Changes

[https://mozillagfx.wordpress.com/2017/12/05/off-main-thread-painting/ Off Main Thread Painting]: With OMTP the visual state of the page is still computed on the main thread, but the potentially costly task of rasterization is passed off to a designated “rasterization thread”, and the main thread can carry on and stay responsive. (Firefox 58 on Windows, 59 on Mac)

[https://bugzilla.mozilla.org/show_bug.cgi?id=1385403 OOP Extensions for Mac] and [https://bugzilla.mozilla.org/show_bug.cgi?id=1357487 Linux]: We've already shipped out of process extensions for Windows leading to faster page loads and more browser responsiveness. This year we'll catch up on Mac and Linux. (Mac 61, Linux 2018)