Hello,
I'm not using gnome but when dist-upgrading today apt-listbugs pointed me to this:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=718552
I was hit by this bug.:oops:
For me gnome-shell=3.4.2-12 seems to make it working again :D
For some reason gnome-shell works for me as some extensions provide dbus.js. If you have no extensions installed then you certainly might be hit by this bug.
It seems it was fixed this morning.