    ];

      // Discard elements with tabindex=-1 (makes them not focusable).
      var selector = FOCUSABLE_WITH_DISABLED.join(':not([tabindex="-1"]),') +
        ':not([tabindex="-1"]),' +
        FOCUSABLE_WITHOUT_DISABLED.join(':not([disabled]):not([tabindex="-1"]),') +
        ':not([disabled]):not([tabindex="-1"])';

      var focusables = Polymer.dom(this).querySelectorAll(selector);
      if (this.tabIndex >= 0) {
        // Insert at the beginning because we might have all elements with tabIndex =