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

Source/modules/speech/SpeechRecognitionEvent.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 74 matching lines @@
     , m_results(results)
 {
     ScriptWrappable::init(this);
 }
 
 SpeechRecognitionEvent::~SpeechRecognitionEvent()
 {
     ScriptWrappable::init(this);
 }
 
+void SpeechRecognitionEvent::trace(Visitor* visitor)
+{
+    visitor->trace(m_results);
+    Event::trace(visitor);
+}
+
 } // namespace WebCore