[Robustness] protect get battery stats from DeadSystemException

Refine the original workaround patch in the ag/15527095 from NPE to
return default BatteryUsageStats instance as we merged in the
ag/15919139 (align the same solution).

Bug: 195306545
Test: make SettingsRoboTests
Change-Id: Ic03e8296d16ecb8629155f75727e9cde48c303eb

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

@@ -162,7 +162,9 @@ public class BatteryInfo {
                                 .getBatteryUsageStats();
                     } catch (RuntimeException e) {
                         Log.e(TAG, "getBatteryInfo() from getBatteryUsageStats()", e);
-                        return null;
+                        // Use default BatteryUsageStats.
+                        stats = new BatteryUsageStats.Builder(
+                                new String[0], /* includePowerModels */ false).build();
                     }
                 }
                 return getBatteryInfo(context, stats, shortString);

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

@@ -48,7 +48,9 @@ public class BatteryUsageStatsLoader extends AsyncLoaderCompat<BatteryUsageStats
             return mBatteryStatsManager.getBatteryUsageStats(builder.build());
         } catch (RuntimeException e) {
             Log.e(TAG, "loadInBackground() for getBatteryUsageStats()", e);
-            return null;
+            // Use default BatteryUsageStats.
+            return new BatteryUsageStats.Builder(
+                    new String[0], /* includePowerModels */ false).build();
         }
     }
 

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

@@ -373,8 +373,11 @@ public class BatteryUtils {
             batteryUsageStats = systemService.getBatteryUsageStats(
                     new BatteryUsageStatsQuery.Builder().includeBatteryHistory().build());
         } catch (RuntimeException e) {
-            Log.e(TAG, "getBatteryInfo() from getBatteryUsageStats()", e);
+            Log.e(TAG, "getBatteryInfo() error from getBatteryUsageStats()", e);
-            return null;
+            // Use default BatteryUsageStats.
+            batteryUsageStats =
+                    new BatteryUsageStats.Builder(new String[0], /* includePowerModels */ false)
+                            .build();
         }
 
         final long startTime = System.currentTimeMillis();

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

@@ -25,7 +25,6 @@ import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
 import android.provider.Settings.Global;
-import android.util.Log;
 
 import androidx.annotation.VisibleForTesting;
 import androidx.loader.app.LoaderManager;
@@ -104,10 +103,6 @@ public class PowerUsageSummary extends PowerUsageBase implements
 
                 @Override
                 public void onLoadFinished(Loader<BatteryInfo> loader, BatteryInfo batteryInfo) {
-                    if (batteryInfo == null) {
-                        Log.w(TAG, "mBatteryInfoLoaderCallbacks: batteryInfo = null");
-                        return;
-                    }
                     mBatteryHeaderPreferenceController.updateHeaderPreference(batteryInfo);
                     mBatteryHeaderPreferenceController.updateHeaderByBatteryTips(
                             mBatteryTipPreferenceController.getCurrentBatteryTip(), batteryInfo);
@@ -131,10 +126,6 @@ public class PowerUsageSummary extends PowerUsageBase implements
                 @Override
                 public void onLoadFinished(Loader<List<BatteryTip>> loader,
                         List<BatteryTip> data) {
-                    if (mBatteryInfo == null) {
-                        Log.w(TAG, "mBatteryTipsCallbacks: batteryInfo = null");
-                        return;
-                    }
                     mBatteryTipPreferenceController.updateBatteryTips(data);
                     mBatteryHeaderPreferenceController.updateHeaderByBatteryTips(
                             mBatteryTipPreferenceController.getCurrentBatteryTip(), mBatteryInfo);

src/com/android/settings/fuelgauge/batterytip/BatteryTipLoader.java

@@ -18,7 +18,6 @@ package com.android.settings.fuelgauge.batterytip;
 
 import android.content.Context;
 import android.os.BatteryUsageStats;
-import android.util.Log;
 
 import androidx.annotation.VisibleForTesting;
 
@@ -68,16 +67,11 @@ public class BatteryTipLoader extends AsyncLoaderCompat<List<BatteryTip>> {
         final BatteryInfo batteryInfo = mBatteryUtils.getBatteryInfo(TAG);
         final Context context = getContext();
 
-        tips.add(new EarlyWarningDetector(policy, context).detect());
-        if (batteryInfo == null) {
-            Log.w(TAG, "loadInBackground() batteryInfo = null");
-            return tips;
-        }
-
         tips.add(new LowBatteryDetector(context, policy, batteryInfo).detect());
         tips.add(new HighUsageDetector(context, policy, mBatteryUsageStats, batteryInfo).detect());
         tips.add(new SmartBatteryDetector(
                 context, policy, batteryInfo, context.getContentResolver()).detect());
+        tips.add(new EarlyWarningDetector(policy, context).detect());
         tips.add(new BatteryDefenderDetector(batteryInfo).detect());
         Collections.sort(tips);
         return tips;