Reduce the number of copies made during SourceBufferPrivateAVFObjC::append() using SharedBuffer
<rdar://problem/49175604>
<rdar://problem/50263451>
Created attachment 368372 [details] Patch
Comment on attachment 368372 [details] Patch Will cq+ once the EWS bots chew through this patch.
Comment on attachment 368372 [details] Patch Clearing flags on attachment: 368372 Committed r244716: <https://trac.webkit.org/changeset/244716>
All reviewed patches have been landed. Closing bug.