Push API: define push event on Service Worker.

public/web/WebServiceWorkerContextClient.h

 /*
  * Copyright (C) 2013 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 92 matching lines @@
     // ServiceWorker's script context. When no response is provided, the browser
     // should fallback to native fetch.
     virtual void didHandleFetchEvent(int fetchEventID) { }
     virtual void didHandleFetchEvent(int fetchEventID, const WebServiceWorkerResponse& response) { }
 
     // ServiceWorker specific method. Called after SyncEvent (dispatched via
     // WebServiceWorkerContextProxy) is handled by the ServiceWorker's script
     // context.
     virtual void didHandleSyncEvent(int syncEventID) { }
 
+    // ServiceWorker specific method. Called after PushEvent (dispatched via
+    // WebServiceWorkerContextProxy) is handled by the ServiceWorker's script
+    // context.
+    virtual void didHandlePushEvent(int eventID) { }
+
     // Ownership of the returned object is transferred to the caller.
     virtual WebServiceWorkerNetworkProvider* createServiceWorkerNetworkProvider(blink::WebDataSource*) { return 0; }
 
     // Ownership of the passed callbacks is transferred to the callee, callee
     // should delete the callbacks after calling either onSuccess or onError.
     // WebServiceWorkerClientsInfo and WebServiceWorkerError ownerships are
     // passed to the WebServiceWorkerClientsCallbacks implementation.
     virtual void getClients(WebServiceWorkerClientsCallbacks*) { BLINK_ASSERT_NOT_REACHED(); }
 
     // Callee receives ownership of the passed vector.
     // FIXME: Blob refs should be passed to maintain ref counts. crbug.com/351753
     virtual void postMessageToClient(int clientID, const WebString&, WebMessagePortChannelArray*) { BLINK_ASSERT_NOT_REACHED(); }
 };
 
 } // namespace blink
 
 #endif // WebWorkerContextClient_h