Comment 13 for bug 779382

One way to do it would be to restrict the new codepath to unity, checking XDG_CURRENT_DESKTOP=Unity (which gnome-session sets to this value for unity and unity-2d sessions), in other patches we use that variable already to display unity specific uis and fallbacking to the current code in non-Unity session

The changes are non trivial though so we should probably go with a SRU which let extra margins for testing and is less risky, the current whitelisting solution hit an unity rendering issue but that should be fixed in an unity SRU and only affect users who tweaked their config, no the default installation