Schaub via decision or late sub.
He'd outstrike Roy and wear him down, possibly getting a sub when a BADLY gassed Roy is looking for a desperation TD. Although I wouldn't be surprised to see Schaub finish Roy late with strikes.
People don't like him, but Schaub is a threat to anyone in the division on the feet or on the ground, and all Roy has is an ability to get punched in the face, and an overhand right that serves to gas him out if it doesn't land AND lead to a finish.
Schaub will be challenging Cain or JDS for the title one day soon, mark my words. MARK THEM.