Support dev servers defined in a mojoconfig file.

mojo/devtools/common/mojo_test

 #!/usr/bin/env python
 # 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.
 
 """Test runner for Mojo application tests.
 
 TODO(vtl|msw): Add a way of specifying data dependencies.
 """
 
@@ skipping 41 matching lines @@
 
 def main():
   parser = argparse.ArgumentParser(
       formatter_class=argparse.RawDescriptionHelpFormatter,
       description=_DESCRIPTION)
   parser.add_argument("test_list_file", type=file,
                       help="a file listing apptests to run")
   shell_config.add_shell_arguments(parser)
 
   script_args, shell_args = parser.parse_known_args()
-  config = shell_config.get_shell_config(script_args)
 
   try:
+    config = shell_config.get_shell_config(script_args)
     shell, common_shell_args = shell_arguments.get_shell(config, shell_args)
-  except shell_arguments.ShellConfigurationException as e:
+  except shell_config.ShellConfigurationException as e:
     print e
     return 1
 
   target_os = "android" if script_args.android else "linux"
   test_list_globals = {"target_os": target_os}
   exec script_args.test_list_file in test_list_globals
   test_list = test_list_globals["tests"]
 
   succeeded = True
   for test_dict in test_list:
@@ skipping 24 matching lines @@
       print "Unrecognized test type in %r" % test_dict
 
     print "Succeeded" if apptest_result else "Failed"
     _logger.info("Completed: %s" % test_name)
     if not apptest_result:
       succeeded = False
   return 0 if succeeded else 1
 
 if __name__ == '__main__':
   sys.exit(main())