Oilpan: move Worker objects to the oilpan heap.

Source/core/workers/Worker.h

Index: Source/core/workers/Worker.h
diff --git a/Source/core/workers/Worker.h b/Source/core/workers/Worker.h
index 1f1067bdd2663de34797b3c710e1a5cf73a7bad9..8e8771ae70cddf6cb2c505b068f998845219a970 100644
--- a/Source/core/workers/Worker.h
+++ b/Source/core/workers/Worker.h
@@ -34,6 +34,7 @@
 #include "core/events/ThreadLocalEventNames.h"
 #include "core/workers/AbstractWorker.h"
 #include "core/workers/WorkerScriptLoaderClient.h"
+#include "heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
@@ -48,7 +49,7 @@ class WorkerScriptLoader;
 
 class Worker FINAL : public AbstractWorker, public ScriptWrappable, private WorkerScriptLoaderClient {
 public:
-    static PassRefPtr<Worker> create(ExecutionContext*, const String& url, ExceptionState&);
+    static PassRefPtrWillBeRawPtr<Worker> create(ExecutionContext*, const String& url, ExceptionState&);
     virtual ~Worker();
 
     virtual const AtomicString& interfaceName() const OVERRIDE;
@@ -62,6 +63,8 @@ public:
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(message);
 
+    virtual void trace(Visitor*) OVERRIDE;
+
 private:
     explicit Worker(ExecutionContext*);