Do I need to load the web component polyfill?

gistfile1.txt

if ('registerElement' in document
    && 'import' in document.createElement('link')
    && 'content' in document.createElement('template')) {
  // browser has web components
} else {
  // polyfill web components
  var e = document.createElement('script');
  e.src = 'bower_components/webcomponentsjs/webcomponents-lite.min.js';
  document.head.appendChild(e);
}