src/vs/base/browser/ui/scrollbar/scrollbarVisibilityController.ts/ScrollbarVisibilityController/constructor
class ScrollbarVisibilityController:	constructor(visibility: ScrollbarVisibility, visibleClassName: string, invisibleClassName: string) {
		super();
		this._visibility = visibility;
		this._visibleClassName = visibleClassName;
		this._invisibleClassName = invisibleClassName;
		this._domNode = null;
		this._isVisible = false;
		this._isNeeded = false;
		this._rawShouldBeVisible = false;
		this._shouldBeVisible = false;
		this._revealTimer = this._register(new TimeoutTimer());
	}