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/applications/ConvertToFbe.java

@@ -79,7 +79,7 @@ public class ConvertToFbe extends SettingsPreferenceFragment {
 
     private void convert() {
         SettingsActivity sa = (SettingsActivity) getActivity();
-        sa.startPreferencePanel(ConfirmConvertToFbe.class.getName(), null,
+        sa.startPreferencePanel(this, ConfirmConvertToFbe.class.getName(), null,
                                 R.string.convert_to_file_encryption, null, null, 0);
     }