Keep frames to navigate alive in HistoryController::goToEntry()

Source/core/page/HistoryController.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * 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.
@@ skipping 137 matching lines @@
 
     PassRefPtr<HistoryItem> currentItemForExport();
     PassRefPtr<HistoryItem> previousItemForExport();
     HistoryItem* itemForNewChildFrame(Frame*) const;
     void removeChildrenForRedirect(Frame*);
 
     void setDefersLoading(bool);
 
 private:
     void goToEntry(PassOwnPtr<HistoryEntry>, ResourceRequestCachePolicy);
-    typedef HashMap<Frame*, HistoryItem*> HistoryFrameLoadSet;
+    typedef HashMap<RefPtr<Frame>, HistoryItem*> HistoryFrameLoadSet;
     void recursiveGoToEntry(Frame*, HistoryFrameLoadSet& sameDocumentLoads, HistoryFrameLoadSet& differentDocumentLoads);
 
     void updateForInitialLoadInChildFrame(Frame*, HistoryItem*);
     void createNewBackForwardItem(Frame*, HistoryItem*, bool doClip);
 
     Page* m_page;
 
     OwnPtr<HistoryEntry> m_currentEntry;
     OwnPtr<HistoryEntry> m_previousEntry;
     OwnPtr<HistoryEntry> m_provisionalEntry;
 
     bool m_defersLoading;
     RefPtr<HistoryItem> m_deferredItem;
     ResourceRequestCachePolicy m_deferredCachePolicy;
 };
 
 } // namespace WebCore
 
 #endif // HistoryController_h