Move Event to oilpan's heap

Source/core/events/Event.h

Index: Source/core/events/Event.h
diff --git a/Source/core/events/Event.h b/Source/core/events/Event.h
index ee540781f2b1a0da62239e60dfc02cf7310e7688..43baf839cd1254387bc6c5ddbd9eddce7b5567d3 100644
--- a/Source/core/events/Event.h
+++ b/Source/core/events/Event.h
@@ -46,7 +46,7 @@ public:
     bool cancelable;
 };
 
-class Event : public RefCounted<Event>,  public ScriptWrappable {
+class Event : public RefCountedWillBeRefCountedGarbageCollected<Event>,  public ScriptWrappable {
 public:
     enum PhaseType {
         NONE                = 0,