Confirmed fixed with chromium-browser 81.0.4044.129-0ubuntu0.19.10.1 from eoan-proposed.
I verified chromium-browser didn't appear in the list of reverse provides for x-www-browser and gnome-www-browser in a fully up-to-date eoan VM, then I enabled eoan-proposed for universe, ran "apt update", and verified that it did appear for both.
Confirmed fixed with chromium-browser 81.0.4044. 129-0ubuntu0. 19.10.1 from eoan-proposed.
I verified chromium-browser didn't appear in the list of reverse provides for x-www-browser and gnome-www-browser in a fully up-to-date eoan VM, then I enabled eoan-proposed for universe, ran "apt update", and verified that it did appear for both.