Not sure why I got a down vote for this. Probably as it's anecdotal? What I should have said: from my experience Chrome feels snappier with Javascript performance at least while playing typeracer. And I read into that, that JS games perform better under Chrome.
I wouldn't worry about random downvotes, no karma system works. 'snappiness' is a potential driving factor for Chrome use. I'll try and do some research on users at some point.
Chrome - 63.1%
Firefox - 21.1%
IE - 7.1%
These are heavily biased towards young (13-25) Windows users who play games.
I've noticed the massive dominance of Chrome for some time, but the numbers are not clear enough to show a rise or fall in its use over time.