unction, then it will be called when this link is
   * clicked or mouse-entered, and its result will be dispatched to this
   * link's embedder via a RequestSelectionChangeEvent.
   *
   * @param {*|function():*} selection
   */
  set selection(selection) {
    this.selection_ = selection;
    Polymer.dom(this).textContent = selection.userFriendlyName;
  },

  setSelectionAndContent(selection, opt_textContent) {
    this.selection_ = selection;
    if (opt_textContent) {
      Polymer.dom(this).textContent 