The various CDM related classes are using FragmentedSharedBuffer when all buffers received/sent are contiguous. It also makes use of SharedBufferCopy to send things over IPC which isn't necessary when using SharedBuffer.
<rdar://problem/92780561>
Pull request: https://github.com/WebKit/WebKit/pull/525
Committed r293881 (250339@main): <https://commits.webkit.org/250339@main> Reviewed commits have been landed. Closing PR #525 and removing active labels.