Dragon counter alows teams to keep track of dragon timer without seeing it die.
Basically the new dragon counter, the one that alows you to see how many dragons each team has, updates for both teams even if one team does not have vision of drag. Meaning that the timer on drag is given anyways. Not only does this give the other team a timer it allows them to know where the jungler is, if their trying to sneak it, without any vision.