This is a split from the original bug 240223 patch. Aim is to provide a smoother transition. SharedBufferCopy will be renamed into SharedBufferReference and be reworked so that the underlying SharedMemory can be easily access, which is required when attempting to assign ownership.
<rdar://problem/93754681>
Pull request: https://github.com/WebKit/WebKit/pull/968
Committed r294790 (250949@main): <https://commits.webkit.org/250949@main> Reviewed commits have been landed. Closing PR #968 and removing active labels.