Add a config to force rounded icon for DashboardFragment.

And each page has ability to turn on/off rounded icons. This CL only
adds the flag, it doesn't actually change icon shape yet.

- Boolean config in xml
- New protected method for each DashboardFragment to load config
- Plumb the boolean into DashboardFeatureProvider for future use.
- Remove some unused APIs from DashboardFeatureProvider

Bug: 110405144
Fixes: 79748104
Test: robotests
Change-Id: Id34782e75aa7289967e4dd1f4fe2978688092702

src/com/android/settings/homepage/TopLevelSettings.java

@@ -91,6 +91,12 @@ public class TopLevelSettings extends DashboardFragment implements
         return true;
     }
 
+    @Override
+    protected boolean shouldForceRoundedIcon() {
+        return getContext().getResources()
+                .getBoolean(R.bool.config_force_rounded_icon_TopLevelSettings);
+    }
+
     public static final SearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
             new BaseSearchIndexProvider() {
                 @Override