Add [WillBeGarbageCollected] to Event.idl

Source/core/svg/SVGZoomEvent.h

Index: Source/core/svg/SVGZoomEvent.h
diff --git a/Source/core/svg/SVGZoomEvent.h b/Source/core/svg/SVGZoomEvent.h
index 266f9853306fc1e9c3a20f446df5bae9052f1d72..635567eb62935c653210df8d9888f53decf6410b 100644
--- a/Source/core/svg/SVGZoomEvent.h
+++ b/Source/core/svg/SVGZoomEvent.h
@@ -30,7 +30,10 @@ namespace WebCore {
 
 class SVGZoomEvent FINAL : public UIEvent {
 public:
-    static PassRefPtr<SVGZoomEvent> create() { return adoptRef(new SVGZoomEvent); }
+    static PassRefPtrWillBeRawPtr<SVGZoomEvent> create()
+    {
+        return adoptRefWillBeRefCountedGarbageCollected(new SVGZoomEvent);
+    }
 
     // 'SVGZoomEvent' functions
     PassRefPtr<SVGRectTearOff> zoomRectScreen() const;