<rdar://33925578> https://bugs.webkit.org/show_bug.cgi?id=206514 fixed this for GTK. We won't be able to do element snapshots this way yet though since we can't get snapshots in the UIProcess of stuff that isn't part of the viewport.
Pull request: https://github.com/WebKit/WebKit/pull/1968
<rdar://33925578>
Committed 252201@main (dc2acd22d6be): <https://commits.webkit.org/252201@main> Reviewed commits have been landed. Closing PR #1968 and removing active labels.