Refactor GCMNetworkChannelDelegateImpl

sync/notifier/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 SYNC_NOTIFIER_GCM_NETWORK_CHANNEL_DELEGATE_H_
 #define SYNC_NOTIFIER_GCM_NETWORK_CHANNEL_DELEGATE_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 13 matching lines @@
 // thread and callbacks should be invoked there as well.
 class GCMNetworkChannelDelegate {
  public:
   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;
 
   virtual ~GCMNetworkChannelDelegate() {}
 
+  virtual void Initialize() = 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;
 
   // Register with GCMProfileService. Callback should be called with either
   // registration id or error code.
   virtual void Register(RegisterCallback callback) = 0;
 };
 }  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_GCM_NETWORK_CHANNEL_DELEGATE_H_