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

Source/modules/speech/SpeechRecognitionEvent.h

Index: Source/modules/speech/SpeechRecognitionEvent.h
diff --git a/Source/modules/speech/SpeechRecognitionEvent.h b/Source/modules/speech/SpeechRecognitionEvent.h
index e716305762420dfa1e54876a860e9c08f0ef2140..7ab8eb66662a85409f093007c0c7a0f81a5e5e01 100644
--- a/Source/modules/speech/SpeechRecognitionEvent.h
+++ b/Source/modules/speech/SpeechRecognitionEvent.h
@@ -65,13 +65,15 @@ public:
     // Event
     virtual const AtomicString& interfaceName() const OVERRIDE;
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     SpeechRecognitionEvent();
     SpeechRecognitionEvent(const AtomicString&, const SpeechRecognitionEventInit&);
     SpeechRecognitionEvent(const AtomicString& eventName, unsigned long resultIndex, PassRefPtrWillBeRawPtr<SpeechRecognitionResultList> results);
 
     unsigned long m_resultIndex;
-    RefPtrWillBePersistent<SpeechRecognitionResultList> m_results;
+    RefPtrWillBeMember<SpeechRecognitionResultList> m_results;
 };
 
 } // namespace WebCore