code: static DirectionsRoute extractRoute(Context context) {
      SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
      String directionsRouteJson = preferences.getString(NavigationConstants.NAVIGATION_VIEW_ROUTE_KEY, "");
      return DirectionsRoute.fromJson(directionsRouteJson);
    }
docs: Used to extract the route used to launch the drop-in UI.
  <p>
  Extracts the route {@link String} from {@link SharedPreferences} and converts
  it back to a {@link DirectionsRoute} object with {@link Gson}.
  
  @param context to retrieve {@link SharedPreferences}
  @return {@link DirectionsRoute} stored when launching