src/vs/base/common/scrollable.ts/Scrollable/constructor
class Scrollable:	constructor(smoothScrollDuration: number, scheduleAtNextAnimationFrame: (callback: () => void) => IDisposable) {
		super();

		this._smoothScrollDuration = smoothScrollDuration;
		this._scheduleAtNextAnimationFrame = scheduleAtNextAnimationFrame;
		this._state = new ScrollState(0, 0, 0, 0, 0, 0);
		this._smoothScrolling = null;
	}