Fixes test runner command line

build/android/test_runner.py

 #!/usr/bin/env python
 #
 # Copyright 2013 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.
 
 """Runs all types of tests from one unified interface.
 
 TODO(gkanwar):
 * Add options to run Monkey tests.
@@ skipping 716 matching lines @@
       return '\nExample:\n  %s\n' % self.example
     return ''
 
 
 def main(argv):
   option_parser = CommandOptionParser(
       usage='Usage: %prog <command> [options]',
       command_list=VALID_COMMANDS.keys())
 
   if len(argv) < 2 or argv[1] not in VALID_COMMANDS:
+    # Parse args first, if this is '--help', optparse will display help and exit
+    option_parser.parse_args(argv)
     option_parser.error('Invalid command.')
   command = argv[1]
   VALID_COMMANDS[command].add_options_func(option_parser)
   options, args = option_parser.parse_args(argv)
   return VALID_COMMANDS[command].run_command_func(
       command, options, args, option_parser)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))