Here is a serious question, in that 23 mins of Sonnen dominance was Silva ever in trouble?
Yes. He was less than 2 minutes away from losing the fight. I would call that trouble.
Also, using your head as punching bag on the ground isn't the best game plan. Regardless of your chin. You can't just sit there and hope that the next shot or shots aren't going to put you out. He was in trouble through the whole fight.