Update BatteryUtils to update system battery estimate cache

To try and ensure SysUI and Settings don't show different battery
estimates we have settings always push the estimate to the system
cache which will cause the status bar to update as well.

Test: manually trigger battery broadcasts and observe
Bug: 124030091
Change-Id: I07a17ecf2a42c3022673ad2aca438f8d6e81b41f

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

@@ -20,9 +20,14 @@ import static com.android.settings.fuelgauge.BatteryBroadcastReceiver.BatteryUpd
 
 import android.app.settings.SettingsEnums;
 import android.content.Context;
+import android.database.ContentObserver;
+import android.net.Uri;
 import android.os.BatteryStats;
 import android.os.Bundle;
+import android.os.Handler;
 import android.provider.SearchIndexableResource;
+import android.provider.Settings;
+import android.provider.Settings.Global;
 import android.text.format.Formatter;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -102,6 +107,13 @@ public class PowerUsageSummary extends PowerUsageBase implements OnLongClickList
     BatteryTipPreferenceController mBatteryTipPreferenceController;
     private int mStatsType = BatteryStats.STATS_SINCE_CHARGED;
 
+    private final ContentObserver mSettingsObserver = new ContentObserver(new Handler()) {
+        @Override
+        public void onChange(boolean selfChange, Uri uri) {
+            restartBatteryInfoLoader();
+        }
+    };
+
     @VisibleForTesting
     LoaderManager.LoaderCallbacks<BatteryInfo> mBatteryInfoLoaderCallbacks =
             new LoaderManager.LoaderCallbacks<BatteryInfo>() {
@@ -189,6 +201,21 @@ public class PowerUsageSummary extends PowerUsageBase implements OnLongClickList
                 }
             };
 
+    @Override
+    public void onStop() {
+        getContentResolver().unregisterContentObserver(mSettingsObserver);
+        super.onStop();
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        getContentResolver().registerContentObserver(
+                Global.getUriFor(Global.BATTERY_ESTIMATES_LAST_UPDATE_TIME),
+                false,
+                mSettingsObserver);
+    }
+
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);