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.
var ReactDOMFiberSelect = require('ReactDOMFiberSelect');
var ReactDOMFiberTextarea = require('ReactDOMFiberTextarea');
var {getCurrentFiberOwnerName} = require('ReactDebugCurrentFiber');
var {DOCUMENT_NODE, DOCUMENT_FRAGMENT_NODE} = require('HTMLNodeType');
var assertValidProps = require('assertValidProps');
var emptyFunction = require('fbjs/lib/emptyFunction');
var inputValueTracking = require('inputValueTracking');
var isCustomComponent = require('isCustomComponent');
var setInnerHTML = require('setInnerHTML');
var setTextContent = require('setTextContent');
if (__DEV__) {
  var warning = require('fbjs/lib/warning');
  var ReactDOMInvalidARIAHook = require('ReactDOMInvalidARIAHook');
  var ReactDOMNullInputValuePropHook = require('ReactDOMNullInputValuePropHook');
  var ReactDOMUnknownPropertyHook = require('ReactDOMUnknownPropertyHook');
  var {validateProperties: validateARIAProperties} = ReactDOMInvalidARIAHook;
  var {
    validateProperties: validateInputPropertes,
  } = ReactDOMNullInputValuePropHook;
  var {
    validateProperties: validateUnknownPropertes,
  } = ReactDOMUnknownPropertyHook;
}
var didWarnInvalidHydration = false;
var didWarnShadyDOM = false;
var listenTo = ReactBrowserEventEmitter.listenTo;
var registrationNameModules = EventPluginRegistry.registrationNameModules;
var DANGEROUSLY_SET_INNER_HTML = 'dangerouslySetInnerHTML';
var SUPPRESS_CONTENT_EDITABLE_WARNING = 'suppressContentEditableWarning';
var CHILDREN = 'children';