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

src/com/android/settings/gestures/DoubleTapScreenSettings.java

@@ -72,6 +72,6 @@ public class DoubleTapScreenSettings extends DashboardFragment {
         return R.string.help_url_double_tap_screen;
     }
 
-    public static final SearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
+    public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
             new BaseSearchIndexProvider(R.xml.double_tap_screen_settings);
 }