We need to add several IPC messages to RemoteMediaSourceProxy and MediaSourcePrivateRemote to support seeking.
Created attachment 415830 [details] Patch
<rdar://problem/72166804>
Created attachment 415832 [details] Patch
Committed r270639: <https://trac.webkit.org/changeset/270639> All reviewed patches have been landed. Closing bug and clearing flags on attachment 415832 [details].