If it were 5 rounds Condit would figure out a way to put him down. His cardio is way better, his striking is a billion times better, and Shields' takedowns are pretty weak, generally, so I don't think he'd be able to get Condit down with any kind of regularity. Condit's very active off of his back too, so Shields would be taking a decent amount of damage and working extra hard to try to keep Condit down and advance position.
Unless Condit already fought 3 fights earlier in the night I think he'd TKO Shields late (round 4ish).