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

Source/core/speech/SpeechInputEvent.h

Index: Source/core/speech/SpeechInputEvent.h
diff --git a/Source/core/speech/SpeechInputEvent.h b/Source/core/speech/SpeechInputEvent.h
index c7e622da9385ac67c09c5f3a1f9bf09a03e434fb..b09cd94aa019977ca7e51927e32dbc306a265bf5 100644
--- a/Source/core/speech/SpeechInputEvent.h
+++ b/Source/core/speech/SpeechInputEvent.h
@@ -45,11 +45,13 @@ public:
 
     virtual const AtomicString& interfaceName() const OVERRIDE;
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     SpeechInputEvent();
     SpeechInputEvent(const AtomicString& eventType, const SpeechInputResultArray& results);
 
-    RefPtrWillBePersistent<SpeechInputResultList> m_results;
+    RefPtrWillBeMember<SpeechInputResultList> m_results;
 };
 
 } // namespace WebCore