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

tests/robotests/src/com/android/settings/core/BasePreferenceControllerTest.java

@@ -28,6 +28,7 @@ import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
+import android.app.settings.SettingsEnums;
 import android.content.Context;
 
 import androidx.preference.Preference;
@@ -205,6 +206,15 @@ public class BasePreferenceControllerTest {
         assertThat(keys).isEmpty();
     }
 
+    @Test
+    public void getMetricsCategory_metricsCategoryIsSet_shouldReturnTheSameCategory() {
+        mPreferenceController.setMetricsCategory(SettingsEnums.DISPLAY);
+
+        final int category = mPreferenceController.getMetricsCategory();
+
+        assertThat(category).isEqualTo(SettingsEnums.DISPLAY);
+    }
+
     private class FakeBasePreferenceController extends BasePreferenceController {
 
         private int mAvailable;