Implement Invalidator::Acknowledge

chrome/browser/sync/invalidation_frontend.h

 // Copyright (c) 2012 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 CHROME_BROWSER_SYNC_INVALIDATION_FRONTEND_H_
 #define CHROME_BROWSER_SYNC_INVALIDATION_FRONTEND_H_
 
 #include "sync/notifier/invalidation_util.h"
 
 namespace syncer {
@@ skipping 58 matching lines @@
       const syncer::ObjectIdSet& ids) = 0;
 
   // Stops sending notifications to |handler|.  |handler| must not be NULL, and
   // it must already be registered.  Note that this doesn't unregister the IDs
   // associated with |handler|.
   //
   // Handler registrations are persisted across restarts of sync.
   virtual void UnregisterInvalidationHandler(
       syncer::InvalidationHandler* handler) = 0;
 
+  // TODO(dcheng): Add a comment.
+  virtual void AcknowledgeInvalidation(const invalidation::ObjectId& id,
+                                       const syncer::AckHandle& ack_handle) = 0;
+
   // Returns the current invalidator state.  When called from within
   // InvalidationHandler::OnInvalidatorStateChange(), this must return
   // the updated state.
   virtual syncer::InvalidatorState GetInvalidatorState() const = 0;
 
  protected:
   virtual ~InvalidationFrontend() { }
 };
 
 #endif  // CHROME_BROWSER_SYNC_INVALIDATION_FRONTEND_H_