Comment 9 for bug 1153137

Seb, I already suggested adding Enhances: chromium-browser to the extensions, if you want it installed by default in Unity, make it a recommends for unity, but please don't make non-unity users get it by default. Alternatively, make it a recommends of ubuntu-desktop if you like, but the chromium-browser package is not the place for the recommends.
Per the Policy section quoted in the description, not having unity installed shouldn't be called an unusual circumstance as it's one of the many DEs we have in the archive (we have 6 flavors shipping non-Unity DEs by default [Kubuntu, Lubuntu, Mythbuntu, Ubuntu Studio, Xubuntu, Ubuntu GNOME], only 2 flavors ship Unity by default [Ubuntu Desktop, Edubuntu].