code: function() {
        // Find element with `autofocus` attribute, or fall back to the first form/tabindex control.
        var target = this.dialog_.querySelector('[autofocus]:not([disabled])');
        if (!target && this.dialog_.tabIndex >= 0) {
          target = this.dialog_;
        }
        if (!target) {
          // Note that this is 'any focusable area'. This list is probably not exhaustive, but the
          // alternative involves stepping through and trying to focus everything.
          var opts = ['button', 'input', 'keygen', 'select', 'textarea'];
          var query = opts.map(function(el) {
            return el + ':not([disabled])';
          });
          // TODO(samthor): tabindex values that are not numeric are not focusable.
          query.push('[tabindex]:not([disabled]):not([tabindex=""])');  // tabindex != "", not disabled
          target = this.dialog_.querySelector(query.join(', '));
        }
        safeBlur(document.activeElement);
        target && target.focus();
      }
docs: Focuses on the first focusable element within the dialog. This will always blur the current
  focus, even if nothing within the dialog is found.