Make GCMProfileService own GCMDriver, instead of deriving from it

google_apis/gcm/gcm_client.h

 // Copyright 2013 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 GOOGLE_APIS_GCM_GCM_CLIENT_H_
 #define GOOGLE_APIS_GCM_GCM_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 23 matching lines @@
 
 // Interface that encapsulates the network communications with the Google Cloud
 // Messaging server. This interface is not supposed to be thread-safe.
 class GCM_EXPORT GCMClient {
  public:
   enum Result {
     // Successful operation.
     SUCCESS,
     // Invalid parameter.
     INVALID_PARAMETER,
+    // GCM is disabled.
+    GCM_DISABLED,
     // Profile not signed in.
     NOT_SIGNED_IN,
     // Previous asynchronous operation is still pending to finish. Certain
     // operation, like register, is only allowed one at a time.
     ASYNC_OPERATION_PENDING,
     // Network socket error.
     NETWORK_ERROR,
     // Problem at the server.
     SERVER_ERROR,
     // Exceeded the specified TTL during message sending.
@@ skipping 176 matching lines @@
   // Clear all recorded GCM activity logs.
   virtual void ClearActivityLogs() = 0;
 
   // Gets internal states and statistics.
   virtual GCMStatistics GetStatistics() const = 0;
 };
 
 }  // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_GCM_CLIENT_H_