We missed this because Flow wasn't being run properly on Travis but now that it is, it's clear that #7716 introduced a bunch of new Flow failures. Most of these shouldn't be too bad and I like to say "you break it you buy it" so this one is for you @Aweary :)

There were a couple other pre-existing Flow issues that @vjeux is going to fix, so mostly this should just be the TestRenderer issues.

}
    if (!this._hostParent) {
      ret += ' ' + DOMPropertyOperations.createMarkupForRoot();
    }
    ret += ' ' + DOMPropertyOperations.createMarkupForID(this._domID);
    return ret;
  },
  /**
   * Creates markup for the content between the tags.
   *
   * @private
   * @param {ReactReconcileTransaction|ReactServerRenderingTransaction} transaction
   * @param {object} props
   * @param {object} context
   * @return {string} Content markup.
   */
  _createContentMarkup: function(transaction, props, context) {
    var ret = '';
    
    var innerHTML = props.dangerouslySetInnerHTML;
    if (innerHTML != null) {
      if (innerHTML.__html != null) {
        ret = innerHTML.__html;
      }
    } else {
      var contentToUse =
        CONTENT_TYPES[typeof props.children] ? props.children : null;
      var childrenToUse = contentToUse != null ? null : props.children;
      if (contentToUse != null) {