Polyfill web-animations-next-lite loading only on non Chrome browsers

[JosefJezek]

On Chrome have this polyfill unnecessarily size 15KB.

https://github.com/web-animations/web-animations-js

Load script on demand like as this code...

var webComponentsSupported = (
      'registerElement' in document
      && 'import' in document.createElement('link')
      && 'content' in document.createElement('template')
    );
    // Load webcomponentsjs polyfill if browser doesn't support native Web Components.
    if (!webComponentsSupported) {
      var script = document.createElement('script');
      script.async = true;
      script.src = 'bower_components/webcomponentsjs/webcomponents-lite.min.js';
      script.onload = onload;
      document.head.appendChild(script);
    }