src/vs/base/browser/ui/scrollbar/scrollbarVisibilityController.ts/ScrollbarVisibilityController/_hide
class ScrollbarVisibilityController:	private _hide(withFadeAway: boolean): void {
		this._revealTimer.cancel();
		if (!this._isVisible) {
			return;
		}
		this._isVisible = false;
		if (this._domNode) {
			this._domNode.setClassName(this._invisibleClassName + (withFadeAway ? ' fade' : ''));
		}
	}