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

Source/modules/speech/SpeechRecognitionEvent.cpp

Index: Source/modules/speech/SpeechRecognitionEvent.cpp
diff --git a/Source/modules/speech/SpeechRecognitionEvent.cpp b/Source/modules/speech/SpeechRecognitionEvent.cpp
index 28677c24671a2dc02aa0429abd29dd7aa1dae0c2..b40fe9bd0f4d3eda55adc786803db9a75c0b4660 100644
--- a/Source/modules/speech/SpeechRecognitionEvent.cpp
+++ b/Source/modules/speech/SpeechRecognitionEvent.cpp
@@ -92,4 +92,10 @@ SpeechRecognitionEvent::~SpeechRecognitionEvent()
     ScriptWrappable::init(this);
 }
 
+void SpeechRecognitionEvent::trace(Visitor* visitor)
+{
+    visitor->trace(m_results);
+    Event::trace(visitor);
+}
+
 } // namespace WebCore