How To Install GTK3 With Broadway (HTML5) Backend Enabled In Ubuntu

Starting with version 3.2, GTK+ comes with an experimental "Broadway" backend that allows rendering GTK3 applications in HTML5-capable browsers, so you can run applications remotely, using only a web browser.
Ubuntu doesn't enable this Broadway backend by default, but thanks to Nicolas Delvaux's PPA, you can easily give this a try in Ubuntu 13.04, 12.10 or 12.04.