Ranges, rangeOfInterest);
    const totalFreeDuration = tr.b.math.Statistics.sum(idleRanges,
        range => range.duration);
    breakdownTree.idle = {total: totalFreeDuration, events: {}};

    let totalBlockedDuration = rangeOfInterest.duration;
    for (const [title, component] of Object.entries(breakdownTree)) {
      // v8_runtime is a subcategory of script_execute.
      // See github.com/catapult-project/catapult/commit/f3881d commit message.
      // TODO(#2572) Make user friendly category hierarc