Method getPreconnects

src/base-element.js:219–221

* Called by the framework to give the element a chance to preconnect to * hosts and prefetch resources it is likely to need. May be called * multiple times because connections can time out. * * Returns an array of URLs to be preconnected. * * @param {!AmpElement} unusedElement *

(unusedElement)

   *
   */
  static getPreconnects(unusedElement) {
    return null;
  }

  /**
   * Subclasses can override this method to indicate that instances need to