First off, Cruz is my favorite fighter so I might be biased.
Barao is a killer when people try to come down the middle on him. He kills people with the long jab and straight when they move in on him. Also, if you stay at a range, he destroys the legs with kicks. He is also a BEAST on the ground.
Cruz never comes down the middle to attack. It is always at an angle. Also, he never stays within anybodies range. The only problem is when he moves, he gets very heavy on his lead leg. He has good takedowns and is a great scambler. He is not the best BJJ player. He is also great any defending the takedown.
It would be a very interesting fight. If Barao cannot time Cruz with leg kicks, he gets picked apart on the feet. If Barao can take Cruz down, it would be interesting to see if he could keep him down. If he can, Cruz gets submitted.
I would pick Cruz to win a UD with solid TDD and confusing Barao with his angles. Barao would adjust in later rounds and start catching Cruz more but it would be too little too late.