Show MessageWindow from the background page

remoting/remoting_webapp_files.gypi

 # Copyright 2014 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': {
     'remoting_webapp_info_files': [
       'resources/chromoting16.webp',
       'resources/chromoting48.webp',
       'resources/chromoting128.webp',
@@ skipping 179 matching lines @@
       'webapp/host_installer.js',
       'webapp/host_session.js',
       'webapp/it2me_host_facade.js',
       'webapp/plugin_settings.js',
       'webapp/typecheck.js',
       'webapp/background/app_launcher.js',
       'webapp/background/background.js',
       'webapp/background/it2me_helpee_channel.js',
       'webapp/background/it2me_helper_channel.js',
       'webapp/background/it2me_service.js',
+      'webapp/background/message_window_helper.js',
+      'webapp/background/message_window_manager.js',
     ],
 
     # The JavaScript files required by wcs_sandbox.html.
     'remoting_webapp_wcs_sandbox_html_js_files': [
       '<@(remoting_webapp_js_wcs_sandbox_files)',
       'webapp/error.js',
       'webapp/plugin_settings.js',
     ],
 
     # All the JavaScript files required by the webapp.
     'remoting_webapp_all_js_files': [
       # JS files for main.html.
       '<@(remoting_webapp_main_html_js_files)',
       '<@(remoting_webapp_background_js_files)',
+      # JS files for message_window.html
+      'webapp/background/message_window.js',
       # JS files for wcs_sandbox.html.
       # Use r_w_js_wcs_sandbox_files instead of r_w_wcs_sandbox_html_js_files
       # so that we don't double include error.js and plugin_settings.js.
       '<@(remoting_webapp_js_wcs_sandbox_files)',
       # JS files referenced in mainfest.json.
       '<@(remoting_webapp_js_auth_v1_files)',
     ],
 
     'remoting_webapp_resource_files': [
       'resources/disclosure_arrow_down.webp',
       'resources/disclosure_arrow_right.webp',
       'resources/drag.webp',
       'resources/host_setup_instructions.webp',
       'resources/icon_close.webp',
       'resources/icon_cross.webp',
       'resources/icon_disconnect.webp',
       'resources/icon_help.webp',
       'resources/icon_host.webp',
       'resources/icon_maximize_restore.webp',
       'resources/icon_minimize.webp',
       'resources/icon_options.webp',
       'resources/icon_pencil.webp',
       'resources/icon_warning.webp',
       'resources/infographic_my_computers.webp',
       'resources/infographic_remote_assistance.webp',
       'resources/plus.webp',
       'resources/reload.webp',
       'resources/tick.webp',
       'webapp/connection_stats.css',
+      'webapp/html/message_window.html',
       'webapp/main.css',
       'webapp/menu_button.css',
+      'webapp/message_window.css',
       'webapp/open_sans.css',
       'webapp/open_sans.woff',
       'webapp/scale-to-fit.webp',
       'webapp/spinner.gif',
       'webapp/toolbar.css',
       'webapp/window_frame.css',
     ],
 
     'remoting_webapp_files': [
       '<@(remoting_webapp_info_files)',
@@ skipping 31 matching lines @@
       'webapp/html/dialog_token_refresh_failed.html',
       'webapp/html/toolbar.html',
       'webapp/html/ui_header.html',
       'webapp/html/ui_it2me.html',
       'webapp/html/ui_me2me.html',
       'webapp/html/window_frame.html',
     ],
 
   },
 }