Cleanup remaining class/struct fwd declarations

components/signin/ios/browser/profile_oauth2_token_service_ios_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 COMPONENTS_SIGNIN_IOS_BROWSER_PROFILE_OAUTH2_TOKEN_SERVICE_IOS_DELEGATE_H_
 #define COMPONENTS_SIGNIN_IOS_BROWSER_PROFILE_OAUTH2_TOKEN_SERVICE_IOS_DELEGATE_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "components/signin/core/browser/signin_error_controller.h"
 #include "google_apis/gaia/oauth2_token_service_delegate.h"
 
 class AccountTrackerService;
 class ProfileOAuth2TokenServiceIOSProvider;
+class SigninClient;
 
 class ProfileOAuth2TokenServiceIOSDelegate : public OAuth2TokenServiceDelegate {
  public:
   ProfileOAuth2TokenServiceIOSDelegate(
       SigninClient* client,
       std::unique_ptr<ProfileOAuth2TokenServiceIOSProvider> provider,
       AccountTrackerService* account_tracker_service,
       SigninErrorController* signin_error_controller);
   ~ProfileOAuth2TokenServiceIOSDelegate() override;
 
@@ skipping 90 matching lines @@
   SigninClient* client_;
   std::unique_ptr<ProfileOAuth2TokenServiceIOSProvider> provider_;
   AccountTrackerService* account_tracker_service_;
 
   // The error controller with which this instance was initialized, or NULL.
   SigninErrorController* signin_error_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileOAuth2TokenServiceIOSDelegate);
 };
 #endif  // COMPONENTS_SIGNIN_IOS_BROWSER_PROFILE_OAUTH2_TOKEN_SERVICE_IOS_DELEGATE_H_