We already have support for detached <img> and <picture> (r247814), as well as the various canvas rendering contexts, but not <canvas> itself.
Created attachment 376277 [details] Patch
Comment on attachment 376277 [details] Patch r=me
Comment on attachment 376277 [details] Patch Clearing flags on attachment: 376277 Committed r248736: <https://trac.webkit.org/changeset/248736>
All reviewed patches have been landed. Closing bug.
<rdar://problem/54357533>