[Android] Reland of b/a/test_runner.py optparse to argparse switch.

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."""
 
 import argparse
 import collections
@@ skipping 123 matching lines @@
                            'to run on.'))
 
 
 def AddGTestOptions(parser):
   """Adds gtest options to |parser|."""
 
   gtest_suites = list(gtest_config.STABLE_TEST_SUITES
                       + gtest_config.EXPERIMENTAL_TEST_SUITES)
 
   group = parser.add_argument_group('GTest Options')
-  group.add_argument('-s', '--suite', dest='suite_name', choices=gtest_suites,
+  group.add_argument('-s', '--suite', dest='suite_name',
                      nargs='+', metavar='SUITE_NAME', required=True,
-                     help=('Executable name of the test suite to run.'))
+                     help=('Executable name of the test suite to run. '
+                           'Available suites include (but are not limited to): '
+                            '%s' % ', '.join('"%s"' % s for s in gtest_suites)))
   group.add_argument('-f', '--gtest_filter', '--gtest-filter',
                      dest='test_filter',
                      help='googletest-style filter string.')
   group.add_argument('--gtest_also_run_disabled_tests',
                      '--gtest-also-run-disabled-tests',
                      dest='run_disabled', action='store_true',
                      help='Also run disabled tests if applicable.')
   group.add_argument('-a', '--test-arguments', dest='test_arguments',
                      default='',
                      help='Additional arguments to pass to the test.')
@@ skipping 758 matching lines @@
   command_parsers = parser.add_subparsers(title='test types',
                                           dest='command')
 
   for test_type, config in sorted(VALID_COMMANDS.iteritems(),
                                   key=lambda x: x[0]):
     subparser = command_parsers.add_parser(
         test_type, usage='%(prog)s [options]', help=config.help_txt)
     config.add_options_func(subparser)
 
   args = parser.parse_args()
-  RunTestsCommand(args, parser)
-
-  return 0
+  return RunTestsCommand(args, parser)
 
 
 if __name__ == '__main__':
   sys.exit(main())