Otherwise, we fall back to standard HTML templates, which do not have
      // any sort of binding support.
      } else {
        if (model) {
          console.warn(this, 'was given a model to stamp, but the template is not of a bindable type');
        }

        stamped = document.importNode(fixtureTemplate.content, true);

        // Immediately upgrade the subtree if we are dealing with async
        // Web Components polyfill.
        // https://github.com/Polymer/polymer/blob/0.8-preview/src/feature