Refine metrics log in infrastructure

- Add interfaces to set/get metrics category in BasePreferenceController
  for descendants having a chance to get it.
- Set metrics category in DashboardFragment
- Automatically log metrics in onPreferenceChange of
  TogglePreferenceController
- Add support for TwoStateButtonPreference in TogglePreferenceController
  to make the preference generic

Bug: 137559984
Test: robotest
Change-Id: Ia7e0d24a3db1991b18e0286d9894570fa71247a3

src/com/android/settings/dashboard/DashboardFragment.java

@@ -113,6 +113,14 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
             }
         });
 
+        // Set metrics category for BasePreferenceController.
+        final int metricCategory = getMetricsCategory();
+        mControllers.forEach(controller -> {
+            if (controller instanceof BasePreferenceController) {
+                ((BasePreferenceController) controller).setMetricsCategory(metricCategory);
+            }
+        });
+
         mPlaceholderPreferenceController =
                 new DashboardTilePlaceholderPreferenceController(context);
         mControllers.add(mPlaceholderPreferenceController);