As of today WebRTC is the only project that can use Abseil in Chromium because Abseil doesn't mark symbols as exported and this complicates the component build support (there is a small exception for openscreen since they need to use things without globals but aside from that visibility is locked down, see
here).
I have been discussing with Abseil about this but lately I have been busy trying to finish the WebRTC component build support. On top of that there are other issues dcheng@ was working on (also gab@ has context on that).