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

Source/modules/websockets/CloseEvent.h

 /*
  * Copyright (C) 2011 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
@@ skipping 54 matching lines @@
         return adoptRef(new CloseEvent(type, initializer));
     }
 
     bool wasClean() const { return m_wasClean; }
     unsigned short code() const { return m_code; }
     String reason() const { return m_reason; }
 
     // Event function.
     virtual const AtomicString& interfaceName() const OVERRIDE { return EventNames::CloseEvent; }
 
+    virtual void trace(Visitor* visitor) OVERRIDE { Event::trace(visitor); }
+
 private:
     CloseEvent()
         : Event(EventTypeNames::close, false, false)
         , m_wasClean(false)
         , m_code(0)
     {
         ScriptWrappable::init(this);
     }
 
     CloseEvent(bool wasClean, int code, const String& reason)
@@ skipping 15 matching lines @@
     }
 
     bool m_wasClean;
     unsigned short m_code;
     String m_reason;
 };
 
 } // namespace WebCore
 
 #endif // CloseEvent_h