Use SettingsLib Indexable

- Use SettingsLib Indexable
- Directly use resource id in getPreferenceScreenResId

Bug: 135053028
Test: roboletric
Change-Id: I05f493b55e8b6e2091301e9231ba5615215618e6
diff --git a/src/com/android/settings/LegalSettings.java b/src/com/android/settings/LegalSettings.java
index f6e13ea..9cb3bf4 100644
--- a/src/com/android/settings/LegalSettings.java
+++ b/src/com/android/settings/LegalSettings.java
@@ -39,7 +39,7 @@
 
     @Override
     protected int getPreferenceScreenResId() {
-        return SEARCH_INDEX_DATA_PROVIDER.getXmlResourceId();
+        return R.xml.about_legal;
     }
 
     public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =