focusRelevantElement_() {
    if (!this.getElement()) {
      return;
    }
    var textArea = /** @type {HTMLTextAreaElement} */
        (this.getElement().querySelector('textarea'));
    textArea.scrollTop = 0;
    textArea.setSelectionRange(0, 0);
    this.chipHolder_.focus();
    if (this.chipHolder_.hasChildren()) {
      // Double focus() workarounds a bug that prevents the caret from being
      // displayed in Chrome if setSelectionRange() is used.
      textArea.focus();
    }
  }
Puts the focus on the chip holder (if no user chips are present) or the
textarea.
@private