Oilpan: Allocate all EventTarget derived types on the manged heap.

Source/core/page/EventSource.h

Index: Source/core/page/EventSource.h
diff --git a/Source/core/page/EventSource.h b/Source/core/page/EventSource.h
index bbd7d3827a57563417c248abef82605b5fbdda78..38b795fa2d62a15d7e0fcf300da2aa394d3131c2 100644
--- a/Source/core/page/EventSource.h
+++ b/Source/core/page/EventSource.h
@@ -53,7 +53,8 @@ class ThreadableLoader;
 
 class EventSource FINAL : public RefCountedWillBeRefCountedGarbageCollected<EventSource>, public ScriptWrappable, public EventTargetWithInlineData, private ThreadableLoaderClient, public ActiveDOMObject {
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
-    DEFINE_EVENT_TARGET_REFCOUNTING(RefCountedWillBeRefCountedGarbageCollected<EventSource>);
+    REFCOUNTED_EVENT_TARGET(EventSource);
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(EventSource);
 public:
     static PassRefPtrWillBeRawPtr<EventSource> create(ExecutionContext*, const String& url, const Dictionary&, ExceptionState&);
     virtual ~EventSource();
@@ -87,8 +88,6 @@ public:
     // asynchronous events from the loader won't be invoked.
     virtual void stop() OVERRIDE;
 
-    void trace(Visitor*) { }
-
 private:
     EventSource(ExecutionContext*, const KURL&, const Dictionary&);