Add [WillBeGarbageCollected] to Event.idl

Source/core/events/ClipboardEvent.h

Index: Source/core/events/ClipboardEvent.h
diff --git a/Source/core/events/ClipboardEvent.h b/Source/core/events/ClipboardEvent.h
index 66ae9c8e773fa96cd58673d4df201df8bfee0ef1..d32db9f02acc17808ed694b469cbd471876a1811 100644
--- a/Source/core/events/ClipboardEvent.h
+++ b/Source/core/events/ClipboardEvent.h
@@ -34,9 +34,9 @@ namespace WebCore {
     public:
         virtual ~ClipboardEvent();
 
-        static PassRefPtr<ClipboardEvent> create(const AtomicString& type, bool canBubbleArg, bool cancelableArg, PassRefPtrWillBeRawPtr<Clipboard> clipboardArg)
+        static PassRefPtrWillBeRawPtr<ClipboardEvent> create(const AtomicString& type, bool canBubbleArg, bool cancelableArg, PassRefPtrWillBeRawPtr<Clipboard> clipboardArg)
         {
-            return adoptRef(new ClipboardEvent(type, canBubbleArg, cancelableArg, clipboardArg));
+            return adoptRefWillBeRefCountedGarbageCollected(new ClipboardEvent(type, canBubbleArg, cancelableArg, clipboardArg));
         }
 
         Clipboard* clipboard() const { return m_clipboard.get(); }