Apple webkit is already in the backend starting to be rebuilt for mobile with native mobile hook's. The webkit on iOS is actually a spinoff thats maintained separately, there is a lot of work to do but thats why web wrapper apps work so well on iOS for performance is a lot of the native webkit is talking direct to hardware. For Android they are doing the same thing, but it's not been optimized for mobile first hardware, but then again it's so hard with android to do that.