If the compositor supports the gtk-shell interface, use it to
export the application ID, dbus name and paths that can be used
for the application menu.
https://bugzilla.gnome.org/show_bug.cgi?id=707129
Allow to set a GdkWindow to use a custom surface instead of a
wl_shell_surface. It allows to register the surface as a custom type
with some Wayland interface.
https://bugzilla.gnome.org/show_bug.cgi?id=695861
Allows to access Wayland specific window information like wl_surface and
wl_shell_surface.
Add gdk_wayland_window_get_wl_surface for getting the Wayland wl_surface
and gdk_wayland_window_get_wl_shell_surface for getting the Wayland
wl_shell_surface.
