libweston-desktop: Implement xdg_shell_v6

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>
Acked-by: Giulio Camuffo <giulio.camuffo@kdab.com>

Differential Revision: https://phabricator.freedesktop.org/D1210
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 98c5bd6..24cfcfa 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -3344,6 +3344,12 @@
 	return -1;
 }
 
+WL_EXPORT const char *
+weston_surface_get_role(struct weston_surface *surface)
+{
+	return surface->role_name;
+}
+
 WL_EXPORT void
 weston_surface_set_label_func(struct weston_surface *surface,
 			      int (*desc)(struct weston_surface *,