Not sure if that's true, since Chrome usually performs quite well with HTML5 stuff. As I mentioned in my earlier post it did beat Ffox in a little test I made
Did you test Firefox 5? FF5 added decent hardware acceleration, FF4 didn't have that.
lso when you go to the address about:flags in Chrome you can see an option 'GPU Accelerated Canvas 2D' which should be activated by default.
It's disabled by default in Chrome 12 - at least on my machine. If you enable it you should get decent performance, but judging by the framerates it's not enabled by default. I'm hoping they do turn it on in a future build soon though!
It's also possible browsers have incomplete acceleration - i.e. it uses hardware acceleration, unless you use some particular feature (e.g. the lighting in the demo), in which case it falls back to slow software mode.
Chrome does have one of the best software renderers though - in software mode it's far faster than Firefox in software mode, which would explain your result. Assuming only FF5 and IE9 have default-enabled hardware acceleration, they should both beat Chrome right now.