chrome: Cleanup class/struct forward declarations

chrome/browser/ui/webui/options/sync_setup_handler.h

 // Copyright (c) 2012 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 CHROME_BROWSER_UI_WEBUI_OPTIONS_SYNC_SETUP_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_OPTIONS_SYNC_SETUP_HANDLER_H_
 
 #include <memory>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "chrome/browser/sync/sync_startup_tracker.h"
 #include "chrome/browser/ui/webui/options/options_ui.h"
 #include "chrome/browser/ui/webui/signin/login_ui_service.h"
 
 class LoginUIService;
-class SigninManagerBase;
 
 namespace browser_sync {
 class ProfileSyncService;
 }  // namespace browser_sync
 
-namespace content {
-class WebContents;
-}  // namespace content
-
 namespace signin_metrics {
 enum class AccessPoint;
 }  // namespace signin_metrics
 
 namespace syncer {
 class SyncSetupInProgressHandle;
 }  // namespace syncer
 
 class SyncSetupHandler : public options::OptionsPageUIHandler,
                          public SyncStartupTracker::Observer,
@@ skipping 132 matching lines @@
   bool configuring_sync_;
 
   // The OneShotTimer object used to timeout of starting the sync backend
   // service.
   std::unique_ptr<base::OneShotTimer> backend_start_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncSetupHandler);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_OPTIONS_SYNC_SETUP_HANDLER_H_