Chagaev vs Browne isn't for the heavyweight championship of the world. It's a B-title with little value.
Haye said that he is aiming to fight the winner. Then be the WBA-champ and unify it in Fury or Wilder fight.
Fury is the WBA-champ, there will be nothing to unify for Haye. You don't see Chagaev as the current WBA world champ, do you?