Introduce set_hints event for xwayland

include/wlr/xwayland.h

@@ -150,6 +150,7 @@ struct wlr_xwayland_surface {
 		struct wl_signal set_parent;
 		struct wl_signal set_pid;
 		struct wl_signal set_window_type;
+		struct wl_signal set_hints;
 		struct wl_signal set_override_redirect;
 		struct wl_signal ping_timeout;
 	} events;

xwayland/xwm.c

@@ -154,6 +154,7 @@ static struct wlr_xwayland_surface *xwayland_surface_create(
 	wl_signal_init(&surface->events.set_parent);
 	wl_signal_init(&surface->events.set_pid);
 	wl_signal_init(&surface->events.set_window_type);
+	wl_signal_init(&surface->events.set_hints);
 	wl_signal_init(&surface->events.set_override_redirect);
 	wl_signal_init(&surface->events.ping_timeout);
 
@@ -492,6 +493,7 @@ static void read_surface_hints(struct wlr_xwm *xwm,
 	xsurface->hints_urgency = xcb_icccm_wm_hints_get_urgency(&hints);
 
 	wlr_log(WLR_DEBUG, "WM_HINTS (%d)", reply->value_len);
+	wlr_signal_emit_safe(&xsurface->events.set_hints, xsurface);
 }
 #else
 static void read_surface_hints(struct wlr_xwm *xwm,