Make package: work like Dart expects in preparation for a Sky SDK

mojo/tools/mojo_demo.py

 #!/usr/bin/env python
 # 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.
 
 from mopy.config import Config
 import argparse
 import mopy.paths
 import os
 import pipes
@@ skipping 18 matching lines @@
 
   config = Config(target_os=Config.OS_LINUX, is_debug=True)
   paths = mopy.paths.Paths(config, build_dir=args.build_dir)
   mojo_shell = paths.mojo_shell_path
 
   cmd = [mojo_shell]
   cmd.append('--v=1')
 
   HTTP_PORT = 9999
   configuration = 'Debug' if config.is_debug else 'Release'
-  server = SkyServer(HTTP_PORT, configuration, paths.src_root)
+  packages_root = os.path.join(paths.build_dir, 'gen')
+  server = SkyServer(HTTP_PORT, configuration, paths.src_root, packages_root)
 
   if args.demo == 'browser':
     base_url = server.path_as_url(paths.build_dir)
     wm_url = os.path.join(base_url, 'example_window_manager.mojo')
     browser_url = os.path.join(base_url, 'browser.mojo')
     cmd.append('--url-mappings=mojo:window_manager=mojo:example_window_manager')
     cmd.append('--args-for=mojo:window_manager %s' % (wm_url))
     cmd.append('--args-for=mojo:browser %s' % (browser_url))
     cmd.append('mojo:window_manager')
   elif args.demo == 'wm_flow':
@@ skipping 13 matching lines @@
 
   # http://stackoverflow.com/questions/4748344/whats-the-reverse-of-shlex-split
   # shlex.quote doesn't exist until 3.3
   # This doesn't print exactly what we want, but it's better than nothing:
   print " ".join(map(pipes.quote, cmd))
   with server:
     return subprocess.call(cmd)
 
 if __name__ == '__main__':
   sys.exit(main())