It doesn’t have a `@flow` annotation. We should start Flow-ifying it to avoid bugs like https://github.com/facebook/react/pull/11173.

@iamdustan Wanna take it?
return Component.prototype && Component.prototype.isReactComponent;
}
function getNonChildrenInnerMarkup(props) {
  var innerHTML = props.dangerouslySetInnerHTML;
  if (innerHTML != null) {
    if (innerHTML.__html != null) {
      return innerHTML.__html;
    }
  } else {
    var content = props.children;
    if (typeof content === 'string' || typeof content === 'number') {
      return escapeTextContentForBrowser(content);
    }
  }
  return null;
}
function flattenOptionChildren(children) {