Extract OAuth2AccessTokenFetcher interface.

google_apis/gaia/merge_session_helper.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 GOOGLE_APIS_GAIA_MERGE_SESSION_HELPER_H_
 #define GOOGLE_APIS_GAIA_MERGE_SESSION_HELPER_H_
 
 #include <deque>
 
 #include "base/observer_list.h"
 #include "google_apis/gaia/gaia_auth_consumer.h"
 #include "google_apis/gaia/ubertoken_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
 
 class GaiaAuthFetcher;
 class GoogleServiceAuthError;
 class OAuth2TokenService;
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 // Merges a Google account known to Chrome into the cookie jar.  When merging
@@ skipping 82 matching lines @@
   std::deque<std::string> accounts_;
 
   // List of observers to notify when merge session completes.
   // Makes sure list is empty on destruction.
   ObserverList<Observer, true> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(MergeSessionHelper);
 };
 
 #endif  // GOOGLE_APIS_GAIA_MERGE_SESSION_HELPER_H_