explicit GenericGraph(Zone* zone)
: GenericGraphBase(zone), start_(NULL), end_(NULL) {}
- V* start() { return start_; }
- V* end() { return end_; }
+ V* start() const { return start_; }
+ V* end() const { return end_; }
void SetStart(V* start) { start_ = start; }
void SetEnd(V* end) { end_ = end; }