
  * 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 689 matching lines @@
     explicit WebFrame(WebTreeScopeType);
     virtual ~WebFrame();
 
     // Sets the parent WITHOUT fulling adding it to the frame tree.
     // Used to lie to a local frame that is replacing a remote frame,
     // so it can properly start a navigation but wait to swap until
     // commit-time.
     void setParent(WebFrame*);
 
 private:
-    friend class OpenedFrameTracker;
-
 #if BLINK_IMPLEMENTATION
 #if ENABLE(OILPAN)
     static void traceFrame(Visitor*, WebFrame*);
     static void traceFrame(InlinedGlobalMarkingVisitor, WebFrame*);
     static bool isFrameAlive(const WebFrame*);
 
     template <typename VisitorDispatcher>
     static void traceFramesImpl(VisitorDispatcher, WebFrame*);
     template <typename VisitorDispatcher>
     void clearWeakFramesImpl(VisitorDispatcher);
@@ skipping 14 matching lines @@
     WebPrivateOwnPtr<OpenedFrameTracker> m_openedFrameTracker;
 };
 
 #if BLINK_IMPLEMENTATION
 Frame* toCoreFrame(const WebFrame*);
 #endif
 
 } // namespace blink
 
 #endif