[Android] Detect if device is not charging properly.

build/android/devil/android/battery_utils.py

Index: build/android/devil/android/battery_utils.py
diff --git a/build/android/devil/android/battery_utils.py b/build/android/devil/android/battery_utils.py
index 10dc49a7b61e603ff6a8614206e946e89f5e27eb..e18eec154407237e9c708d4e2deeeffecc58c30f 100644
--- a/build/android/devil/android/battery_utils.py
+++ b/build/android/devil/android/battery_utils.py
@@ -116,6 +116,8 @@ _PWS_AGGREGATION_INDEX = _PWI_AGGREGATION_INDEX
 _PWI_POWER_CONSUMPTION_INDEX = 5
 _PWS_POWER_CONSUMPTION_INDEX = _PWI_POWER_CONSUMPTION_INDEX
 
+_MAX_CHARGE_ERROR = 10
+
 
 class BatteryUtils(object):
 
@@ -131,7 +133,6 @@ class BatteryUtils(object):
         default_retries: An integer containing the default number or times an
                          operation should be retried on failure if no explicit
                          value is provided.
-
       Raises:
         TypeError: If it is not passed a DeviceUtils instance.
     """
@@ -141,6 +142,8 @@ class BatteryUtils(object):
     self._cache = device.GetClientCache(self.__class__.__name__)
     self._default_timeout = default_timeout
     self._default_retries = default_retries
+    self._charge_failure_count = 0

[jbudorick, 2016/02/05 01:40:43]

These two variables are local to ChargeDeviceToLevel (though they aren't local
to a thread) and should be handled there.

[rnephew (Reviews Here), 2016/02/05 01:52:00]

Switched to dict so it can be handled locally.

+    self._last_charge_value = 0
 
   @decorators.WithTimeoutAndRetriesFromInstance()
   def SupportsFuelGauge(self, timeout=None, retries=None):
@@ -440,8 +443,11 @@ class BatteryUtils(object):
     Args:
       level: level of charge to wait for.
       wait_period: time in seconds to wait between checking.
+    Raises:
+      device_errors.DeviceChargingError: If error while charging is detected.
     """
     self.SetCharging(True)
+    self._charge_failure_count = 0
 
     def device_charged():
       battery_level = self.GetBatteryInfo().get('level')
@@ -451,6 +457,16 @@ class BatteryUtils(object):
       else:
         logging.info('current battery level: %s', battery_level)
         battery_level = int(battery_level)
+
+      # Use > so that it will not reset if charge is going down.
+      if battery_level > self._last_charge_value:
+        self._last_charge_value = battery_level
+        self._charge_failure_count = 0
+
+      self._charge_failure_count += 1
+      if (not battery_level >= level
+          and self._charge_failure_count >= _MAX_CHARGE_ERROR):
+        raise device_errors.DeviceChargingError('Device not charging properly.')
       return battery_level >= level
 
     timeout_retry.WaitFor(device_charged, wait_period=wait_period)