add xwayland unmanaged tests to support dmenu

This adds `wlr_xwayland_surface_is_unamanged`, to allow compositors more
fine grained control over XWayland focus.
A surface that is unmanaged should not receive focus, while other
windows that are just override redirect may want it (dmenu).
The way unamanged is determined is taken from wlc.

xwayland/xwayland.c

@@ -405,3 +405,24 @@ void wlr_xwayland_set_seat(struct wlr_xwayland *xwayland,
 	xwayland->seat_destroy.notify = wlr_xwayland_handle_seat_destroy;
 	wl_signal_add(&seat->events.destroy, &xwayland->seat_destroy);
 }
+
+
+bool wlr_xwayland_surface_is_unmanaged(const struct wlr_xwayland_surface *surface) {
+	static enum atom_name needles[] = {
+		NET_WM_WINDOW_TYPE_UTILITY,
+		NET_WM_WINDOW_TYPE_TOOLTIP,
+		NET_WM_WINDOW_TYPE_DND,
+		NET_WM_WINDOW_TYPE_DROPDOWN_MENU,
+		NET_WM_WINDOW_TYPE_POPUP_MENU,
+		NET_WM_WINDOW_TYPE_COMBO,
+	};
+
+	for (size_t i = 0; i < sizeof(needles) / sizeof(needles[0]); ++i) {
+		if (wlr_xwm_atoms_contains(surface->xwm, surface->window_type,
+				surface->window_type_len, needles[i])) {
+			return true;
+		}
+	}
+
+	return false;
+}