new_contents: #!/usr/bin/env python
  #
  # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
  # for details. All rights reserved. Use of this source code is governed by a
  # BSD-style license that can be found in the LICENSE file.
  #
  
  import optparse
  import shutil
  import sys
  import utils
  
  HOST_OS = utils.GuessOS()
  
  def BuildOptions():
    result = optparse.OptionParser()
    result.add_option("-m", "--mode",
        help='Build variants (comma-separated).',
        metavar='[all,debug,release]',
        default='debug')
    result.add_option("--arch",
        help='Target architectures (comma-separated).',
        metavar='[all,ia32,x64,simarm,arm]',
        default=utils.GuessArchitecture())
    return result
  
  def ProcessOptions(options):
    if options.arch == 'all':
      options.arch = 'ia32,x64'
    if options.mode == 'all':
      options.mode = 'release,debug'
    options.mode = options.mode.split(',')
    options.arch = options.arch.split(',')
    for mode in options.mode:
      if not mode in ['debug', 'release']:
        print "Unknown mode %s" % mode
        return False
    for arch in options.arch:
      if not arch in ['ia32', 'x64', 'simarm', 'arm']:
        print "Unknown arch %s" % arch
        return False
    return True
  
  def Main():
    parser = BuildOptions()
    (options, args) = parser.parse_args()
    if not ProcessOptions(options):
      parser.print_help()
      return 1
  
    # Delete the output for the targets for each requested configuration.
    for mode in options.mode:
      for arch in options.arch:
        build_root = utils.GetBuildRoot(HOST_OS, mode=mode, arch=arch)
        print "Deleting %s" % (build_root)
        shutil.rmtree(build_root, ignore_errors=True)
    return 0
  
  if __name__ == '__main__':
    sys.exit(Main())
  
subject: Add python script for clobbering the output directory of a build on any platform given the mode and architecture. Review URL: https://chromiumcodereview.appspot.com//10830302