Add display settings dashboard to new IA.

- Added a activity-alias pointing to displaySettings as top level
  setting item.
- Refactored all preference logic in DisplaySettings into
  PreferenceControllers. During fragment onAttach it installs all
  controllers, and during onResume it updates preference state. Each
  controller listens to its own preference change event.

Bug: 31800242
Test: RunSettingsRoboTests
Change-Id: Ibc9bf200c5acce7c4ae9292340822afee27a3a28

src/com/android/settings/deviceinfo/StorageDashboardFragment.java

@@ -20,6 +20,7 @@ import android.content.Context;
 import android.provider.SearchIndexableResource;
 
 import com.android.settings.R;
+import com.android.settings.core.PreferenceController;
 import com.android.settings.dashboard.DashboardFragment;
 import com.android.settings.overlay.FeatureFactory;
 import com.android.settings.search.BaseSearchIndexProvider;
@@ -44,23 +45,21 @@ public class StorageDashboardFragment extends DashboardFragment {
         return TAG;
     }
 
-    @Override
-    public void onAttach(Context context) {
-        super.onAttach(context);
-        addPreferenceController(new ManageStoragePreferenceController(context));
-    }
-
     @Override
     protected String getCategoryKey() {
         return CategoryKey.CATEGORY_STORAGE;
     }
 
     @Override
-    protected void displayResourceTiles() {
-        addPreferencesFromResource(R.xml.storage_dashboard_fragment);
+    protected int getPreferenceScreenResId() {
+        return R.xml.storage_dashboard_fragment;
+    }
 
-        getPreferenceController(ManageStoragePreferenceController.class)
-                .displayPreference(getPreferenceScreen());
+    @Override
+    protected List<PreferenceController> getPreferenceControllers(Context context) {
+        final List<PreferenceController> controllers = new ArrayList<>();
+        controllers.add(new ManageStoragePreferenceController(context));
+        return controllers;
     }
 
     /**