Bug 1663732 - Hook up GeckoView's CompositorController.setClearColor() to webrender. r=nical
Bug 1663732 - Hook up GeckoView's CompositorController.setClearColor() to webrender. r=nical

Differential Revision: https://phabricator.services.mozilla.com/D90098

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/c4b987da7cfc20a20d8139487a1021e4e889f9c7

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender