startEndRange);
    const breakdownTree = tr.metrics.sh.generateWallClockTimeBreakdownTree(
        rendererHelper.mainThread, networkEvents, startEndRange);
    return breakdownTree;
  }

  function getCpuTimeBreakdownTree(rendererHelper, start, end) {
    const startEndRange = tr.b.math.Range.fromExplicitRange(start, end);
    const breakdownTree = tr.metrics.sh.generateCpuTimeBreakdownTree(
        rendererHelper.mainThread, startEndRange);
    return breakdownTree;
  }

  function persecondMetric(histog