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.

receiveComponent: function(nextComponent, transaction, context) {
    const props = nextComponent.props;
    const oldProps = this._currentElement.props;
    this.applyGroupProps(oldProps, props);
    this.updateChildren(props.children, transaction, context);
    this._currentElement = nextComponent;
  },
  applyGroupProps: function(oldProps, props) {
    this.node.width = props.width;
    this.node.height = props.height;
    this.applyNodeProps(oldProps, props);
  },
  unmountComponent: function() {
    this.destroyEventListeners();
    this.unmountChildren();
  }
});
const ClippingRectangle = createComponent(
    'ClippingRectangle', NodeMixin, ContainerMixin, {
  mountComponent: function(
    transaction,
    nativeParent,
    nativeContainerInfo,
    context
  ) {
    this.node = Mode.ClippingRectangle();
    const props = this._currentElement.props;
    this.applyClippingProps(emptyObject, props);
    this.mountAndInjectChildren(props.children, transaction, context);
    return this.node;