Flunk the build if no Android devices are online.

build/android/device_status_check.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.
 
 """A class to keep track of devices across builds and report state."""
 import logging
 import optparse
 import os
@@ skipping 165 matching lines @@
   for serial, dev_errors in zip(devices, errors):
     if dev_errors:
       err_msg += ['%s errors:' % serial]
       err_msg += ['    %s' % error for error in dev_errors]
 
   if err_msg:
     buildbot_report.PrintWarning()
     msg = '\n'.join(err_msg)
     print msg
     SendDeviceStatusAlert(msg)
+
+  if not devices:
     return 1
 
 
 if __name__ == '__main__':
   sys.exit(main())