[Android][Telemetry] Seperate fuel gauge from AndroidDumpsysPowerMonitor

tools/telemetry/telemetry/internal/platform/power_monitor/android_fuelgauge_power_monitor.py

Index: tools/telemetry/telemetry/internal/platform/power_monitor/android_fuelgauge_power_monitor.py
diff --git a/tools/telemetry/telemetry/internal/platform/power_monitor/android_fuelgauge_power_monitor.py b/tools/telemetry/telemetry/internal/platform/power_monitor/android_fuelgauge_power_monitor.py
new file mode 100644
index 0000000000000000000000000000000000000000..653bcf383c8c6e074795125c652ed3ba54d791fc
--- /dev/null
+++ b/tools/telemetry/telemetry/internal/platform/power_monitor/android_fuelgauge_power_monitor.py
@@ -0,0 +1,55 @@
+# Copyright 2014 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 logging
+
+from telemetry.internal.platform import power_monitor
+
+
+class FuelGaugePowerMonitor(power_monitor.PowerMonitor):
+  """PowerMonitor that relies on the fuel gauge chips to monitor the power
+  consumption of a android device.
+  """
+  def __init__(self, battery, platform_backend):
+    """Constructor.
+
+    Args:
+        battery: A BatteryUtil instance.
+        platform_backend: A LinuxBasedPlatformBackend instance.
+    """
+    super(FuelGaugePowerMonitor, self).__init__()
+    self._battery = battery
+    self._starting_fuel_gauge = None
+
+  def CanMonitorPower(self):
+    return self._battery.SupportsFuelGauge()
+
+  def StartMonitoringPower(self, browser):
+    self._battery.TieredSetCharging(False)
+    self._starting_fuel_gauge = self._battery.GetFuelGaugeChargeCounter()
+
+  def StopMonitoringPower(self):
+    # Convert from nAh to mAh.
+    fuel_gauge_delta = (
+        float((self._starting_fuel_gauge) -
+        self._battery.GetFuelGaugeChargeCounter()) / 1000000)
+    self._battery.TieredSetCharging(True)
+
+    voltage = self._battery.GetBatteryInfo().get('voltage')
+    if voltage is None:
+      # Converting at a nominal voltage of 4.0V, as those values are obtained by
+      # a heuristic, and 4.0V is the voltage we set when using a monsoon device.
+      voltage = 4.0
+      logging.warning('Unable to get device voltage. Using %s.', voltage)
+    else:
+      voltage = float(voltage) / 1000
+
+    return self.ProcessPowerData(voltage, fuel_gauge_delta)
+
+  @staticmethod
+  def ProcessPowerData(voltage, fuel_gauge_delta):
+    power_results = {'identifier': 'fuel_gauge'}
+    power_results['fuel_gauge_energy_consumption_mwh'] = (
+        fuel_gauge_delta * voltage)
+    return power_results