Update Summary for Battery Optimization

Bug: 37221696
Test: RunSettingsRoboTests
Change-Id: I7dc24879521a1375e0ad4b4b73e9a40633b93c3f

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

@@ -18,6 +18,8 @@ package com.android.settings.fuelgauge;
 import android.os.IDeviceIdleController;
 import android.os.RemoteException;
 import android.os.ServiceManager;
+import android.support.annotation.VisibleForTesting;
+
 import android.util.ArraySet;
 import android.util.Log;
 
@@ -31,7 +33,7 @@ public class PowerWhitelistBackend {
 
     private static final String DEVICE_IDLE_SERVICE = "deviceidle";
 
-    private static final PowerWhitelistBackend INSTANCE = new PowerWhitelistBackend();
+    private static PowerWhitelistBackend sInstance;
 
     private final IDeviceIdleController mDeviceIdleService;
     private final ArraySet<String> mWhitelistedApps = new ArraySet<>();
@@ -73,7 +75,8 @@ public class PowerWhitelistBackend {
         }
     }
 
-    private void refreshList() {
+    @VisibleForTesting
+    void refreshList() {
         mSysWhitelistedApps.clear();
         mWhitelistedApps.clear();
         try {
@@ -91,7 +94,10 @@ public class PowerWhitelistBackend {
     }
 
     public static PowerWhitelistBackend getInstance() {
-        return INSTANCE;
+        if (sInstance == null) {
+            sInstance = new PowerWhitelistBackend();
+        }
+        return sInstance;
     }
 
 }