Stores a view output in the elements.
protected function storeViewPreview($output) {
  $htmlDom = new \DOMDocument();
  @$htmlDom
    ->loadHTML($output);
  if ($htmlDom) {
    // It's much easier to work with simplexml than DOM, luckily enough
    // we can just simply import our DOM tree.
    $this->elements = simplexml_import_dom($htmlDom);
  }
}