Simplify adding callbacks.

chrome/chrome_browser_ui.gypi

 # Copyright 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.
 
 {
   'targets': [
     {
       'target_name': 'browser_ui',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 1870 matching lines @@
         'browser/ui/webui/chromeos/diagnostics/diagnostics_ui.cc',
         'browser/ui/webui/chromeos/diagnostics/diagnostics_ui.h',
         'browser/ui/webui/chromeos/drive_internals_ui.cc',
         'browser/ui/webui/chromeos/drive_internals_ui.h',
         'browser/ui/webui/chromeos/imageburner/imageburner_ui.cc',
         'browser/ui/webui/chromeos/imageburner/imageburner_ui.h',
         'browser/ui/webui/chromeos/keyboard_overlay_ui.cc',
         'browser/ui/webui/chromeos/keyboard_overlay_ui.h',
         'browser/ui/webui/chromeos/login/base_screen_handler.cc',
         'browser/ui/webui/chromeos/login/base_screen_handler.h',
+        'browser/ui/webui/chromeos/login/base_screen_handler_utils.h',
         'browser/ui/webui/chromeos/login/core_oobe_handler.cc',
         'browser/ui/webui/chromeos/login/core_oobe_handler.h',
         'browser/ui/webui/chromeos/login/enterprise_oauth_enrollment_screen_handler.cc',
         'browser/ui/webui/chromeos/login/enterprise_oauth_enrollment_screen_handler.h',
         'browser/ui/webui/chromeos/login/error_screen_handler.cc',
         'browser/ui/webui/chromeos/login/error_screen_handler.h',
         'browser/ui/webui/chromeos/login/eula_screen_handler.cc',
         'browser/ui/webui/chromeos/login/eula_screen_handler.h',
         'browser/ui/webui/chromeos/login/kiosk_app_menu_handler.cc',
         'browser/ui/webui/chromeos/login/kiosk_app_menu_handler.h',
@@ skipping 981 matching lines @@
         }],
         ['enable_message_center==1', {
           'dependencies': [
             '../ui/message_center/message_center.gyp:message_center',
           ],
         }],
       ],
     },
   ],
 }