Planning: modified point(index) function in st_graph_boundary, return STPoint for easier usage.

modules/planning/optimizer/st_graph/st_graph_boundary.cc

@@ -79,9 +79,9 @@ bool StGraphBoundary::IsPointInBoundary(const STPoint& st_point) const {
   return IsPointIn(st_point);
 }
 
-Vec2d StGraphBoundary::point(const uint32_t index) const {
+STPoint StGraphBoundary::point(const uint32_t index) const {
   CHECK_LT(index, points_.size()) << "Index[" << index << "] is out of range.";
-  return points_[index];
+  return STPoint(points_[index].y(), points_[index].x());
 }
 
 const std::vector<Vec2d>& StGraphBoundary::points() const { return points_; }

modules/planning/optimizer/st_graph/st_graph_boundary.h

@@ -60,7 +60,7 @@ class StGraphBoundary : public common::math::Polygon2d {
   bool IsPointInBoundary(const StGraphPoint& st_graph_point) const;
   bool IsPointInBoundary(const STPoint& st_point) const;
 
-  common::math::Vec2d point(const uint32_t index) const;
+  STPoint point(const uint32_t index) const;
   const std::vector<common::math::Vec2d>& points() const;
 
   BoundaryType boundary_type() const;