chrome: Cleanup class/struct forward declarations

chrome/browser/chromeos/extensions/users_private/users_private_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 CHROME_BROWSER_CHROMEOS_EXTENSIONS_USERS_PRIVATE_USERS_PRIVATE_DELEGATE_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_USERS_PRIVATE_USERS_PRIVATE_DELEGATE_H_
 
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "chrome/browser/extensions/api/settings_private/prefs_util.h"
 #include "chrome/common/extensions/api/users_private.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "extensions/browser/extension_function.h"
 
 class Profile;
 
-namespace base {
-class Value;
-}
-
 namespace extensions {
 
 // Provides prefs access for managing users.
 // Use UsersPrivateDelegateFactory to create a UsersPrivateDelegate object.
 class UsersPrivateDelegate : public KeyedService {
  public:
   explicit UsersPrivateDelegate(Profile* profile);
   ~UsersPrivateDelegate() override;
 
   // Gets a PrefsUtil object used for persisting settings.
   // The caller does not own the returned object.
   virtual PrefsUtil* GetPrefsUtil();
 
  protected:
   Profile* profile_;  // weak; not owned by us
   std::unique_ptr<PrefsUtil> prefs_util_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(UsersPrivateDelegate);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_USERS_PRIVATE_USERS_PRIVATE_DELEGATE_H_