| /** |
| * @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 |
| */ |
| /** |
| * Checks whether the user's browser supports passive event listeners. |
| * See: https://github.com/WICG/EventListenerOptions/blob/gh-pages/explainer.md |
| */ |
| export declare function supportsPassiveEventListeners(): boolean; |
| /** |
| * Normalizes an `AddEventListener` object to something that can be passed |
| * to `addEventListener` on any browser, no matter whether it supports the |
| * `options` parameter. |
| * @param options Object to be normalized. |
| */ |
| export declare function normalizePassiveListenerOptions(options: AddEventListenerOptions): AddEventListenerOptions | boolean; |