[Android] Add known devices flag for host_info.

testing/scripts/common.py

 # Copyright 2014 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.
 
 import argparse
 import contextlib
 import json
 import os
 import subprocess
 import sys
@@ skipping 28 matching lines @@
   parser.add_argument('--properties', type=parse_json, default={})
   # Args contains per-invocation arguments that potentially change the
   # behavior of the script.
   parser.add_argument('--args', type=parse_json, default=[])
 
   parser.add_argument(
       '--use-src-side-runtest-py', action='store_true',
       help='Use the src-side copy of runtest.py, as opposed to the build-side '
            'one')
 
+  parser.add_argument('--known-devices-file',
+                       help='Path to list of known android devices on host. '
+                            'Only used for host_info.')
+
   subparsers = parser.add_subparsers()
 
   run_parser = subparsers.add_parser('run')
   run_parser.add_argument(
       '--output', type=argparse.FileType('w'), required=True)
   run_parser.add_argument('--filter-file', type=argparse.FileType('r'))
   run_parser.set_defaults(func=funcs['run'])
 
   run_parser = subparsers.add_parser('compile_targets')
   run_parser.add_argument(
@@ skipping 104 matching lines @@
       [sys.executable, script_to_run] + extra_args)
 
   with open(log_file) as f:
     failures = json.load(f)
   json.dump({
       'valid': integration_test_res == 0,
       'failures': failures,
   }, output)
 
   return integration_test_res