old_contents: #!/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.
  
  """This script is used by chrome_tests.gypi's js2webui action to maintain the
  argument lists and to generate inlinable tests.
  """
  
  import json
  import optparse
  import os
  import subprocess
  import sys
  import shutil
  
  
  def main ():
    parser = optparse.OptionParser()
    parser.set_usage(
        "%prog v8_shell mock.js test_api.js js2webui.js "
        "testtype inputfile inputrelfile cxxoutfile jsoutfile")
    parser.add_option('-v', '--verbose', action='store_true')
    parser.add_option('-n', '--impotent', action='store_true',
                      help="don't execute; just print (as if verbose)")
    parser.add_option('--deps_js', action="store",
                      help=("Path to deps.js for dependency resolution, " +
                            "optional."))
    (opts, args) = parser.parse_args()
  
    if len(args) != 9:
      parser.error('all arguments are required.')
    (v8_shell, mock_js, test_api, js2webui, test_type,
        inputfile, inputrelfile, cxxoutfile, jsoutfile) = args
    cmd = [v8_shell]
    icudatafile = os.path.join(os.path.dirname(v8_shell), 'icudtl.dat')
    if os.path.exists(icudatafile):
      cmd.extend(['--icu-data-file=%s' % icudatafile])
    arguments = [js2webui, inputfile, inputrelfile, opts.deps_js,
                 cxxoutfile, test_type]
    cmd.extend(['-e', "arguments=" + json.dumps(arguments), mock_js,
           test_api, js2webui])
    if opts.verbose or opts.impotent:
      print cmd
    if not opts.impotent:
      try:
        with open(cxxoutfile, 'w') as f:
          subprocess.check_call(cmd, stdin=subprocess.PIPE, stdout=f)
        shutil.copyfile(inputfile, jsoutfile)
      except Exception, ex:
        if os.path.exists(cxxoutfile):
          # The contents of the output file will include the error message.
          print open(cxxoutfile).read()
          os.remove(cxxoutfile)
        if os.path.exists(jsoutfile):
          os.remove(jsoutfile)
        raise
  
  
  if __name__ == '__main__':
   sys.exit(main())
  
new_contents: #!/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.
  
  """This script is used by chrome_tests.gypi's js2webui action to maintain the
  argument lists and to generate inlinable tests.
  """
  
  import json
  import optparse
  import os
  import subprocess
  import sys
  import shutil
  
  
  def main ():
    parser = optparse.OptionParser()
    parser.set_usage(
        "%prog v8_shell mock.js test_api.js js2webui.js "
        "testtype inputfile inputrelfile cxxoutfile jsoutfile")
    parser.add_option('-v', '--verbose', action='store_true')
    parser.add_option('-n', '--impotent', action='store_true',
                      help="don't execute; just print (as if verbose)")
    parser.add_option('--deps_js', action="store",
                      help=("Path to deps.js for dependency resolution, " +
                            "optional."))
    (opts, args) = parser.parse_args()
  
    if len(args) != 9:
      parser.error('all arguments are required.')
    (v8_shell, mock_js, test_api, js2webui, test_type,
        inputfile, inputrelfile, cxxoutfile, jsoutfile) = args
    cmd = [v8_shell]
    icudatafile = os.path.join(os.path.dirname(v8_shell), 'icudtl.dat')
    if os.path.exists(icudatafile):
      cmd.extend(['--icu-data-file=%s' % icudatafile])
    arguments = [js2webui, inputfile, inputrelfile, opts.deps_js,
                 cxxoutfile, test_type]
    cmd.extend(['-e', "arguments=" + json.dumps(arguments), mock_js,
           test_api, js2webui])
    if opts.verbose or opts.impotent:
      print cmd
    if not opts.impotent:
      try:
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, bufsize=0)
        out, err = p.communicate()
        if p.returncode:
          raise Exception('Failed to run d8', out, err)
        with open(cxxoutfile, 'wb') as f:
          f.write(out)
        shutil.copyfile(inputfile, jsoutfile)
      except Exception, ex:
        if os.path.exists(cxxoutfile):
          os.remove(cxxoutfile)
        if os.path.exists(jsoutfile):
          os.remove(jsoutfile)
        raise
  
  
  if __name__ == '__main__':
   sys.exit(main())
  
subject: Use subprocess.Popen to communicate with d8