xwayland: add set_geometry event

This is necessary to react to changes in position of override-redirect
views.

include/wlr/xwayland.h

@@ -198,6 +198,7 @@ struct wlr_xwayland_surface {
 		struct wl_signal set_hints;
 		struct wl_signal set_decorations;
 		struct wl_signal set_override_redirect;
+		struct wl_signal set_geometry;
 		struct wl_signal ping_timeout;
 	} events;
 

xwayland/xwm.c

@@ -164,6 +164,7 @@ static struct wlr_xwayland_surface *xwayland_surface_create(
 	wl_signal_init(&surface->events.set_decorations);
 	wl_signal_init(&surface->events.set_override_redirect);
 	wl_signal_init(&surface->events.ping_timeout);
+	wl_signal_init(&surface->events.set_geometry);
 
 	xcb_get_geometry_reply_t *geometry_reply =
 		xcb_get_geometry_reply(xwm->xcb_conn, geometry_cookie, NULL);
@@ -935,15 +936,25 @@ static void xwm_handle_configure_notify(struct wlr_xwm *xwm,
 		return;
 	}
 
+	bool geometry_changed =
+		(xsurface->x != ev->x || xsurface->y != ev->y ||
+		 xsurface->width != ev->width || xsurface->height != ev->height);
+
+	if (geometry_changed) {
 		xsurface->x = ev->x;
 		xsurface->y = ev->y;
 		xsurface->width = ev->width;
 		xsurface->height = ev->height;
+	}
 
 	if (xsurface->override_redirect != ev->override_redirect) {
 		xsurface->override_redirect = ev->override_redirect;
 		wlr_signal_emit_safe(&xsurface->events.set_override_redirect, xsurface);
 	}
+
+	if (geometry_changed) {
+		wlr_signal_emit_safe(&xsurface->events.set_geometry, NULL);
+	}
 }
 
 #define ICCCM_WITHDRAWN_STATE	0