[Chromoting] Add GN build support for ar_sample_app target.

remoting/webapp/build-webapp.py

 #!/usr/bin/env python
 # Copyright (c) 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.
 
 """Creates a directory with with the unpacked contents of the remoting webapp.
 
 The directory will contain a copy-of or a link-to to all remoting webapp
 resources.  This includes HTML/JS and any plugin binaries. The script also
 massages resulting files appropriately with host plugin data. Finally,
@@ skipping 151 matching lines @@
         files.append(s.rstrip())
 
   # Ensure a fresh directory.
   try:
     shutil.rmtree(destination)
   except OSError:
     if os.path.exists(destination):
       raise
     else:
       pass
-  os.mkdir(destination, 0775)
+  os.makedirs(destination, 0775)
 
   if buildtype != 'Official' and buildtype != 'Release' and buildtype != 'Dev':
     raise Exception('Unknown buildtype: ' + buildtype)
 
   jinja_context = {
     'webapp_type': webapp_type,
     'buildtype': buildtype,
   }
 
   # Copy all the files.
@@ skipping 273 matching lines @@
   parser.add_argument('--use_gcd', choices=['0', '1'], default='0')
 
   args = parser.parse_args()
   args.use_gcd = (args.use_gcd != '0')
   args.app_capabilities = set(args.app_capabilities)
   return buildWebApp(**vars(args))
 
 
 if __name__ == '__main__':
   sys.exit(main())