Log source with visibility change

- Add a method in VisibilityLoggerMixin to log visible event using
  LogMaker, which allows logging additional FIELD_CONTEXT field.
- In Utils.startFragment, add current page's metricsCategory as an extra
  to next page.
- In next page's onResume(), extract the previous page's metricsCategory
  and send it to VisibilityLoggerMixin.visible()
- Update all caller with additional paramters

Change-Id: I8e1f2597fa465b7d3aa16fa1d21c052a3219694a
Fix: 35359289
Test: RunSettingsRoboTests

src/com/android/settings/datausage/DataUsagePreference.java

@@ -22,6 +22,8 @@ import android.support.v7.preference.Preference;
 import android.telephony.SubscriptionManager;
 import android.text.format.Formatter;
 import android.util.AttributeSet;
+
+import com.android.internal.logging.nano.MetricsProto;
 import com.android.settings.Utils;
 import com.android.settingslib.net.DataUsageController;
 import com.android.settings.R;
@@ -53,6 +55,7 @@ public class DataUsagePreference extends Preference implements TemplatePreferenc
         args.putParcelable(DataUsageList.EXTRA_NETWORK_TEMPLATE, mTemplate);
         args.putInt(DataUsageList.EXTRA_SUB_ID, mSubId);
         return Utils.onBuildStartFragmentIntent(getContext(), DataUsageList.class.getName(), args,
-                getContext().getPackageName(), 0, getTitle(), false);
+                getContext().getPackageName(), 0, getTitle(), false,
+                MetricsProto.MetricsEvent.VIEW_UNKNOWN);
     }
 }