ew Error('Internal Error: Unhandled endpoint type.');
      }
    }

    if (interactiveCandidate === undefined &&
        reachedTTIQuiscence_(searchEnd,
            networkQuietWindowStart, mainThreadQuietWindowStart)) {
      interactiveCandidate = mainThreadQuietWindowStart;
    }

    if (interactiveCandidate === undefined) return undefined;

    return Math.max(interactiveCandidate, domContentLoadedEnd);
  }

  /**
   * Returns the required quiet window size for First CPU Idle at
   * |timeSinceSearch