Make BatterySettings Asynchronous and use enhanced estimate

this CL changes BatteryInfo methods to all use the async style
callback approach it had for one of the methods. Non-async methods
are now annotated to only be used in worker threads. BatteryInfo
can now be obtained via callback by calling one of the async
methods. Alternatively if there is a worker thread available
the synchronous methods similar to the old ones can be used.

The callback methods have all been changed so that they cascade to a
async method that takes all the required info as paremeters. This
will minimize the amount of churn in files that currently use
BatteryInfo.

A new loader was created that can be used to get BatteryInfo in
places that wish to get it. This loader is used in
PowerUsageSummary to get the BatteryInfo.

Test: Robotests
Bug: 38399275
Bug: 38398949
Bug: 38399654
Change-Id: Ic5a82d8ca4c85fad1b883226327ec083badf861d

src/com/android/settings/fuelgauge/BatteryHistoryPreference.java

@@ -17,7 +17,6 @@
 package com.android.settings.fuelgauge;
 
 import android.content.Context;
-import android.os.SystemClock;
 import android.support.annotation.VisibleForTesting;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceViewHolder;
@@ -43,10 +42,10 @@ public class BatteryHistoryPreference extends Preference {
     }
 
     public void setStats(BatteryStatsHelper batteryStats) {
-        final long elapsedRealtimeUs = SystemClock.elapsedRealtime() * 1000;
-        mBatteryInfo = BatteryInfo.getBatteryInfo(getContext(), batteryStats.getBatteryBroadcast(),
-                batteryStats.getStats(), elapsedRealtimeUs);
-        notifyChanged();
+        BatteryInfo.getBatteryInfo(getContext(), info -> {
+            mBatteryInfo = info;
+            notifyChanged();
+        }, batteryStats.getStats(), false);
     }
 
     @Override