Oilpan: move core/workers to oilpan's heap.

Source/core/dom/MessagePort.h

Index: Source/core/dom/MessagePort.h
diff --git a/Source/core/dom/MessagePort.h b/Source/core/dom/MessagePort.h
index 65e0cba4e3b3af3d89386fe7efc09431a273b224..fb7094c10a9fc97898f7586d3ccf20961ee9dcc9 100644
--- a/Source/core/dom/MessagePort.h
+++ b/Source/core/dom/MessagePort.h
@@ -31,6 +31,7 @@
 #include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventListener.h"
 #include "core/events/EventTarget.h"
+#include "heap/Handle.h"
 #include "public/platform/WebMessagePortChannel.h"
 #include "public/platform/WebMessagePortChannelClient.h"
 #include "wtf/OwnPtr.h"
@@ -56,14 +57,15 @@ typedef Vector<RefPtr<MessagePort>, 1> MessagePortArray;
 // Not to be confused with blink::WebMessagePortChannelArray; this one uses Vector and OwnPtr instead of WebVector and raw pointers.
 typedef Vector<OwnPtr<blink::WebMessagePortChannel>, 1> MessagePortChannelArray;
 
-class MessagePort FINAL : public RefCounted<MessagePort>
+class MessagePort FINAL : public RefCountedWillBeRefCountedGarbageCollected<MessagePort>
     , public ActiveDOMObject
     , public EventTargetWithInlineData
     , public ScriptWrappable
     , public blink::WebMessagePortChannelClient {
-    REFCOUNTED_EVENT_TARGET(MessagePort);
+    DECLARE_GC_INFO;
+    DEFINE_EVENT_TARGET_REFCOUNTING(RefCountedWillBeRefCountedGarbageCollected<MessagePort>);
 public:
-    static PassRefPtr<MessagePort> create(ExecutionContext&);
+    static PassRefPtrWillBeRawPtr<MessagePort> create(ExecutionContext&);
     virtual ~MessagePort();
 
     void postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray*, ExceptionState&);
@@ -103,6 +105,8 @@ public:
     // A port gets neutered when it is transferred to a new owner via postMessage().
     bool isNeutered() const { return !m_entangledChannel; }
 
+    void trace(Visitor*) { }
+
 private:
     explicit MessagePort(ExecutionContext&);