date();
    },

    context() {
      // This is a little weird here, but we have to be able to walk up the
      // parent tree to get the context.
      if (!Polymer.dom(this).parentNode) return undefined;

      if (!Polymer.dom(this).parentNode.context) {
        throw new Error('Parent container does not support context() method.');
      }
      return Polymer.dom(this).parentNode.context();
    },

    decorateChild_(childTrack) {
    },

    undecorateChild_(childTrack) {
      if (childTrack.detach