decorateInternal(element) {
    super.decorateInternal(element);
    if (!this.getLabelText()) {
      this.setLabelText(this.initialLabel_);
    }

    const elem = this.getElement();
    goog.dom.classlist.add(elem, goog.getCssName('goog-sample-component'));
    elem.style.backgroundColor = this.color_;
    elem.tabIndex = 0;

    this.kh_ = new goog.events.KeyHandler(elem);
    this.getHandler().listen(
        this.kh_, goog.events.KeyHandler.EventType.KEY, this.onKey_);
  }
Decorates an existing HTML DIV element as a SampleComponent.

@param {Element} element The DIV element to decorate. The element's
   text, if any will be used as the component's label.
@override
@suppress {strictMissingProperties} missing tabIndex prop