Bug 1766498 - Disable raster root adjustment for backdrop-filters r=gfx-reviewers,lsalzman
Bug 1766498 - Disable raster root adjustment for backdrop-filters r=gfx-reviewers,lsalzman

This breaks an assumption that the surface spatial node for the
resolve surface matches that of the backdrop root. In future we
might be able to support snapping in this use case, but I'm not
convinced it's actually useful to have that anyway yet.

Differential Revision: https://phabricator.services.mozilla.com/D145504

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/899daaf2bc1661e07397083e293a290af5301364

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