We used to throw if event listener is not a function in Stack:

```js
ReactDOM.render(
  <h1 onClick={{}}>Hello World!</h1>,
  document.getElementById('container')
);
```

<img width="565" alt="screen shot 2017-08-08 at 3 41 08 pm" src="https://user-images.githubusercontent.com/810438/29077502-2646412e-7c50-11e7-8c99-3b7f6c0a2589.png">

Fiber silently ignores this.

I think we should throw. This would let us add support for objects (e.g. for passive listener configuration) if we want to in a minor rather than a major.
ReactBrowserEventEmitter.trapBubbledEvent(
          'topLoad',
          'load',
          domElement,
        );
        props = rawProps;
        break;
      case 'video':
      case 'audio':
        
        for (var event in mediaEvents) {
          if (mediaEvents.hasOwnProperty(event)) {
            ReactBrowserEventEmitter.trapBubbledEvent(
              event,
              mediaEvents[event],
              domElement,
            );
          }
        }
        props = rawProps;
        break;
      case 'source':
        ReactBrowserEventEmitter.trapBubbledEvent(
          'topError',
          'error',
          domElement,
        );
        props = rawProps;
        break;
      case 'img':