A point no one has brought up is that Mozilla is spending huge amounts of
effort to improve their browser, the entirety of which we can take
advantage of vs the situation with WebKit and how it is not used by any
major browser in its entirety (yes, the js engine matters, a lot).
Related to the first point is Mozilla's work on azure. Currently in nightly
you can switch drawing libraries from Cairo to skia. Yes, it's too unstable
to use by default, for now, but it provides nice speedups for canvas
operations, and uses less power (I.e., my fan didn't need to crank on).
When we make the move to Wayland we're going to be relying on glamour to
provide our 2d acceleration and skia has a far better story when it comes
to gl acceleration.
Yeah, we're still stuck with Cairo, but there's no reason not to make the
situation better where we can.