That call on the possible helmet-to-helmet goes both ways but mostly goes uncalled. The defender typically gets benefit of the doubt when he's got his eyes on the QB's chest and leads with his facemask vs. his actual helmet. It wasn't really helmet to helmet so much as it was facemask to facemask. I'm okay with the non call there.
It's definitely a judgment call and in this case I was fine with the flag not being thrown since it wasn't a lopsided officiating performance with the same call going against the niners.
I also would have been fine with the flag being thrown since he did hit him in the chinstrap and they say "head and neck area."