Notify SyncNetworkChannel about GCM connection state

components/invalidation/gcm_network_channel_delegate.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_NETWORK_CHANNEL_DELEGATE_H_
 #define COMPONENTS_INVALIDATION_GCM_NETWORK_CHANNEL_DELEGATE_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "components/gcm_driver/gcm_client.h"
 
 class GoogleServiceAuthError;
 
 namespace syncer {
 
 // Delegate for GCMNetworkChannel.
 // GCMNetworkChannel needs Register to register with GCM client and obtain gcm
 // registration id. This id is used for building URL to cache invalidation
 // endpoint.
 // It needs RequestToken and InvalidateToken to get access token to include it
 // in HTTP message to server.
 // GCMNetworkChannel lives on IO thread therefore calls will be made on IO
 // thread and callbacks should be invoked there as well.
 class GCMNetworkChannelDelegate {
  public:
+  enum ConnectionState {
+    CONNECTION_STATE_OFFLINE,
+    CONNECTION_STATE_ONLINE
+  };
+
   typedef base::Callback<void(const GoogleServiceAuthError& error,
                               const std::string& token)> RequestTokenCallback;
   typedef base::Callback<void(const std::string& registration_id,
                               gcm::GCMClient::Result result)> RegisterCallback;
   typedef base::Callback<void(const std::string& message,
                               const std::string& echo_token)> MessageCallback;
+  typedef base::Callback<void(ConnectionState connection_state)>
+      ConnectionStateCallback;
 
   virtual ~GCMNetworkChannelDelegate() {}
 
-  virtual void Initialize() = 0;
+  virtual void Initialize(ConnectionStateCallback callback) = 0;
   // Request access token. Callback should be called either with access token or
   // error code.
   virtual void RequestToken(RequestTokenCallback callback) = 0;
   // Invalidate access token that was rejected by server.
   virtual void InvalidateToken(const std::string& token) = 0;
 
   // Request registration_id from GCMService. Callback should be called with
   // either registration id or error code.
   virtual void Register(RegisterCallback callback) = 0;
   // Provide callback for incoming messages from GCM.
   virtual void SetMessageReceiver(MessageCallback callback) = 0;
 };
 }  // namespace syncer
 
 #endif  // COMPONENTS_INVALIDATION_GCM_NETWORK_CHANNEL_DELEGATE_H_