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

Source/core/speech/SpeechInputEvent.cpp

 /*
  * Copyright (C) 2010 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 51 matching lines @@
 
 SpeechInputEvent::~SpeechInputEvent()
 {
 }
 
 const AtomicString& SpeechInputEvent::interfaceName() const
 {
     return EventNames::SpeechInputEvent;
 }
 
+void SpeechInputEvent::trace(Visitor* visitor)
+{
+    visitor->trace(m_results);
+    Event::trace(visitor);
+}
+
 } // namespace WebCore
 
 #endif // ENABLE(INPUT_SPEECH)