[Chromoting] Add GN build support for ar_sample_app target.

remoting/app_remoting_webapp_build.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.
 
 {
   'includes': [
     'remoting_version.gypi',
     'remoting_locales.gypi',
     'remoting_options.gypi',
     'remoting_webapp_files.gypi',
     'app_remoting_webapp_files.gypi',
   ],
 
+  # GN version: See remoting/webapp/build_template.gni
   'target_defaults': {
     'type': 'none',
 
     'dependencies': [
       # TODO(wez): Create proper resources for shared-stub and app-specific
       # stubs.
       '<(DEPTH)/remoting/remoting.gyp:remoting_resources',
     ],
 
     'locale_files': [
@@ skipping 88 matching lines @@
         ],
         'action': [
           'python', '<(DEPTH)/remoting/webapp/build-webapp.py',
           '<(buildtype)',
           '<(version_full)',
           '<(output_dir)',
           '<(zip_path)',
           '<(ar_app_manifest_app)', # Manifest template
           'app_remoting',  # Web app type
           '<@(ar_webapp_files)',
-          '<@(ar_generated_html_files)',
           '--locales_listfile',
           '<(ar_webapp_locales_listfile)',
           '--jinja_paths',
           '<(DEPTH)/remoting/webapp/app_remoting',
           '<@(remoting_app_id)',
           '--app_name',
           '<(remoting_app_name)',
           '--app_description',
           '<(remoting_app_description)',
           '--app_capabilities',
@@ skipping 108 matching lines @@
         # rather than using the extension id.
         # This is only done for Dev apps because the app-id for Release apps
         # *must* match the extension id.
         'variables': {
           'remoting_app_id': ['--appid', '>(_app_id)'],
         },
       }],
     ],  # conditions
   },  # target_defaults
 }