Add system app check for anomaly detection.

In this CL, don't blame system app in anomaly detection and also
add log for it.

Following CL will update it to also check whether this system app
has launch entry.

Bug: 77477987
Test: RunSettingsRoboTests
Change-Id: I97490b32bc42ec2f8e03ec2d82f7c8bf89f9c66f

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

@@ -25,7 +25,9 @@ import android.os.BatteryManager;
 import android.os.BatteryStats;
 import android.os.Bundle;
 import android.os.Build;
+import android.os.Process;
 import android.os.SystemClock;
+import android.os.UserHandle;
 import android.os.UserManager;
 import android.support.annotation.IntDef;
 import android.support.annotation.Nullable;
@@ -43,6 +45,7 @@ import com.android.settings.R;
 import com.android.settings.fuelgauge.anomaly.Anomaly;
 import com.android.settings.overlay.FeatureFactory;
 
+import com.android.settingslib.fuelgauge.PowerWhitelistBackend;
 import com.android.settingslib.utils.PowerUtil;
 
 import java.lang.annotation.Retention;
@@ -531,5 +534,40 @@ public class BatteryUtils {
 
         return false;
     }
+
+    /**
+     * Return {@code true} if we should hide anomaly app represented by {@code uid}
+     */
+    public boolean shouldHideAnomaly(PowerWhitelistBackend powerWhitelistBackend, int uid) {
+        final String[] packageNames = mPackageManager.getPackagesForUid(uid);
+        if (ArrayUtils.isEmpty(packageNames)) {
+            // Don't show it if app has been uninstalled
+            return true;
+        }
+
+        return isSystemUid(uid) || isSystemApp(mPackageManager, packageNames)
+                || powerWhitelistBackend.isSysWhitelistedExceptIdle(packageNames);
+    }
+
+    private boolean isSystemUid(int uid) {
+        final int appUid = UserHandle.getAppId(uid);
+        return appUid >= Process.ROOT_UID && appUid < Process.FIRST_APPLICATION_UID;
+    }
+
+    private boolean isSystemApp(PackageManager packageManager, String[] packageNames) {
+        for (String packageName : packageNames) {
+            try {
+                final ApplicationInfo info = packageManager.getApplicationInfo(packageName,
+                        0 /* flags */);
+                if ((info.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
+                    return true;
+                }
+            } catch (PackageManager.NameNotFoundException e) {
+                Log.e(TAG, "Package not found: " + packageName, e);
+            }
+        }
+
+        return false;
+    }
 }