The blink half of the new ServiceWorker 'sync' event.

public/web/WebServiceWorkerContextProxy.h

Index: public/web/WebServiceWorkerContextProxy.h
diff --git a/public/web/WebServiceWorkerContextProxy.h b/public/web/WebServiceWorkerContextProxy.h
index d6d02a137326cfe72a5f17b57e0a6ad7511657f7..df5865b4120c0306e7c7bd6db317ef6317bd37fe 100644
--- a/public/web/WebServiceWorkerContextProxy.h
+++ b/public/web/WebServiceWorkerContextProxy.h
@@ -50,6 +50,10 @@ public:
 
     virtual void dispatchMessageEvent(const WebString& message, const WebMessagePortChannelArray& channels) = 0;
 
+    // Once the ServiceWorker has finished handling the sync event
+    // didHandleSyncEvent is called on the context client.
+    virtual void dispatchSyncEvent(int syncEventID) = 0;
+
     virtual void resumeWorkerContext() { }
     virtual void attachDevTools() { }
     virtual void reattachDevTools(const WebString& savedState) { }