On iOS, add telemetry for message filtering in the WebContent process' sandbox.
<rdar://problem/60376722>
Created attachment 393997 [details] Patch
Comment on attachment 393997 [details] Patch Looks great!
Comment on attachment 393997 [details] Patch Thanks for reviewing!
Committed r258802: <https://trac.webkit.org/changeset/258802> All reviewed patches have been landed. Closing bug and clearing flags on attachment 393997 [details].