Planning: remove default speed and always search

modules/planning/tasks/optimizers/path_time_heuristic/gridded_path_time_graph.cc

@@ -97,23 +97,6 @@ Status GriddedPathTimeGraph::Search(SpeedData* const speed_data) {
     }
   }
 
-  // TODO(Hongyi): remove default speed and always search
-  // if (st_graph_data_.st_boundaries().empty()) {
-  //   ADEBUG << "No path obstacles, dp_st_graph output default speed profile.";
-  //   std::vector<SpeedPoint> speed_profile;
-  //   const double v_default = FLAGS_default_cruise_speed;
-  //   for (int i = 0; i <= dp_st_speed_config_.matrix_dimension_t(); ++i) {
-  //     SpeedPoint speed_point;
-  //     speed_point.set_s(i * unit_t_ * v_default);
-  //     speed_point.set_t(i * unit_t_);
-  //     speed_point.set_v(v_default);
-  //     speed_point.set_a(0.0);
-  //     speed_profile.emplace_back(std::move(speed_point));
-  //   }
-  //   *speed_data = SpeedData(std::move(speed_profile));
-  //   return Status::OK();
-  // }
-
   if (!InitCostTable().ok()) {
     const std::string msg = "Initialize cost table failed.";
     AERROR << msg;