Directly use BaseIndexableProvider

- Add function getXmlResourceId, Fragments don't need to write
xml resource id twice.
- Remove getPreferenceControllers from Indexable.java. Because it will
move to SettingsLib later for other apps which don't need this function

Bug: 135053028
Test: robolectric
Change-Id: I1e74519aecdea3dde64a5aea79f08d766dbc0003

tests/robotests/src/com/android/settings/dashboard/DashboardFragmentSearchIndexProviderInspector.java

@@ -22,6 +22,7 @@ import androidx.fragment.app.Fragment;
 
 import com.android.settings.core.BasePreferenceController;
 import com.android.settings.core.PreferenceControllerListHelper;
+import com.android.settings.search.BaseSearchIndexProvider;
 import com.android.settings.search.DatabaseIndexingUtils;
 import com.android.settings.search.Indexable;
 import com.android.settingslib.core.AbstractPreferenceController;
@@ -45,8 +46,8 @@ public class DashboardFragmentSearchIndexProviderInspector {
             return true;
         }
 
-        final Indexable.SearchIndexProvider provider =
-                DatabaseIndexingUtils.getSearchIndexProvider(clazz);
+        final BaseSearchIndexProvider provider =
+                (BaseSearchIndexProvider) DatabaseIndexingUtils.getSearchIndexProvider(clazz);
         if (provider == null) {
             return true;
         }