ed: function() {
      // We don't really need property effects on these, and also we want them
      // to be created before the `_parentResizable` observer fires:
      this._interestedResizables = [];
      this._boundNotifyResize = this.notifyResize.bind(this);
    },

    attached: function() {
      this.fire('iron-request-resize-notifications', null, {
        node: this,
        bubbles: true,
        cancelable: true
      });

      if (!this._parentResizable) {
        window.addEventListener('re