Transitions and animations all require layers so they should live in RenderLayerModelObject
Created attachment 365044 [details] Patch
^^is not quite right. Move them all the way to RenderElement
Created attachment 365053 [details] Patch
Comment on attachment 365053 [details] Patch Clearing flags on attachment: 365053 Committed r243103: <https://trac.webkit.org/changeset/243103>
All reviewed patches have been landed. Closing bug.
<rdar://problem/48993955>