feat(layout): add deferred layout recalculation

examples/scroll/lv_example_scroll_3.c

@@ -11,8 +11,13 @@ static void float_btn_event_cb(lv_obj_t * float_btn, lv_event_t e)
         lv_snprintf(buf, sizeof(buf), "Track %d", btn_cnt);
         lv_obj_t * list_btn = lv_list_add_btn(list, LV_SYMBOL_AUDIO, buf, NULL);
         btn_cnt++;
-        lv_obj_scroll_to_view(list_btn, LV_ANIM_ON);
+
         lv_obj_move_foreground(float_btn);
+
+        /* Layouts are only recalculated later but we need to know the updated position of the new button
+         * to scroll to it. */
+        lv_obj_update_layout(list);
+        lv_obj_scroll_to_view(list_btn, LV_ANIM_ON);
     }
 }