Cleanup remaining class/struct fwd declarations

google_apis/gaia/oauth2_token_service_delegate.h

 // Copyright 2015 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_OAUTH2_TOKEN_SERVICE_DELEGATE_H_
 #define GOOGLE_APIS_GAIA_OAUTH2_TOKEN_SERVICE_DELEGATE_H_
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "google_apis/gaia/gaia_auth_util.h"
 #include "google_apis/gaia/oauth2_token_service.h"
 #include "net/base/backoff_entry.h"
 
 namespace net {
 class URLRequestContextGetter;
 }
 
-class SigninClient;
-
 // Abstract base class to fetch and maintain refresh tokens from various
 // entities. Concrete subclasses should implement RefreshTokenIsAvailable and
 // CreateAccessTokenFetcher properly.
 class OAuth2TokenServiceDelegate {
  public:
   OAuth2TokenServiceDelegate();
   virtual ~OAuth2TokenServiceDelegate();
 
   virtual OAuth2AccessTokenFetcher* CreateAccessTokenFetcher(
       const std::string& account_id,
@@ skipping 61 matching lines @@
   void StartBatchChanges();
   void EndBatchChanges();
 
   // The depth of batch changes.
   int batch_change_depth_;
 
   DISALLOW_COPY_AND_ASSIGN(OAuth2TokenServiceDelegate);
 };
 
 #endif  // GOOGLE_APIS_GAIA_OAUTH2_TOKEN_SERVICE_DELEGATE_H_