Es un "web Component" para hacer un campo select que ya viene poblado con los países del mundo.
bower install dw-countries-select
Poder usar este componente requiere de dos pasos:
<link rel="import" href="bower_components/dw-countries-select/dw-countries-select.html">
<select name="pais" is="dw-countries-select"></select>
You may also enter additional options in the HTML code of the component.
<select is="dw-countries-select">
<option value="-">Select your country</option>
</select>