Reland of Call dispatcher's releaseRegistration when done with registrations

public/platform/modules/background_sync/WebSyncProvider.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebSyncProvider_h
 #define WebSyncProvider_h
 
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/WebCommon.h"
 #include "public/platform/WebString.h"
@@ skipping 36 matching lines @@
     // Does not take ownership of the WebServiceWorkerRegistration.
     virtual void getPermissionStatus(blink::WebSyncRegistration::Periodicity, WebServiceWorkerRegistration*, WebSyncGetPermissionStatusCallbacks*) = 0;
 
     // Takes ownership of the WebSyncNotifyWhenDoneCallbacks.
     virtual void notifyWhenDone(int64_t syncId, WebSyncNotifyWhenDoneCallbacks* callbacks)
     {
         // TODO(jkarlin): After landing both legs of the notifyWhenDone CLs, make this a pure virtual function.
         callbacks->onError(new WebSyncError(WebSyncError::ErrorTypeAbort, "Function not implemented."));
         delete callbacks;
     }
+
+    // Takes ownership of the WebServiceWorkerRegistration.
+    virtual void trackRegistration(WebSyncRegistration* registration)
+    {
+        // TODO(jkarlin): After landing both legs of the releaseRegistration CLs, make this a pure virtual function.
+        return;
+    }
+
+    virtual void releaseRegistration(int64_t syncId)
+    {
+        // TODO(jkarlin): After landing both legs of the releaseRegistration CLs, make this a pure virtual function.
+        return;
+    }
 };
 
 } // namespace blink
 
 #endif // WebSyncProvider_h