GTK+ 3.11.3 was tagged today for the next GNOME 3.12 development build and with it the Wayland back-end is taking advantage of the new XDG-Shell support, which will be part of Wayland/Weston 1.4. This next major Wayland and Weston compositor release entered alpha today and should be officially released in mid-January.
Besides GTK+ 3.11.3 using the XDG-Shell on Wayland, the tool-kit update makes using client-side decorations more compatible with traditional desktop,s uses the GtkHeaderBar now, has new demos, and many bugs have been fixed.
More details on the changes for GTK+ 3.11.3 can be found via its Git commit tag. GNOME 3.11/3.12 development releases have already made further Wayland improvements than the experience found with the GNOME Shell 3.10 on Wayland. Stay tuned for new GNOME Wayland benchmarks in the days ahead.