Refactor background optimization mode in Power Usage Detail page.

[Screenshot]:
before: https://screenshot.googleplex.com/6m5jYWHofY2pFov

after:
[App battery usage]
- [normal] https://screenshot.googleplex.com/7aurWk7cHKaWds7
- [always unrestried/optimized] https://screenshot.googleplex.com/3rGAh4ccUYTKBAr

[Allow Background usage]
- [Restricted]: https://screenshot.googleplex.com/MPXjQe5kPWw2nhr
- [Optimized]: https://screenshot.googleplex.com/6w4zTT6r34APnGc
- [Unrestricted]: https://screenshot.googleplex.com/97FgvHWMrwASqYH

Bug: 302063050
Bug: 306295660
Bug: 308359833
Test: manual
Change-Id: I3237d015549fe26e62d6d68c13403cc2cbdf0017

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

@@ -17,7 +17,6 @@
 package com.android.settings.fuelgauge;
 
 import android.content.Context;
-import android.util.Log;
 
 import androidx.annotation.VisibleForTesting;
 import androidx.preference.Preference;
@@ -31,7 +30,9 @@ public class UnrestrictedPreferenceController extends AbstractPreferenceControll
 
     private static final String TAG = "UNRESTRICTED_PREF";
 
-    @VisibleForTesting String KEY_UNRESTRICTED_PREF = "unrestricted_pref";
+    @VisibleForTesting
+    static final String KEY_UNRESTRICTED_PREF = "unrestricted_preference";
+
     @VisibleForTesting BatteryOptimizeUtils mBatteryOptimizeUtils;
 
     public UnrestrictedPreferenceController(Context context, int uid, String packageName) {
@@ -41,26 +42,11 @@ public class UnrestrictedPreferenceController extends AbstractPreferenceControll
 
     @Override
     public void updateState(Preference preference) {
+        preference.setEnabled(mBatteryOptimizeUtils.isSelectorPreferenceEnabled());
 
-        if (mBatteryOptimizeUtils.isDisabledForOptimizeModeOnly()) {
-            Log.d(TAG, "disable preference for " + mBatteryOptimizeUtils.getPackageName());
-            preference.setEnabled(false);
-            return;
-        } else {
-            preference.setEnabled(true);
-        }
-
-        if (mBatteryOptimizeUtils.getAppOptimizationMode()
-                == BatteryOptimizeUtils.MODE_UNRESTRICTED) {
-            Log.d(TAG, "is unrestricted states");
-            ((SelectorWithWidgetPreference) preference).setChecked(true);
-        } else {
-            ((SelectorWithWidgetPreference) preference).setChecked(false);
-            if (mBatteryOptimizeUtils.isSystemOrDefaultApp()) {
-                Log.d(TAG, "is system or default app, disable pref");
-                preference.setEnabled(false);
-            }
-        }
+        final boolean isUnrestricted = mBatteryOptimizeUtils.getAppOptimizationMode()
+                == BatteryOptimizeUtils.MODE_UNRESTRICTED;
+        ((SelectorWithWidgetPreference) preference).setChecked(isUnrestricted);
     }
 
     @Override