Oilpan: move MHTML objects to the heap.

Source/core/loader/DocumentLoader.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 191 matching lines @@
         bool m_committed;
         bool m_isClientRedirect;
         bool m_replacesCurrentHistoryItem;
 
         AtomicString m_overrideEncoding;
 
         // The action that triggered loading - we keep this around for the
         // benefit of the various policy handlers.
         NavigationAction m_triggeringAction;
 
-        OwnPtr<ArchiveResourceCollection> m_archiveResourceCollection;
-        RefPtr<MHTMLArchive> m_archive;
+        OwnPtrWillBePersistent<ArchiveResourceCollection> m_archiveResourceCollection;
+        RefPtrWillBePersistent<MHTMLArchive> m_archive;
 
         bool m_loadingMainResource;
         DocumentLoadTiming m_documentLoadTiming;
 
         double m_timeOfLastDataReceived;
 
         friend class ApplicationCacheHost;  // for substitute resource delivery
         OwnPtr<ApplicationCacheHost> m_applicationCacheHost;
     };
 }
 
 #endif // DocumentLoader_h