constructor(
   public _intl: MatStepperIntl,
   private _focusMonitor: FocusMonitor,
   private _element: ElementRef<HTMLElement>,
   changeDetectorRef: ChangeDetectorRef) {
   _focusMonitor.monitor(_element.nativeElement, true);
   this._intlSubscription = _intl.changes.subscribe(() => changeDetectorRef.markForCheck());
 }

 constructor(private _focusMonitor: FocusMonitor, private _element: ElementRef) {
   _focusMonitor.monitor(_element.nativeElement, true);
 }

 constructor(
   private _focusMonitor: FocusMonitor,
   private _element: ElementRef,
   renderer: Renderer2) {
   _focusMonitor.monitor(_element.nativeElement, renderer, true);
 }

 ngOnDestroy() {
   this._intlSubscription.unsubscribe();
   this._focusMonitor.stopMonitoring(this._elementRef);
 }

 ngOnDestroy() {
   this._focusMonitor.stopMonitoring(this._element.nativeElement);
 }

 /** Focuses the step header. */
 focus() {
   this._focusMonitor.focusVia(this._elementRef, 'program');
 }