chrome: Cleanup class/struct forward declarations

chrome/browser/chromeos/login/enrollment/auto_enrollment_controller.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 CHROME_BROWSER_CHROMEOS_LOGIN_ENROLLMENT_AUTO_ENROLLMENT_CONTROLLER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_ENROLLMENT_AUTO_ENROLLMENT_CONTROLLER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_list.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/chromeos/policy/auto_enrollment_client.h"
 #include "chrome/browser/chromeos/settings/device_settings_service.h"
 
-namespace policy {
-class ServerBackedStateKeysBroker;
-}
-
 namespace chromeos {
 
 // Drives the forced re-enrollment check (for historical reasons called
 // auto-enrollment check), running an AutoEnrollmentClient if appropriate to
 // make a decision.
 class AutoEnrollmentController {
  public:
   typedef base::CallbackList<void(policy::AutoEnrollmentState)>
       ProgressCallbackList;
 
@@ skipping 62 matching lines @@
   base::Timer safeguard_timer_;
 
   base::WeakPtrFactory<AutoEnrollmentController> client_start_weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AutoEnrollmentController);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_ENROLLMENT_AUTO_ENROLLMENT_CONTROLLER_H_