Add new method to disable android device charging.

build/android/pylib/device/device_utils.py

Index: build/android/pylib/device/device_utils.py
diff --git a/build/android/pylib/device/device_utils.py b/build/android/pylib/device/device_utils.py
index b6fd7323bb9a3c71e566049719a963bba2ce9023..a988e8df476bf1d72852fae32d12de2fdee3ff69 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -69,6 +69,11 @@ _CONTROL_CHARGING_COMMANDS = [
   },
 ]
 
+_DEFAULT_CHARGING_COMMANDS = {
+    'witness_file': None,
+    'enable_command': 'dumpsys battery reset',
+    'disable_command': 'dumpsys battery set usb 0',
+}
 
 @decorators.WithExplicitTimeoutAndRetries(
     _DEFAULT_TIMEOUT, _DEFAULT_RETRIES)
@@ -1414,8 +1419,17 @@ class DeviceUtils(object):
     # Skip the first line, which is just a header.
     for line in self.RunShellCommand(
         ['dumpsys', 'battery'], check_return=True)[1:]:
-      k, v = line.split(': ', 1)
-      result[k.strip()] = v.strip()
+      # If usb charging has been disabled, an extra line of header exists.
+      # If usb charging has been disabled, an extra line of header exists.

[klundberg, 2015/03/11 14:27:14]

I'm seeing double :-)

Please remove one of the comments.

[rnephew (Wrong account), 2015/03/11 18:27:01]

Done.

+      if 'UPDATES STOPPED' in line:
+        logging.warning('Dumpsys battery not recieving updates. '

[klundberg, 2015/03/11 14:27:14]

s/recieving/receiving

[rnephew (Wrong account), 2015/03/11 18:27:01]

Done.

+                        'Run dumpsys battery reset if this is in error.')
+      elif ':' not in line:
+        logging.warning('Unknown line found in dumpsys battery.')
+        logging.warning(line)
+      else:
+        k, v = line.split(': ', 1)
+        result[k.strip()] = v.strip()
     return result
 
   @decorators.WithTimeoutAndRetriesFromInstance()
@@ -1451,8 +1465,9 @@ class DeviceUtils(object):
           self._cache['charging_config'] = c
           break
       else:
-        raise device_errors.CommandFailedError(
-            'Unable to find charging commands.')
+        logging.warning('No charging information found.'
+                        'Defaulting to generic values.')
+        self._cache['charging_config'] = _DEFAULT_CHARGING_COMMANDS
 
     if enabled:
       command = self._cache['charging_config']['enable_command']