Small improvements to api.platforms.android.

appengine/swarming/swarming_bot/api/platforms/android_test.py

 #!/usr/bin/env python
 # Copyright 2015 The Swarming Authors. All rights reserved.
 # Use of this source code is governed by the Apache v2.0 license that can be
 # found in the LICENSE file.
 
 import logging
 import sys
 import unittest
 
 import test_env_platforms
 test_env_platforms.setup_test_env()
 
 import android
 
 
-class MockDevice(object):
+class MockDevice(android.Device):
   def __init__(self, cmds):
+    super(MockDevice, self).__init__(None, None)
     self._cmds = cmds[:]
 
   def shell(self, cmd):
     data = self._cmds.pop(0)
     assert data[0] == cmd, (data, cmd)
     return data[1], 0
 
 
 RAW_IMEI = """Result: Parcel(
   0x00000000: 00000000 0000000f 00350033 00320035 '........3.5.5.2.'
@@ skipping 50 matching lines @@
     self.assertTrue(signer.Sign('data to sign'))
 
 
 
 if __name__ == '__main__':
   if '-v' in sys.argv:
     unittest.TestCase.maxDiff = None
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.CRITICAL)
   unittest.main()