message: only adding point if there is a lane (and a polygon)
diff: @@ -642,11 +642,9 @@ std::pair<PolygonPtr, bool> Roadgraph::ComputeLanePolygon(const LaneId &lane_id)
  {
  polygon->add_point(p);
  }
  - }
  // Polygons need to be closed!
  polygon->add_point(*(lb.first->get_line().begin()));
  - // Does not work with Point2d
  - // geometry::bg::correct(*polygon);
  + }
  return std::make_pair(polygon, success);
  }
  PolygonPtr Roadgraph::get_lane_polygon_by_id(const LaneId &lane_id) {
  