Make Event RefCountedGarbageCollected and implement trace() methods to the Event hierarcy

Source/core/events/GestureEvent.cpp

 /*
  * Copyright (C) 2012 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:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 76 matching lines @@
 {
 }
 
 GestureEvent::GestureEvent(const AtomicString& type, PassRefPtr<AbstractView> view, int screenX, int screenY, int clientX, int clientY, bool ctrlKey, bool altKey, bool shiftKey, bool metaKey, float deltaX, float deltaY)
     : MouseRelatedEvent(type, true, true, view, 0, IntPoint(screenX, screenY), IntPoint(clientX, clientY), IntPoint(0, 0), ctrlKey, altKey, shiftKey, metaKey)
     , m_deltaX(deltaX)
     , m_deltaY(deltaY)
 {
 }
 
+void GestureEvent::trace(Visitor* visitor)
+{
+    MouseRelatedEvent::trace(visitor);
+}
+
 GestureEventDispatchMediator::GestureEventDispatchMediator(PassRefPtr<GestureEvent> gestureEvent)
     : EventDispatchMediator(gestureEvent)
 {
 }
 
 GestureEvent* GestureEventDispatchMediator::event() const
 {
     return toGestureEvent(EventDispatchMediator::event());
 }
 
 bool GestureEventDispatchMediator::dispatchEvent(EventDispatcher* dispatcher) const
 {
     dispatcher->dispatch();
     ASSERT(!event()->defaultPrevented());
     return event()->defaultHandled() || event()->defaultPrevented();
 }
 
 } // namespace WebCore