[Android] Add nexus 5 work around for letting battery cool

The nexus 5 has a problem where battery temperature only updates when
the battery charge level has changed.

BUG=512167, 522127

Review URL: https://codereview.chromium.org/1297423002

Cr-Commit-Position: refs/heads/master@{#344504}

2 files changed, 108 insertions, 0 deletions

diff --git a/build/android/pylib/device/battery_utils.py b/build/android/pylib/device/battery_utils.py
index 35bf6ce..1a8c9f5 100644
--- a/build/android/pylib/device/battery_utils.py
+++ b/build/android/pylib/device/battery_utils.py
@@ -434,6 +434,40 @@ class BatteryUtils(object):
     finally:
       self.EnableBatteryUpdates(timeout=timeout, retries=retries)
 
+  def _DischargeDevice(self, percent, wait_period=120):
+    """Disables charging and waits for device to discharge given amount
+
+    Args:
+      percent: level of charge to discharge.
+
+    Raises:
+      ValueError: If percent is not between 1 and 99.
+    """
+    battery_level = int(self.GetBatteryInfo().get('level'))
+    if not 0 < percent < 100:
+      raise ValueError('Discharge amount(%s) must be between 1 and 99'
+                       % percent)
+    if battery_level is None:
+      logging.warning('Unable to find current battery level. Cannot discharge.')
+      return
+    # Do not discharge if it would make battery level too low.
+    if percent >= battery_level - 10:
+      logging.warning('Battery is too low or discharge amount requested is too '
+                      'high. Cannot discharge phone %s percent.', percent)
+      return
+
+    self.SetCharging(False)
+    def device_discharged():
+      self.SetCharging(True)
+      current_level = int(self.GetBatteryInfo().get('level'))
+      logging.info('current battery level: %s', current_level)
+      if battery_level - current_level >= percent:
+        return True
+      self.SetCharging(False)
+      return False
+
+    timeout_retry.WaitFor(device_discharged, wait_period=wait_period)
+
   def ChargeDeviceToLevel(self, level, wait_period=60):
     """Enables charging and waits for device to be charged to given level.
 
@@ -462,6 +496,8 @@ class BatteryUtils(object):
       wait_period: time in seconds to wait between checking.
     """
     def cool_device():
+      if self._cache['profile']['name'] == 'Nexus 5':
+        self._DischargeDevice(1)
       temp = self.GetBatteryInfo().get('temperature')
       if temp is None:
         logging.warning('Unable to find current battery temperature.')
@@ -469,6 +505,8 @@ class BatteryUtils(object):
       else:
         logging.info('Current battery temperature: %s', temp)
       return int(temp) <= target_temp
+
+    self._DiscoverDeviceProfile()
     self.EnableBatteryUpdates()
     logging.info('Waiting for the device to cool down to %s (0.1 C)',
                  target_temp)
diff --git a/build/android/pylib/device/battery_utils_test.py b/build/android/pylib/device/battery_utils_test.py
index 2063efa..ff961e7 100755
--- a/build/android/pylib/device/battery_utils_test.py
+++ b/build/android/pylib/device/battery_utils_test.py
@@ -269,6 +269,62 @@ class BatteryUtilsChargeDevice(BatteryUtilsTest):
       self.battery.ChargeDeviceToLevel(95)
 
 
+class BatteryUtilsDischargeDevice(BatteryUtilsTest):
+
+  @mock.patch('time.sleep', mock.Mock())
+  def testDischargeDevice_exact(self):
+    with self.assertCalls(
+        (self.call.battery.GetBatteryInfo(), {'level': '100'}),
+        (self.call.battery.SetCharging(False)),
+        (self.call.battery.SetCharging(True)),
+        (self.call.battery.GetBatteryInfo(), {'level': '99'})):
+      self.battery._DischargeDevice(1)
+
+  @mock.patch('time.sleep', mock.Mock())
+  def testDischargeDevice_over(self):
+    with self.assertCalls(
+        (self.call.battery.GetBatteryInfo(), {'level': '100'}),
+        (self.call.battery.SetCharging(False)),
+        (self.call.battery.SetCharging(True)),
+        (self.call.battery.GetBatteryInfo(), {'level': '50'})):
+      self.battery._DischargeDevice(1)
+
+  @mock.patch('time.sleep', mock.Mock())
+  def testDischargeDevice_takeslong(self):
+    with self.assertCalls(
+        (self.call.battery.GetBatteryInfo(), {'level': '100'}),
+        (self.call.battery.SetCharging(False)),
+        (self.call.battery.SetCharging(True)),
+        (self.call.battery.GetBatteryInfo(), {'level': '100'}),
+        (self.call.battery.SetCharging(False)),
+        (self.call.battery.SetCharging(True)),
+        (self.call.battery.GetBatteryInfo(), {'level': '99'}),
+        (self.call.battery.SetCharging(False)),
+        (self.call.battery.SetCharging(True)),
+        (self.call.battery.GetBatteryInfo(), {'level': '98'}),
+        (self.call.battery.SetCharging(False)),
+        (self.call.battery.SetCharging(True)),
+        (self.call.battery.GetBatteryInfo(), {'level': '97'})):
+      self.battery._DischargeDevice(3)
+
+  @mock.patch('time.sleep', mock.Mock())
+  def testDischargeDevice_dischargeTooClose(self):
+    with self.assertCalls(
+        (self.call.battery.GetBatteryInfo(), {'level': '100'})):
+      self.battery._DischargeDevice(99)
+
+  @mock.patch('time.sleep', mock.Mock())
+  def testDischargeDevice_percentageOutOfBounds(self):
+    with self.assertCalls(
+        (self.call.battery.GetBatteryInfo(), {'level': '100'})):
+      with self.assertRaises(ValueError):
+          self.battery._DischargeDevice(100)
+    with self.assertCalls(
+        (self.call.battery.GetBatteryInfo(), {'level': '100'})):
+      with self.assertRaises(ValueError):
+          self.battery._DischargeDevice(0)
+
+
 class BatteryUtilsGetBatteryInfoTest(BatteryUtilsTest):
 
   def testGetBatteryInfo_normal(self):
@@ -381,6 +437,7 @@ class BatteryUtilsLetBatteryCoolToTemperatureTest(BatteryUtilsTest):
 
   @mock.patch('time.sleep', mock.Mock())
   def testLetBatteryCoolToTemperature_startUnder(self):
+    self.battery._cache['profile'] = self._NEXUS_6
     with self.assertCalls(
         (self.call.battery.EnableBatteryUpdates(), []),
         (self.call.battery.GetBatteryInfo(), {'temperature': '500'})):
@@ -388,12 +445,25 @@ class BatteryUtilsLetBatteryCoolToTemperatureTest(BatteryUtilsTest):
 
   @mock.patch('time.sleep', mock.Mock())
   def testLetBatteryCoolToTemperature_startOver(self):
+    self.battery._cache['profile'] = self._NEXUS_6
     with self.assertCalls(
         (self.call.battery.EnableBatteryUpdates(), []),
         (self.call.battery.GetBatteryInfo(), {'temperature': '500'}),
         (self.call.battery.GetBatteryInfo(), {'temperature': '400'})):
       self.battery.LetBatteryCoolToTemperature(400)
 
+  @mock.patch('time.sleep', mock.Mock())
+  def testLetBatteryCoolToTemperature_nexus5(self):
+    self.battery._cache['profile'] = self._NEXUS_5
+    with self.assertCalls(
+        (self.call.battery.EnableBatteryUpdates(), []),
+        (self.call.battery._DischargeDevice(1), []),
+        (self.call.battery.GetBatteryInfo(), {'temperature': '500'}),
+        (self.call.battery._DischargeDevice(1), []),
+        (self.call.battery.GetBatteryInfo(), {'temperature': '400'})):
+      self.battery.LetBatteryCoolToTemperature(400)
+
+
 class BatteryUtilsSupportsFuelGaugeTest(BatteryUtilsTest):
 
   def testSupportsFuelGauge_false(self):