Put screenshot.py back to work

build/android/screenshot.py

 #!/usr/bin/env python
 
 # Copyright (c) 2012 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.
 
 """Takes a screenshot or a screen video capture from an Android device."""
 
 import logging
 import optparse
@@ skipping 54 matching lines @@
   parser.add_option_group(video_options)
 
   (options, args) = parser.parse_args()
 
   if options.verbose:
     logging.getLogger().setLevel(logging.DEBUG)
 
   if not options.device and len(android_commands.GetAttachedDevices()) > 1:
     parser.error('Multiple devices are attached. '
                  'Please specify device serial number with --device.')
+  elif not options.device and len(android_commands.GetAttachedDevices()) == 1:

[jbudorick, 2014/12/16 02:18:51]

Couple of problems in here:
 - We're no longer using android_commands in new code. adb_wrapper.GetDevices()
from b/a/pylib/device/adb_wrapper.py is what you're looking for.
 - No need to call that 3 times -- just call it once and store the result.

[Ian Wen, 2014/12/16 18:11:52]

Did a small improvement by storing it locally. However it seems
adb_wrapper.GetDevices() is not a static method; it needs to initialize
AdbWrapper instance, which takes device number as arguments.

+    options.device = android_commands.GetAttachedDevices()[0]
 
   if len(args) > 1:
     parser.error('Too many positional arguments.')
   host_file = args[0] if args else options.file
   device = device_utils.DeviceUtils(options.device)
 
   if options.video:
     _CaptureVideo(device, host_file, options)
   else:
     _CaptureScreenshot(device, host_file)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())