Facebook's plan to revive its public group chat feature just became official. The social network tells the Courier Mail that it's rolling out a test version of Messenger Rooms on Android devices in Australia and Canada. As leaked code suggested, this is similar to but not quite like the Rooms app of old. All you have to do is create (or search for) a room around a given topic -- after that, anyone can join. If you're worried that you'll get an influx of trolls, you can require approval for new participants.