

<link rel="import" href="boot.html">

<script>

(function() {

  'use strict';

  // run a callback when HTMLImports are ready or immediately if
  // this api is not available.
  function whenImportsReady(cb) {
    if (window.HTMLImports) {
      HTMLImports.whenReady(cb);
    } else {
      cb();
    }
  }

  /**
   * Convenience method for importing an HTML document imperatively.
   *
   * This method creates a new `<link rel="import">` element with
   * the provided URL and appends it to the document t