chromium/ui/webui/resources/images/add.svg

<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24"><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/><path d="M0 0h24v24H0z" fill="none"/></svg>