ServiceWorker: Introduce ExtendableMessageEvent to replace MessageEvent

Source/web/ServiceWorkerGlobalScopeClientImpl.cpp

Index: Source/web/ServiceWorkerGlobalScopeClientImpl.cpp
diff --git a/Source/web/ServiceWorkerGlobalScopeClientImpl.cpp b/Source/web/ServiceWorkerGlobalScopeClientImpl.cpp
index 36c0ed46d0d4248adfe79a384ff79e9a41ab39b4..de15739819695711acdfc5eda56321f708029f7f 100644
--- a/Source/web/ServiceWorkerGlobalScopeClientImpl.cpp
+++ b/Source/web/ServiceWorkerGlobalScopeClientImpl.cpp
@@ -113,6 +113,11 @@ void ServiceWorkerGlobalScopeClientImpl::didHandleCrossOriginConnectEvent(int co
     m_client.didHandleCrossOriginConnectEvent(connectEventID, acceptConnect);
 }
 
+void ServiceWorkerGlobalScopeClientImpl::didHandleMessageEvent(int messageEventID, WebServiceWorkerEventResult result)
+{
+    m_client.didHandleMessageEvent(messageEventID, result);
+}
+
 void ServiceWorkerGlobalScopeClientImpl::postMessageToClient(const WebString& clientUUID, const WebString& message, PassOwnPtr<WebMessagePortChannelArray> webChannels)
 {
     m_client.postMessageToClient(clientUUID, message, webChannels.leakPtr());