Port ConsumerSharedCARingBuffer::Handle to the new IPC serialization format.
Pull request: https://github.com/WebKit/WebKit/pull/21401
Committed 271672@main (949236d50e89): <https://commits.webkit.org/271672@main> Reviewed commits have been landed. Closing PR #21401 and removing active labels.
<rdar://problem/119316489>