Implement host settings migration.

remoting/webapp/files.gni

 # Copyright 2015 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.
 
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@@ skipping 405 matching lines @@
 #
 
 remoting_webapp_template_background = "crd/html/template_background.html"
 
 # These JS files are specific to the background page and are not part of
 # the main JS files.
 remoting_webapp_background_html_js_files = [
   "crd/js/activation_handler.js",
   "crd/js/app_launcher.js",
   "crd/js/background.js",
+  "crd/js/options_export.js",
 ]
 
 # All the JavaScript files required by background.html.
 remoting_webapp_background_html_all_js_files =
     remoting_webapp_background_html_js_files
 remoting_webapp_background_html_all_js_files += [
   "base/js/base.js",
   "base/js/chromoting_event.js",
   "base/js/error.js",
   "base/js/identity.js",
@@ skipping 127 matching lines @@
       "webapp/crd/manifest.json.jinja2",
       remoting_webapp_template_background,
       remoting_webapp_template_main,
       remoting_webapp_template_message_window,
       remoting_webapp_template_wcs_sandbox,
     ] + remoting_webapp_template_files + remoting_webapp_crd_js_files
 
 webapp_js_files = remoting_webapp_unittest_html_all_js_files +
                   remoting_webapp_wcs_sandbox_html_js_files +
                   remoting_webapp_background_html_js_files