Fix webpagereplay.py so that dns_port can be None.

chrome/test/functional/webpagereplay.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.
 
 """Start and stop Web Page Replay.
 
 Of the public module names, the following one is key:
   ReplayServer: a class to start/stop Web Page Replay.
 """
@@ skipping 76 matching lines @@
 
   def __init__(self, archive_path, replay_host, dns_port, http_port, https_port,
                replay_options=None, replay_dir=None,
                log_path=None):
     """Initialize ReplayServer.
 
     Args:
       archive_path: a path to a specific WPR archive (required).
       replay_host: the hostname to serve traffic.
       dns_port: an integer port on which to serve DNS traffic. May be zero
-          to let the OS choose an available port.
+          to let the OS choose an available port. If None DNS forwarding is
+          disabled.
       http_port: an integer port on which to serve HTTP traffic. May be zero
           to let the OS choose an available port.
       https_port: an integer port on which to serve HTTPS traffic. May be zero
           to let the OS choose an available port.
       replay_options: an iterable of options strings to forward to replay.py.
       replay_dir: directory that has replay.py and related modules.
       log_path: a path to a log file.
     """
     self.archive_path = os.environ.get('WPR_ARCHIVE_PATH', archive_path)
     self.replay_options = list(replay_options or ())
@@ skipping 18 matching lines @@
     self._CheckPath('replay script', self.replay_py)
 
     self.log_fh = None
     self.replay_process = None
 
   def _AddDefaultReplayOptions(self):
     """Set WPR command-line options. Can be overridden if needed."""
     self.replay_options = [
         '--host', str(self._replay_host),
         '--port', str(self.http_port),
-        '--dns_port', str(self.dns_port),
         '--ssl_port', str(self.https_port),
         '--use_closest_match',
         '--no-dns_forwarding',
         '--log_level', 'warning'
         ] + self.replay_options
+    if self.dns_port is not None:
+      self.replay_options.extend(['--dns_port', str(self.dns_port)])
 
   def _CheckPath(self, label, path):
     if not os.path.exists(path):
       raise ReplayNotFoundError(label, path)
 
   def _OpenLogFile(self):
     log_dir = os.path.dirname(self.log_path)
     if not os.path.exists(log_dir):
       os.makedirs(log_dir)
     return open(self.log_path, 'w')
@@ skipping 92 matching lines @@
       self.log_fh.close()
 
   def __enter__(self):
     """Add support for with-statement."""
     self.StartServer()
     return self
 
   def __exit__(self, unused_exc_type, unused_exc_val, unused_exc_tb):
     """Add support for with-statement."""
     self.StopServer()