Code review comment for lp://qastaging/~fboucault/unity-2d/dash_preferred_apps_gio

The code looks good and functional tests are good (I tested switching my e-mail client from Evolution to Thunderbird, and my web browser between Chromium, Firefox and Opera).

Once the two previous remarks are addressed, this can be merged.

Question: what is missing to also migrate the other default applications (picture viewer and media player) to this new technique?