static _setRecursiveEmptyAttributableURLs(task, urls) {
    // If this task had any attributableURLs, its children will too, so we can stop here.
    if (task.attributableURLs.length) return;

    task.attributableURLs = urls.slice();
    task.children.forEach(child =>
      MainThreadTasks._setRecursiveEmptyAttributableURLs(
        child,
        urls
      )
    );
  }
@param {TaskNode} task
@param {Array<string>} urls