Unregister GCMInvalidationBridge from GCMDriver when user signs out.

components/invalidation/gcm_invalidation_bridge.h

 // Copyright 2014 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 COMPONENTS_INVALIDATION_GCM_INVALIDATION_BRIDGE_H_
 #define COMPONENTS_INVALIDATION_GCM_INVALIDATION_BRIDGE_H_
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 68 matching lines @@
 
   void Register(syncer::GCMNetworkChannelDelegate::RegisterCallback callback);
 
   void SubscribeForIncomingMessages();
 
   void RegisterFinished(
       syncer::GCMNetworkChannelDelegate::RegisterCallback callback,
       const std::string& registration_id,
       gcm::GCMClient::Result result);
 
+  void Unregister();
+
+  static void UnregisterFinishedNoOp(gcm::GCMClient::Result result);
+
  private:
   gcm::GCMDriver* const gcm_driver_;
   IdentityProvider* const identity_provider_;
 
   base::WeakPtr<Core> core_;
   scoped_refptr<base::SingleThreadTaskRunner> core_thread_task_runner_;
 
   // Fields related to RequestToken function.
   scoped_ptr<OAuth2TokenService::Request> access_token_request_;
   syncer::GCMNetworkChannelDelegate::RequestTokenCallback
       request_token_callback_;
   bool subscribed_for_incoming_messages_;
 
   base::WeakPtrFactory<GCMInvalidationBridge> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GCMInvalidationBridge);
 };
 
 }  // namespace invalidation
 
 #endif  // COMPONENTS_INVALIDATION_GCM_INVALIDATION_BRIDGE_H_