ServiceWorker: Introduce ServiceWorkerMessageEvent to replace MessageEvent (3/3).

Source/modules/serviceworkers/ServiceWorkerContainer.h

Index: Source/modules/serviceworkers/ServiceWorkerContainer.h
diff --git a/Source/modules/serviceworkers/ServiceWorkerContainer.h b/Source/modules/serviceworkers/ServiceWorkerContainer.h
index 57f78ff4bec1ed6c73578802acf4bdeabc0a0701..35cc9ecf010f33b40ae9f711945f6a81d7290266 100644
--- a/Source/modules/serviceworkers/ServiceWorkerContainer.h
+++ b/Source/modules/serviceworkers/ServiceWorkerContainer.h
@@ -78,13 +78,14 @@ public:
 
     // WebServiceWorkerProviderClient overrides.
     virtual void setController(WebServiceWorker*, bool shouldNotifyControllerChange) override;
-    virtual void dispatchMessageEvent(const WebString& message, const WebMessagePortChannelArray&) override;
+    virtual void dispatchMessageEvent(WebServiceWorker*, const WebString& message, const WebMessagePortChannelArray&) override;
 
     // EventTarget overrides.
     virtual ExecutionContext* executionContext() const override { return ContextLifecycleObserver::executionContext(); }
     virtual const AtomicString& interfaceName() const override;
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(controllerchange);
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(message);
 
 private:
     explicit ServiceWorkerContainer(ExecutionContext*);