Blink side of requestSyncEvents() function.

public/web/WebServiceWorkerContextClient.h

Index: public/web/WebServiceWorkerContextClient.h
diff --git a/public/web/WebServiceWorkerContextClient.h b/public/web/WebServiceWorkerContextClient.h
index 6f0d7eb63524167537c4fbab2703b66ef8b1c9b0..25c00b35fbfe0d6e0aa1fa60604f6978618a565c 100644
--- a/public/web/WebServiceWorkerContextClient.h
+++ b/public/web/WebServiceWorkerContextClient.h
@@ -99,6 +99,11 @@ public:
     // 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