Add [WillBeGarbageCollected] to Event.idl

Source/core/html/MediaKeyEvent.h

Index: Source/core/html/MediaKeyEvent.h
diff --git a/Source/core/html/MediaKeyEvent.h b/Source/core/html/MediaKeyEvent.h
index fb7112743a813613525fb369eeda0a2f71855faa..4e5ce4c58ac31c3eba158de97635e6d3fe9a1bbb 100644
--- a/Source/core/html/MediaKeyEvent.h
+++ b/Source/core/html/MediaKeyEvent.h
@@ -47,14 +47,14 @@ class MediaKeyEvent FINAL : public Event {
 public:
     virtual ~MediaKeyEvent();
 
-    static PassRefPtr<MediaKeyEvent> create()
+    static PassRefPtrWillBeRawPtr<MediaKeyEvent> create()
     {
-        return adoptRef(new MediaKeyEvent);
+        return adoptRefWillBeRefCountedGarbageCollected(new MediaKeyEvent);
     }
 
-    static PassRefPtr<MediaKeyEvent> create(const AtomicString& type, const MediaKeyEventInit& initializer)
+    static PassRefPtrWillBeRawPtr<MediaKeyEvent> create(const AtomicString& type, const MediaKeyEventInit& initializer)
     {
-        return adoptRef(new MediaKeyEvent(type, initializer));
+        return adoptRefWillBeRefCountedGarbageCollected(new MediaKeyEvent(type, initializer));
     }
 
     virtual const AtomicString& interfaceName() const OVERRIDE;