import { InjectionToken } from '@angular/core';
import { Observable } from 'rxjs';
/**
 * Injection token for an Observable based on `window.requestAnimationFrame`.
 *
 * This token provides an Observable that emits timestamps on each animation frame.
 * It utilizes the WINDOW injection token to access the requestAnimationFrame and cancelAnimationFrame
 * methods of the global window object. The Observable is shared to ensure multiple subscribers
 * receive the same animation frame updates.
 */
export declare const ANIMATION_FRAME: InjectionToken<Observable<number>>;