function findRootContainerNode(inst) {
  // TODO: It may be a good idea to cache this to prevent unnecessary DOM
  // traversal, but caching is difficult to do correctly without using a
  // mutation observer to listen for all DOM changes.
  while (inst.return) {
    inst = inst.return;
  }
  if (inst.tag !== HostRoot) {
    // This can happen if we're in a detached tree.
    return null;
  }
  return inst.stateNode.containerInfo;
}