static render(dom, details, detailsRenderer) {
    const tmpl = dom.createComponent('snippet');
    const snippetEl = dom.find('.lh-snippet', tmpl);

    const header = SnippetRenderer.renderHeader(
      dom,
      details,
      detailsRenderer,
      () => snippetEl.classList.toggle('lh-snippet--expanded')
    );
    const content = SnippetRenderer.renderSnippetContent(dom, tmpl, details);
    snippetEl.append(header, content);

    return snippetEl;
  }
@param {DOM} dom
@param {LH.Audit.Details.SnippetValue} details
@param {DetailsRenderer} detailsRenderer
@return {!Element}