Add [WillBeGarbageCollected] to Event.idl

Source/modules/mediastream/RTCDTMFToneChangeEvent.h

 /*
  * Copyright (C) 2013 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 RTCDTMFToneChangeEventInit : public EventInit {
     String tone;
 };
 
 class RTCDTMFToneChangeEvent FINAL : public Event {
 public:
     virtual ~RTCDTMFToneChangeEvent();
 
-    static PassRefPtr<RTCDTMFToneChangeEvent> create();
-    static PassRefPtr<RTCDTMFToneChangeEvent> create(const String& tone);
-    static PassRefPtr<RTCDTMFToneChangeEvent> create(const AtomicString& type, const RTCDTMFToneChangeEventInit& initializer);
+    static PassRefPtrWillBeRawPtr<RTCDTMFToneChangeEvent> create();
+    static PassRefPtrWillBeRawPtr<RTCDTMFToneChangeEvent> create(const String& tone);
+    static PassRefPtrWillBeRawPtr<RTCDTMFToneChangeEvent> create(const AtomicString& type, const RTCDTMFToneChangeEventInit& initializer);
 
     const String& tone() const;
 
     virtual const AtomicString& interfaceName() const OVERRIDE;
 
     virtual void trace(Visitor*) OVERRIDE;
 
 private:
     RTCDTMFToneChangeEvent();
     explicit RTCDTMFToneChangeEvent(const String& tone);
     explicit RTCDTMFToneChangeEvent(const RTCDTMFToneChangeEventInit&);
 
     String m_tone;
 };
 
 } // namespace WebCore
 
 #endif // RTCDTMFToneChangeEvent_h