Implement new invalidations ack tracking system

sync/notifier/p2p_invalidator.h

 // Copyright 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.
 //
 // An invalidator that uses p2p invalidations based on XMPP push
 // notifications.  Used only for sync integration tests.
 
 #ifndef SYNC_NOTIFIER_P2P_INVALIDATOR_H_
 #define SYNC_NOTIFIER_P2P_INVALIDATOR_H_
 
@@ skipping 88 matching lines @@
                  const std::string& invalidator_client_id,
                  P2PNotificationTarget send_notification_target);
 
   virtual ~P2PInvalidator();
 
   // Invalidator implementation.
   virtual void RegisterHandler(InvalidationHandler* handler) OVERRIDE;
   virtual void UpdateRegisteredIds(InvalidationHandler* handler,
                                    const ObjectIdSet& ids) OVERRIDE;
   virtual void UnregisterHandler(InvalidationHandler* handler) OVERRIDE;
-  virtual void Acknowledge(const invalidation::ObjectId& id,
-                           const AckHandle& ack_handle) OVERRIDE;
   virtual InvalidatorState GetInvalidatorState() const OVERRIDE;
   virtual void UpdateCredentials(
       const std::string& email, const std::string& token) OVERRIDE;
 
   // PushClientObserver implementation.
   virtual void OnNotificationsEnabled() OVERRIDE;
   virtual void OnNotificationsDisabled(
       notifier::NotificationsDisabledReason reason) OVERRIDE;
   virtual void OnIncomingNotification(
       const notifier::Notification& notification) OVERRIDE;
@@ skipping 19 matching lines @@
   bool notifications_enabled_;
   // Which set of clients should be sent notifications.
   P2PNotificationTarget send_notification_target_;
 
   DISALLOW_COPY_AND_ASSIGN(P2PInvalidator);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_P2P_INVALIDATOR_H_