Revert of Enable Oilpan by default in modules/speech/

Source/modules/speech/SpeechSynthesisEvent.h

Index: Source/modules/speech/SpeechSynthesisEvent.h
diff --git a/Source/modules/speech/SpeechSynthesisEvent.h b/Source/modules/speech/SpeechSynthesisEvent.h
index 0634c55f94c07ac1d5e249ee4bb2f50fcdf37f68..a85b670db734b002391538cfa0c4a7d7b2173fb4 100644
--- a/Source/modules/speech/SpeechSynthesisEvent.h
+++ b/Source/modules/speech/SpeechSynthesisEvent.h
@@ -27,6 +27,7 @@
 #define SpeechSynthesisEvent_h
 
 #include "modules/EventModules.h"
+#include "wtf/PassRefPtr.h"
 
 namespace WebCore {
 
@@ -41,10 +42,7 @@
 
     virtual const AtomicString& interfaceName() const OVERRIDE { return EventNames::SpeechSynthesisEvent; }
 
-    virtual void trace(Visitor* visitor) OVERRIDE
-    {
-        Event::trace(visitor);
-    }
+    virtual void trace(Visitor*) OVERRIDE;
 
 private:
     SpeechSynthesisEvent();