We currently have a backing store ID that we change every time the drawing area is resized or new backing store is created and sent to the web process waiting for a response. It can be simplified by using that only for size changes and use an message with async reply to handle the response.
Pull request: https://github.com/WebKit/WebKit/pull/12697
Committed 263118@main (ff2d14cf13d0): <https://commits.webkit.org/263118@main> Reviewed commits have been landed. Closing PR #12697 and removing active labels.
<rdar://problem/108246986>