Disable ac charging similar to usb charging (used by Nexus6)

build/android/pylib/device/battery_utils.py

Index: build/android/pylib/device/battery_utils.py
diff --git a/build/android/pylib/device/battery_utils.py b/build/android/pylib/device/battery_utils.py
index cca89c725e6e1608b1d674ebfa319709af5ca6fa..bfe553d517b2aa3ddf57778f862f498021400709 100644
--- a/build/android/pylib/device/battery_utils.py
+++ b/build/android/pylib/device/battery_utils.py
@@ -238,7 +238,7 @@ class BatteryUtils(object):
       return self.GetCharging() is False
 
     self._device.RunShellCommand(
-        ['dumpsys', 'battery', 'set', 'usb', '1'], check_return=True)
+        ['dumpsys', 'battery', 'reset'], check_return=True)
     self._device.RunShellCommand(
         ['dumpsys', 'batterystats', '--reset'], check_return=True)
     battery_data = self._device.RunShellCommand(
@@ -252,6 +252,8 @@ class BatteryUtils(object):
           and l[PWI_POWER_INDEX] != 0):
         raise device_errors.CommandFailedError(
             'Non-zero pmi value found after reset.')
+    self._device.RunShellCommand(['dumpsys', 'battery', 'set', 'ac', '0'],
+                                 check_return=True)
     self._device.RunShellCommand(['dumpsys', 'battery', 'set', 'usb', '0'],
                                  check_return=True)
     timeout_retry.WaitFor(battery_updates_disabled, wait_period=1)
@@ -267,8 +269,6 @@ class BatteryUtils(object):
     def battery_updates_enabled():
       return self.GetCharging() is True
 
-    self._device.RunShellCommand(['dumpsys', 'battery', 'set', 'usb', '1'],

[rnephew (Wrong account), 2015/04/07 23:51:40]

This is in there because on K devices reset takes too long to run (30 seconds),
and telling it it is charging before it resets is a way around that. Instead of
deleting that line, I would recommend adding a line for setting ac to 1, or this
will break for K devices. 

[fmeawad, 2015/04/07 23:56:13]

I cannot set the ac to 1 as well as this will set the devices to have 2 power
sources (which is not the case after you do a reset, as it only picks one).
Will test it on a K and try to find a better solution as well as add comments as
pointed by john.

[fmeawad, 2015/04/08 00:54:29]

I checked the code, and this code is never called from a K device (it is guarded
by a check "dumpsys batterystats -c" and makes sure it is either revision 8 or 9
every where.
I have also tried manually on a K device and it seemed to take at most 5
seconds.
Given that we are deprecating most K devices, I think we can afford a  few
seconds on that platform for a clean solution. WDYT?

-                                 check_return=True)
     self._device.RunShellCommand(['dumpsys', 'battery', 'reset'],
                                  check_return=True)
     timeout_retry.WaitFor(battery_updates_enabled, wait_period=1)