olling content
      // was reached. This means that calling scroll({top: 0, behavior: 'silent'}) when
      // the momentum is still going will result in more scroll events and thus scroll effects.
      // This seems to only apply when using document scrolling.
      // Therefore, when should we remove the class from the document element?

      window.cancelAnimationFrame(Polymer.AppLayout._scrollTimer);

      Polymer.AppLayout._scrollTimer = window.requestAnimationFrame(function() {
        headers.for