Hello,

After updating to React 15.0.1, we are getting the following error:

```
Uncaught TypeError: Cannot read property 'addEventListener' of null
```

![image](https://cloud.githubusercontent.com/assets/4996164/14602577/5bb4e9f2-0571-11e6-9aa1-98de49f50d76.png)

* is exposed by refs and returned by render. Can be null for stateless
   * components.
   *
   * @return {ReactComponent} the public component instance.
   * @internal
   */
  getPublicInstance: function() {
    var inst = this._instance;
    if (inst instanceof StatelessComponent) {
      return null;
    }
    return inst;
  },
  
  _instantiateReactComponent: null,
};
ReactPerf.measureMethods(
  ReactCompositeComponentMixin,
  'ReactCompositeComponent',
  {
    mountComponent: 'mountComponent',
    updateComponent: 'updateComponent',
    _renderValidatedComponent: '_renderValidatedComponent',
  }
);
var ReactCompositeComponent = {
  Mixin: ReactCompositeComponentMixin,
};
module.exports = ReactCompositeComponent;