Android test_runner.py: Add --enable-device-cache to speed up file pushing

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 168 matching lines @@
   """Adds device options to |parser|."""
   group = parser.add_argument_group(title='Device Options')
   group.add_argument('--tool',
                      dest='tool',
                      help=('Run the test under a tool '
                            '(use --tool help to list them)'))
   group.add_argument('-d', '--device', dest='test_device',
                      help=('Target device for the test suite '
                            'to run on.'))
   group.add_argument('--blacklist-file', help='Device blacklist file.')
+  group.add_argument('--enable-device-cache', action='store_true',
+                     help='Cache device state to disk between runs')
 
 
 def AddGTestOptions(parser):
   """Adds gtest options to |parser|."""
 
   group = parser.add_argument_group('GTest Options')
   group.add_argument('-s', '--suite', dest='suite_name',
                      nargs='+', metavar='SUITE_NAME', required=True,
                      help='Executable name of the test suite to run.')
   group.add_argument('--gtest_also_run_disabled_tests',
@@ skipping 661 matching lines @@
   try:
     suite = unittest.TestSuite()
     suite.addTests(unittest.defaultTestLoader.loadTestsFromName(m)
                    for m in suite_test_modules)
     runner = unittest.TextTestRunner(verbosity=1+args.verbose_count)
     return 0 if runner.run(suite).wasSuccessful() else 1
   finally:
     sys.path = sys.path[1:]
 
 
-def _GetAttachedDevices(blacklist_file, test_device):
+def _GetAttachedDevices(blacklist_file, test_device, enable_cache):
   """Get all attached devices.
 
   Args:
+    blacklist_file: Path to device blacklist.
     test_device: Name of a specific device to use.
+    enable_cache: Whether to enable checksum caching.
 
   Returns:
     A list of attached devices.
   """
   blacklist = (device_blacklist.Blacklist(blacklist_file)
                if blacklist_file
                else None)
 
-  attached_devices = device_utils.DeviceUtils.HealthyDevices(blacklist)
+  attached_devices = device_utils.DeviceUtils.HealthyDevices(
+      blacklist, enable_device_files_cache=enable_cache)
   if test_device:
     test_device = [d for d in attached_devices if d == test_device]
     if not test_device:
       raise device_errors.DeviceUnreachableError(
           'Did not find device %s among attached device. Attached devices: %s'
           % (test_device, ', '.join(attached_devices)))
     return test_device
 
   else:
     if not attached_devices:
@@ skipping 18 matching lines @@
   command = args.command
 
   ProcessCommonOptions(args)
 
   if args.enable_platform_mode:
     return RunTestsInPlatformMode(args, parser)
 
   if command in constants.LOCAL_MACHINE_TESTS:
     devices = []
   else:
-    devices = _GetAttachedDevices(args.blacklist_file, args.test_device)
+    devices = _GetAttachedDevices(args.blacklist_file, args.test_device,
+                                  args.enable_device_cache)
 
   forwarder.Forwarder.RemoveHostLog()
   if not ports.ResetTestServerPortAllocation():
     raise Exception('Failed to reset test server port.')
 
   if command == 'gtest':
     return RunTestsInPlatformMode(args, parser)
   elif command == 'linker':
     return _RunLinkerTests(args, devices)
   elif command == 'instrumentation':
@@ skipping 117 matching lines @@
     if e.is_infra_error:
       return constants.INFRA_EXIT_CODE
     return constants.ERROR_EXIT_CODE
   except: # pylint: disable=W0702
     logging.exception('Unrecognized error occurred.')
     return constants.ERROR_EXIT_CODE
 
 
 if __name__ == '__main__':
   sys.exit(main())