Oilpan: move MediaKeyError to the heap.

Source/core/html/MediaKeyEvent.h

 /*
  * Copyright (C) 2012 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 21 matching lines @@
 namespace WebCore {
 
 struct MediaKeyEventInit : public EventInit {
     MediaKeyEventInit();
 
     String keySystem;
     String sessionId;
     RefPtr<Uint8Array> initData;
     RefPtr<Uint8Array> message;
     String defaultURL;
-    RefPtr<MediaKeyError> errorCode;
+    RefPtrWillBeMember<MediaKeyError> errorCode;
     unsigned short systemCode;
 };
 
 class MediaKeyEvent FINAL : public Event {
 public:
     virtual ~MediaKeyEvent();
 
     static PassRefPtrWillBeRawPtr<MediaKeyEvent> create()
     {
         return adoptRefWillBeNoop(new MediaKeyEvent);
@@ skipping 19 matching lines @@
 
 private:
     MediaKeyEvent();
     MediaKeyEvent(const AtomicString& type, const MediaKeyEventInit& initializer);
 
     String m_keySystem;
     String m_sessionId;
     RefPtr<Uint8Array> m_initData;
     RefPtr<Uint8Array> m_message;
     String m_defaultURL;
-    RefPtr<MediaKeyError> m_errorCode;
+    RefPtrWillBeMember<MediaKeyError> m_errorCode;
     unsigned short m_systemCode;
 };
 
 } // namespace WebCore
 
 #endif