The meta_wayland_surface_hide_inhibit_shortcuts_dialog() function
disconnected the "destroy" handler, but we'd still be listening on
response events. Change this to just hide the dialog, leaving the data
intact with the proper life time signal in place.
https://bugzilla.gnome.org/show_bug.cgi?id=786385
The 'data' object is attached to the MetaWaylandSurface as a GObject
qdata. It is created once, and stays allocated until the surface is
destroyed. To make things clearer, connect to the "destroy" signal just
after creating, and from a on_surface_destroyed() callback call the
.._free() function.
https://bugzilla.gnome.org/show_bug.cgi?id=786385
Plug the new MetaInhbitShortcutsDialog to the relevant Wayland protocol
implementation.
Also, remember the last user choice for a given surface to avoid asking
continuously the same question.
https://bugzilla.gnome.org/show_bug.cgi?id=783342
