Remove task.h and finish base::Bind() migration.

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h

 // Copyright (c) 2011 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_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_
 #pragma once
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
-#include "base/task.h"
 #include "chrome/browser/browsing_data_remover.h"
 #include "chrome/browser/chromeos/login/help_app_launcher.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/system_key_event_listener.h"
 #include "chrome/browser/ui/webui/chromeos/login/base_screen_handler.h"
 #include "content/browser/webui/web_ui.h"
 #include "content/public/browser/notification_observer.h"
 
 class BrowsingDataRemover;
 
@@ skipping 250 matching lines @@
 
   // CapsLock state change notifier instance;
   SystemKeyEventListener* key_event_listener_;
 
   DISALLOW_COPY_AND_ASSIGN(SigninScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_SIGNIN_SCREEN_HANDLER_H_