Move UserContext to its own file

chrome/browser/chromeos/login/app_launch_signin_screen.h

 // Copyright 2013 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_APP_LAUNCH_SIGNIN_SCREEN_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_APP_LAUNCH_SIGNIN_SCREEN_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/chromeos/login/auth/authenticator.h"
 #include "chrome/browser/chromeos/login/auth/login_status_consumer.h"
+#include "chrome/browser/chromeos/login/users/user.h"
 #include "chrome/browser/chromeos/login/users/user_manager.h"
 #include "chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h"
 
 namespace chromeos {
 
 class OobeUI;
 
 // The app launch signin screen shows the user pod of the device owner
 // and requires the user to login in order to access the network dialog.
 // This screen is quite similar to the standard lock screen, but we do not
@@ skipping 72 matching lines @@
   UserList owner_user_list_;
 
   static UserManager* test_user_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(AppLaunchSigninScreen);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_APP_LAUNCH_SIGNIN_SCREEN_H_