Oilpan: move MediaKeyError to the heap.

Source/modules/encryptedmedia/MediaKeySession.h

 /*
  * Copyright (C) 2013 Apple 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 105 matching lines @@
     void actionTimerFired(Timer<MediaKeySession>*);
 
     // blink::WebContentDecryptionModuleSession::Client
     virtual void message(const unsigned char* message, size_t messageLength, const blink::WebURL& destinationURL) OVERRIDE;
     virtual void ready() OVERRIDE;
     virtual void close() OVERRIDE;
     virtual void error(MediaKeyErrorCode, unsigned long systemCode) OVERRIDE;
     virtual void error(blink::WebContentDecryptionModuleException, unsigned long systemCode, const blink::WebString& errorMessage) OVERRIDE;
 
     String m_keySystem;
-    RefPtr<MediaKeyError> m_error;
+    RefPtrWillBeMember<MediaKeyError> m_error;
     OwnPtrWillBeMember<GenericEventQueue> m_asyncEventQueue;
     OwnPtr<blink::WebContentDecryptionModuleSession> m_session;
 
     // Used to determine if MediaKeys is still active.
     WeakMember<MediaKeys> m_keys;
 
     // Is the CDM finished with this session?
     bool m_isClosed;
 
     Deque<OwnPtr<PendingAction> > m_pendingActions;
     Timer<MediaKeySession> m_actionTimer;
 };
 
 }
 
 #endif // MediaKeySession_h