Adding the chrome://copresence page

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 1590 matching lines @@
       'browser/ui/website_settings/permission_menu_model.cc',
       'browser/ui/website_settings/permission_menu_model.h',
       'browser/ui/website_settings/website_settings_utils.cc',
       'browser/ui/website_settings/website_settings_utils.h',
       'browser/ui/webui/app_launcher_page_ui.cc',
       'browser/ui/webui/app_launcher_page_ui.h',
       'browser/ui/webui/bookmarks_ui.cc',
       'browser/ui/webui/bookmarks_ui.h',
       'browser/ui/webui/chrome_web_contents_handler.cc',
       'browser/ui/webui/chrome_web_contents_handler.h',
+      'browser/ui/webui/copresence_ui_handler.cc',
+      'browser/ui/webui/copresence_ui_handler.h',
+      'browser/ui/webui/copresence_ui.cc',
+      'browser/ui/webui/copresence_ui.h',
       'browser/ui/webui/devtools_ui.cc',
       'browser/ui/webui/devtools_ui.h',
       'browser/ui/webui/downloads_dom_handler.cc',
       'browser/ui/webui/downloads_dom_handler.h',
       'browser/ui/webui/downloads_ui.cc',
       'browser/ui/webui/downloads_ui.h',
       'browser/ui/webui/extensions/command_handler.cc',
       'browser/ui/webui/extensions/command_handler.h',
       'browser/ui/webui/extensions/extension_error_handler.cc',
       'browser/ui/webui/extensions/extension_error_handler.h',
@@ skipping 1523 matching lines @@
           ],
           'sources': [
             '<@(chrome_browser_ui_non_mobile_sources)',
             '<@(chrome_browser_ui_omnibox_non_mobile_sources)',
           ],
         }],
       ],
     },
   ],
 }