[android] Create Battery Utils to seperate power functionality

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 9f538e1b0efd9f51ffaa4c1345febe8149edccc6..34ae2efb4ae5320d9bb3c2913b57094f99024ff9 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -1438,6 +1438,7 @@ class DeviceUtils(object):
     """
     return logcat_monitor.LogcatMonitor(self.adb, *args, **kwargs)
 
+  # TODO(rnephew): Remove when battery_utils is switched to.
   @decorators.WithTimeoutAndRetriesFromInstance()
   def GetBatteryInfo(self, timeout=None, retries=None):
     """Gets battery info for the device.
@@ -1465,6 +1466,7 @@ class DeviceUtils(object):
         result[k.strip()] = v.strip()
     return result
 
+  # TODO(rnephew): Remove when battery_utils is switched to.
   @decorators.WithTimeoutAndRetriesFromInstance()
   def GetCharging(self, timeout=None, retries=None):
     """Gets the charging state of the device.
@@ -1482,6 +1484,7 @@ class DeviceUtils(object):
         return True
     return False
 
+  # TODO(rnephew): Remove when battery_utils is switched to.
   @decorators.WithTimeoutAndRetriesFromInstance()
   def SetCharging(self, enabled, timeout=None, retries=None):
     """Enables or disables charging on the device.
@@ -1512,7 +1515,7 @@ class DeviceUtils(object):
 
     timeout_retry.WaitFor(set_and_verify_charging, wait_period=1)
 
-  # TODO(rnephew): Make private when all use cases can use the context manager.
+  # TODO(rnephew): Remove when battery_utils is switched to.
   @decorators.WithTimeoutAndRetriesFromInstance()
   def DisableBatteryUpdates(self, timeout=None, retries=None):
     """ Resets battery data and makes device appear like it is not
@@ -1542,7 +1545,7 @@ class DeviceUtils(object):
                          check_return=True)
     timeout_retry.WaitFor(battery_updates_disabled, wait_period=1)
 
-  # TODO(rnephew): Make private when all use cases can use the context manager.
+  # TODO(rnephew): Remove when battery_utils is switched to.
   @decorators.WithTimeoutAndRetriesFromInstance()
   def EnableBatteryUpdates(self, timeout=None, retries=None):
     """ Restarts device charging so that dumpsys no longer collects power data.
@@ -1559,6 +1562,7 @@ class DeviceUtils(object):
     self.RunShellCommand(['dumpsys', 'battery', 'reset'], check_return=True)
     timeout_retry.WaitFor(battery_updates_enabled, wait_period=1)
 
+  # TODO(rnephew): Remove when battery_utils is switched to.
   @contextlib.contextmanager
   def BatteryMeasurement(self, timeout=None, retries=None):
     """Context manager that enables battery data collection. It makes
@@ -1648,3 +1652,11 @@ class DeviceUtils(object):
       return parallelizer.Parallelizer(devices)
     else:
       return parallelizer.SyncParallelizer(devices)
+
+  def GetCacheEntry(self, key):

[jbudorick, 2015/03/27 13:26:36]

We talked about protecting cache users from overwriting each other's entries
(and from overwriting DeviceUtils's entries). This does not do that.

Perhaps that cache could be implemented in a separate class and DeviceUtils owns
an instance and manages its lifetime?

[rnephew (Wrong account), 2015/03/27 22:17:02]

I've made it so it wont override what others put in, unless explicitly told to.
I'll work on making it its own class as well.

+    """Cache getter."""
+    return self._cache.get(key)
+
+  def SetCacheEntry(self, key, value):
+    """Cache setter."""
+    self._cache[key] = value