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)

if (Component.propTypes) {
        this._checkPropTypes(
          Component.propTypes,
          newProps,
          ReactPropTypeLocations.prop
        );
      }
    }
    return newProps;
  },
  /**
   * Assert that the props are valid
   *
   * @param {object} propTypes Map of prop name to a ReactPropType
   * @param {object} props
   * @param {string} location e.g. "prop", "context", "child context"
   * @private
   */
  _checkPropTypes: function(propTypes, props, location) {
    
    
    var componentName = this.getName();
    for (var propName in propTypes) {
      if (propTypes.hasOwnProperty(propName)) {
        var error;
        try {
          
          
          invariant(
            typeof propTypes[propName] === 'function',