Implement Invalidator::Acknowledge

sync/notifier/invalidator.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.
 //
 // Interface to the invalidator, which is an object that receives
 // invalidations for registered object IDs. The corresponding
 // InvalidationHandler is notifier when such an event occurs.
 
 #ifndef SYNC_NOTIFIER_INVALIDATOR_H_
 #define SYNC_NOTIFIER_INVALIDATOR_H_
@@ skipping 46 matching lines @@
   // not be NULL, and must already be registered.  An ID must be registered for
   // at most one handler.
   virtual void UpdateRegisteredIds(InvalidationHandler* handler,
                                    const 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|.
   virtual void UnregisterHandler(InvalidationHandler* handler) = 0;
 
+  // TODO(dcheng): Add comment.
+  virtual void Acknowledge(const invalidation::ObjectId& id,
+                           const AckHandle& ack_handle) = 0;
+
   // Returns the current invalidator state.  When called from within
   // InvalidationHandler::OnInvalidatorStateChange(), this must return
   // the updated state.
   virtual InvalidatorState GetInvalidatorState() const = 0;
 
   // SetUniqueId must be called once, before any call to
   // UpdateCredentials.  |unique_id| should be a non-empty globally
   // unique string.
   virtual void SetUniqueId(const std::string& unique_id) = 0;
 
@@ skipping 10 matching lines @@
 
   // This is here only to support the old p2p notification implementation,
   // which is still used by sync integration tests.
   // TODO(akalin): Remove this once we move the integration tests off p2p
   // notifications.
   virtual void SendInvalidation(const ObjectIdStateMap& id_state_map) = 0;
 };
 }  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_INVALIDATOR_H_