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

Source/core/workers/AbstractWorker.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 30 matching lines @@
 #include "wtf/RefPtr.h"
 #include "wtf/text/AtomicStringHash.h"
 
 namespace WebCore {
 
 class ExceptionState;
 class KURL;
 class ExecutionContext;
 
 class AbstractWorker : public RefCountedWillBeRefCountedGarbageCollected<AbstractWorker>, public EventTargetWithInlineData, public ActiveDOMObject {
-    DEFINE_EVENT_TARGET_REFCOUNTING(RefCountedWillBeRefCountedGarbageCollected<AbstractWorker>);
+    REFCOUNTED_EVENT_TARGET(AbstractWorker);
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(AbstractWorker);
 public:
     // EventTarget APIs
     virtual ExecutionContext* executionContext() const OVERRIDE FINAL { return ActiveDOMObject::executionContext(); }
 
     DEFINE_STATIC_ATTRIBUTE_EVENT_LISTENER(error);
 
     AbstractWorker(ExecutionContext*);
     virtual ~AbstractWorker();
 
-    virtual void trace(Visitor*) { }
-
 protected:
     // Helper function that converts a URL to an absolute URL and checks the result for validity.
     KURL resolveURL(const String& url, ExceptionState&);
     intptr_t asID() const { return reinterpret_cast<intptr_t>(this); }
 };
 
 } // namespace WebCore
 
 #endif // AbstractWorker_h