Code similar to the implementation of OffscreenCanvas::transferToImageBitmap() would probably work for the default case, but not if there's any resizing involved.
Created attachment 380626 [details]
Created attachment 384306 [details]
Comment on attachment 384306 [details]
Clearing flags on attachment: 384306
Committed r253031: <https://trac.webkit.org/changeset/253031>
All reviewed patches have been landed. Closing bug.