+/**
+ * Add the sidebar toggle button.
+ *
+ * @since 3.8.0
+ *
+ * @param WP_Admin_Bar $wp_admin_bar
+ */
+function wp_admin_bar_sidebar_toggle( $wp_admin_bar ) {
+ if ( is_admin() ) {
+ $wp_admin_bar->add_menu( array(
+ 'id' => 'menu-toggle',
+ 'title' => '<span class="ab-icon"></span>',
+ 'href' => '#',
+ 'meta' => array(
+ 'title' => __( 'Menu' ),
+ ),
+ ) );
+ }
+}
+