> I'm sure Google would love to be able top bypass DNS based adblocking.

Google already does this with their Chromecast line of products.

Chromecasts will not adhere to your network's DNS servers, and will use Google's DNS servers. Chromecasts will fail to work at all if they cannot communicate with Google's DNS servers. If you try to redirect DNS traffic to the DNS servers of your choice, Chromecasts will not function. They won't work if you block Google's DNS servers, and you cannot change the DNS settings on the device itself.