MD Settings: break SettingsPageUIHandler to its own file

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.
 
 {
   'variables': {
     # There are two sections of sources:
     # * "Platform"-based sources (OS, toolkit, etc.)
     # * Feature/directory-based sources (e.g., history, printing)
 
@@ skipping 2013 matching lines @@
       'browser/ui/webui/settings/people_handler.cc',
       'browser/ui/webui/settings/people_handler.h',
       'browser/ui/webui/settings/reset_settings_handler.cc',
       'browser/ui/webui/settings/reset_settings_handler.h',
       'browser/ui/webui/settings/search_engines_handler.cc',
       'browser/ui/webui/settings/search_engines_handler.h',
       'browser/ui/webui/settings/settings_clear_browsing_data_handler.cc',
       'browser/ui/webui/settings/settings_clear_browsing_data_handler.h',
       'browser/ui/webui/settings/settings_manage_profile_handler.cc',
       'browser/ui/webui/settings/settings_manage_profile_handler.h',
+      'browser/ui/webui/settings/settings_page_ui_handler.cc',
+      'browser/ui/webui/settings/settings_page_ui_handler.h',
       'browser/ui/webui/settings/settings_startup_pages_handler.cc',
       'browser/ui/webui/settings/settings_startup_pages_handler.h',
       'browser/ui/webui/settings/site_settings_handler.cc',
       'browser/ui/webui/settings/site_settings_handler.h',
       'browser/ui/webui/settings/system_handler.cc',
       'browser/ui/webui/settings/system_handler.h',
       'browser/ui/webui/signin/get_auth_frame.cc',
       'browser/ui/webui/signin/get_auth_frame.h',
       'browser/ui/webui/signin/login_ui_service.cc',
       'browser/ui/webui/signin/login_ui_service.h',
@@ skipping 1322 matching lines @@
           ],
           'sources': [
             '<@(chrome_browser_ui_non_mobile_sources)',
             '<@(chrome_browser_ui_omnibox_non_mobile_sources)',
           ],
         }],
       ],
     },
   ],
 }