Add logging to debug battor not running

common/battor/battor/battor_wrapper.py

 # Copyright 2016 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 atexit
 import datetime
 import os
 import logging
 import platform
 import random
@@ skipping 19 matching lines @@
 def IsBattOrConnected(test_platform, android_device=None,
                       android_device_map=None, android_device_file=None):
   """Returns True if BattOr is detected."""
   if test_platform == 'android':
     if not android_device:
       raise ValueError('Must pass android device serial when determining '
                        'support on android platform')
 
     if not android_device_map:
       device_tree = find_usb_devices.GetBusNumberToDeviceTreeMap()
+      logging.warning('Device tree:', device_tree)
       if len(battor_device_mapping.GetBattOrList(device_tree)) == 1:
         return True
       if android_device_file:
         android_device_map = battor_device_mapping.ReadSerialMapFile(
             android_device_file)
       else:
         try:
           android_device_map = battor_device_mapping.GenerateSerialMap()
+          logging.warning('Android device map:', android_device_map)
         except battor_error.BattOrError:
+          logging.exception('Error generating serial map')
           return False
 
     # If neither if statement above is triggered, it means that an
     # android_device_map was passed in and will be used.
     return str(android_device) in android_device_map
 
   elif test_platform == 'win':
     for (_1, desc, _2) in serial.tools.list_ports.comports():
       if 'USB Serial Port' in desc:
         return True
@@ skipping 343 matching lines @@
     except subprocess.CalledProcessError as e:
       raise BattOrFlashError('BattOr flash failed with return code %s.'
                              % e.returncode)
 
     self._git_hash = None
     return True
 
 
 class BattOrFlashError(Exception):
   pass