Dragon a Haoshoku Haki user

Well today I want to talk about Dragon's powers. Well it's a fact that he can control the wind, but it's not confirmed if he is a devil fruit user. It's been almost 600 chapters since he displayed the ability and yet we don't know for sure. That's why I think that it's not a devil fruit but an advanced form of Haoshoku Haki. He is the most wanted man in the world he must posses Haoshoku Haki. Also when Luffy used haki at Marinford somebody (I don't remember who did right now) commented that "he did inherit it after all" so either he or Garp or both possess this ability.