Add quickUpdate method to BatteryHeaderPrefCtrl

This cl adds a method called quickUpdateHeaderPreference, which will
update the following items immediately without waiting for the
BatteryInfo:
1. Battery level
2. Battery charging status(whether to show lighting bolt)
3. Clear the charging summary

Note: this cl doesn't optimize the BatteryInfo loading time.

This cl also rename "TimeText" to "BatteryPercentText" because in
new UI that textview is used to display battery percentage.

Bug: 63029231
Test: RunSettingsRoboTests
Change-Id: I8cc886b35e937d73b46e47e303ff0994ccdcb61c

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

@@ -856,6 +856,12 @@ public class PowerUsageSummary extends PowerUsageBase implements
         performBatteryHeaderClick();
     }
 
+    @Override
+    protected void restartBatteryStatsLoader() {
+        super.restartBatteryStatsLoader();
+        mBatteryHeaderPreferenceController.quickUpdateHeaderPreference();
+    }
+
     private static class SummaryProvider implements SummaryLoader.SummaryProvider {
         private final Context mContext;
         private final SummaryLoader mLoader;