Simplify several IPC sending call sites in the UIProcess by leveraging the fact that WebPageProxy subclasses IPC::MessageSender.
Created attachment 398739 [details] Patch
Committed r261299: <https://trac.webkit.org/changeset/261299> All reviewed patches have been landed. Closing bug and clearing flags on attachment 398739 [details].
<rdar://problem/62980581>