Determine if two URLs share the same origin.

@param {string|Object} url1 - First URL to compare as a string or a normalized URL in the form of
a dictionary object returned by `urlResolve()`.
@param {string|object} url2 - Second URL to compare as a string or a normalized URL in the form
of a dictionary object returned by `urlResolve()`.

@returns {boolean} - True if both URLs have the same origin, and false otherwise.
function urlsAreSameOrigin(url1, url2) {
  url1 = urlResolve(url1);
  url2 = urlResolve(url2);

  return (url1.protocol === url2.protocol &&
          url1.host === url2.host);
}