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)

* @return {?string} Rendered markup to be inserted into the DOM.
   * @final
   * @internal
   */
  mountComponent: function(
    transaction,
    nativeParent,
    nativeContainerInfo,
    context
  ) {
    this._context = context;
    this._mountOrder = nextMountID++;
    this._nativeParent = nativeParent;
    this._nativeContainerInfo = nativeContainerInfo;
    var publicProps = this._processProps(this._currentElement.props);
    var publicContext = this._processContext(context);
    var Component = this._currentElement.type;
    
    var inst = this._constructComponent(publicProps, publicContext);
    var renderedElement;
    
    if (!shouldConstruct(Component) && (inst == null || inst.render == null)) {
      renderedElement = inst;
      warnIfInvalidElement(Component, renderedElement);
      invariant(
        inst === null ||
        inst === false ||
        ReactElement.isValidElement(inst),
        '%s(...): A valid React element (or null) must be returned. You may have ' +
        'returned undefined, an array or some other invalid object.',