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.

processQueue(this, updates);
  },
  /**
   * Updates the rendered children with new children.
   *
   * @param {?object} nextNestedChildrenElements Nested child element maps.
   * @param {ReactReconcileTransaction} transaction
   * @internal
   */
  updateChildren: function(nextNestedChildrenElements, transaction, context) {
    
    this._updateChildren(nextNestedChildrenElements, transaction, context);
  },
  /**
   * @param {?object} nextNestedChildrenElements Nested child element maps.
   * @param {ReactReconcileTransaction} transaction
   * @final
   * @protected
   */
  _updateChildren: function(nextNestedChildrenElements, transaction, context) {
    var prevChildren = this._renderedChildren;
    var removedNodes = {};
    var mountImages = [];
    var nextChildren = this._reconcilerUpdateChildren(
      prevChildren,
      nextNestedChildrenElements,
      mountImages,
      removedNodes,
      transaction,
      context