Remove WebPasteBoardProxy::PasteboardCopy as it is dead code.
<rdar://problem/59658727>
Created attachment 391400 [details] Patch
Comment on attachment 391400 [details] Patch r=me
Comment on attachment 391400 [details] Patch Clearing flags on attachment: 391400 Committed r257145: <https://trac.webkit.org/changeset/257145>
All reviewed patches have been landed. Closing bug.