• Bug 1624627 - Add a slow transaction indicator. r=jrmuizel 

    It moves when DL building + IPC + scene building takes more than 100ms.

Depends on D69247

Differential Revision: https://phabricator.services.mozilla.com/D69254

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/af4366c6c434242d656db2c4b6779dd50a35b94a
    @nical @moz-gfx
    nical authored and moz-gfx committed Apr 3, 2020
    afa7706