import { Constructor } from '../utilities.js';
export interface OptionalLifecycleCallbacks {
    connectedCallback?(): void;
    disconnectedCallback?(): void;
}
export declare type MixableBaseClass = HTMLElement & OptionalLifecycleCallbacks;
/**
 * This mixin function is designed to be applied to a class that inherits
 * from HTMLElement. It makes it easy for a custom element to coordinate with
 * the :focus-visible polyfill.
 *
 * NOTE(cdata): The code here was adapted from an example proposed with the
 * introduction of ShadowDOM support in the :focus-visible polyfill.
 *
 * @see https://github.com/WICG/focus-visible/pull/196
 * @param {Function} SuperClass The base class implementation to decorate with
 * implementation that coordinates with the :focus-visible polyfill
 */
export declare const FocusVisiblePolyfillMixin: <T extends Constructor<MixableBaseClass, object>>(SuperClass: T) => T;