20efdfcb41
Previously a grab could suddenly end without the grabber knowing anything about it. Some grabs assume they won't suddenly end without notice, and can use then new 'cancel' vfunc to be notified. Currently a grab is cancelled when a new one is started (i.e. in meta_wayland_pointer_grab_start()), when a non-popup compositor wide event route is initiated, and when the seat looses the pointer capability. https://bugzilla.gnome.org/show_bug.cgi?id=771858