/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import { OverlayReference } from '../overlay-reference';
/**
 * Describes a strategy that will be used by an overlay to handle scroll events while it is open.
 */
export interface ScrollStrategy {
    /** Enable this scroll strategy (called when the attached overlay is attached to a portal). */
    enable: () => void;
    /** Disable this scroll strategy (called when the attached overlay is detached from a portal). */
    disable: () => void;
    /** Attaches this `ScrollStrategy` to an overlay. */
    attach: (overlayRef: OverlayReference) => void;
    /** Detaches the scroll strategy from the current overlay. */
    detach?: () => void;
}
/**
 * Returns an error to be thrown when attempting to attach an already-attached scroll strategy.
 */
export declare function getMatScrollStrategyAlreadyAttachedError(): Error;