dEvents()) {
      if (hasTitleAndCategory(e, 'navigationStart', 'blink.user_timing')) {
        navStartTimestamps.push(e.start);
      }
    }
    return navStartTimestamps;
  }

  /**
   * Returns a map of renderer PIDs to array of timestamps at which the
   * renderer became interactive.
   */
  function getInteractiveTimestamps(model) {
    const interactiveTimestampsMap = new Map();
    const chromeHelper = model.getOrCreateHelper(
        tr.model.helpers.ChromeModelHelper);
    for (const rendererHe