Add [WillBeGarbageCollected] to Event.idl

Source/modules/mediastream/MediaStreamTrackEvent.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 18 matching lines @@
 #include "wtf/text/AtomicString.h"
 
 namespace WebCore {
 
 class MediaStreamTrack;
 
 class MediaStreamTrackEvent FINAL : public Event {
 public:
     virtual ~MediaStreamTrackEvent();
 
-    static PassRefPtr<MediaStreamTrackEvent> create();
-    static PassRefPtr<MediaStreamTrackEvent> create(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<MediaStreamTrack>);
+    static PassRefPtrWillBeRawPtr<MediaStreamTrackEvent> create();
+    static PassRefPtrWillBeRawPtr<MediaStreamTrackEvent> create(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<MediaStreamTrack>);
 
     MediaStreamTrack* track() const;
 
     // Event
     virtual const AtomicString& interfaceName() const OVERRIDE;
 
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     MediaStreamTrackEvent();
     MediaStreamTrackEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<MediaStreamTrack>);
 
     RefPtr<MediaStreamTrack> m_track;
 };
 
 } // namespace WebCore
 
 #endif // MediaStreamTrackEvent_h