Blink side of requestSyncEvents() function.

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 81 matching lines @@
     virtual void didHandleFetchEvent(int fetchEventID) { }
     virtual void didHandleFetchEvent(int fetchEventID, const WebServiceWorkerResponse& response) { }
 
     // Ownership of the returned object is transferred to the caller.
     virtual WebServiceWorkerNetworkProvider* createServiceWorkerNetworkProvider(blink::WebDataSource*) { return 0; }
 
     // ServiceWorker specific method. Called after SyncEvent (dispatched via
     // WebServiceWorkerContextProxy) is handled by the ServiceWorker's script
     // context.
     virtual void didHandleSyncEvent(int syncEventID) { }
+
+    // Registers/Unregisters ServiceWorker interest in receiving sync events. If
+    // not registered, the sync event is not fired in order to conserve
+    // resources.
+    virtual void requestSyncEvents(int syncRegisterID, bool requested) { }
 };
 
 } // namespace blink
 
 #endif // WebWorkerContextClient_h