Source: https://hacks.mozilla.org/2016/01/webgl-off-the-main-thread/
HN comments: https://news.ycombinator.com/item?id=10954552
As the source post says, rAF in workers is coming.
Also, from the other day: https://twitter.com/LostOracle/status/687754936910675968
Wooohoooo! The web will win! 
Eventually, yeah. In the interim it’s going to be tricky navigating the waters ahead.
It’s probably going to take at least a year and a half for WebGL in workers, rAF in workers, SharedArrayBuffer, WebAssembly, WebGL2—let alone basic worker behavior that conforms to spec—to be supported across multiple browsers.
Web Assembly kind of complicates the whole picture. Soon it might make more sense to write something like Infamous in C, or at least the performance-critical parts of it.
I foresee lots of feature testing and fallback support ahead. 
True. As such, I’ve shifted focus from workers to the API (for now), and will be adding an HTML layer next (ala A-Frame). I want to get the top-level html and imperative APIs to be nice and simple, then when the time comes the implementation below can morph, with the goal of changing the top level as little as possible (or, as incrementally as possible).