facebook/flow — pull request #146 by k-bx (2014-11-28 23:13:38+00:00)
Title: Fix type of websocket event

You usually work with websockets like this:

```
var ws = new WebSocket();
ws.onmessage = function(event) {
console.log(event.data);
}
```

Previously flow would error that `event.data` property is not defined.