Allow to set a fixed port for the development server.

mojo/devtools/common/devtoolslib/shell_config.py

 # Copyright 2015 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.
 
 """Configuration for the shell abstraction.
 
 This module declares ShellConfig and knows how to compute it from command-line
 arguments, applying any default paths inferred from the checkout, configuration
 file, etc.
 """
@@ skipping 30 matching lines @@
     # Desktop-only.
     self.use_osmesa = None
 
 
 class DevServerConfig(object):
   """Configuration for a development server running on a host and available to
   the shell.
   """
   def __init__(self):
     self.host = None
+    self.port = None
     self.mappings = None
 
 
 def add_shell_arguments(parser):
   """Adds argparse arguments allowing to configure shell abstraction using
   configure_shell() below.
   """
   # Arguments configuring the shell run.
   parser.add_argument('--android', help='Run on Android',
                       action='store_true')
@@ skipping 125 matching lines @@
         config = _read_config_file(config_file, config_file_aliases)
       except SyntaxError:
         raise ShellConfigurationException('Failed to parse the mojoconfig '
                                           'file.')
 
     if 'dev_servers' in config:
       try:
         for dev_server_spec in config['dev_servers']:
           dev_server_config = DevServerConfig()
           dev_server_config.host = dev_server_spec['host']
+          dev_server_config.port = dev_server_spec.get('port', None)
           dev_server_config.mappings = []
           for prefix, path in dev_server_spec['mappings']:
             dev_server_config.mappings.append((prefix, path))
           shell_config.dev_servers.append(dev_server_config)
       except (ValueError, KeyError):
         raise ShellConfigurationException('Failed to parse dev_servers in '
                                           'the config file.')
 
     if 'content_handlers' in config:
       try:
         for (mime_type,
              content_handler_url) in config['content_handlers'].iteritems():
           shell_config.content_handlers[mime_type] = content_handler_url
       except (ValueError, KeyError):
         raise ShellConfigurationException('Failed to parse content_handlers in '
                                           'the config file.')
   return shell_config