          </dd>
            <dt id="permission" class="property">
                <span class="top-level-variable-type">String</span>
                <a href="polymer_app_layout/Notification/permission.html">permission</a>
            </dt>
            <dd>
                <div class="readable-writable">
        read-only
    </div>
    
            </dd>
            <dt id="tag" class="property">
                <span class="top-level-variable-type">String</span>
                <a href="polymer_app_layout