[heycam/webidl] Indicate that thing needs user action to work (#137)

There are things in the platform that can only succeed because of some user action. For example, directly calling:

```JS
document.body.requestFullscreen();
```

In Gecko, results in the following warning:

```
⚠️  Request for fullscreen was denied because Element.requestFullscreen() was not called from inside a short running user-generated event handler.
```

Would it be useful to have some means of annotating such behavior using WebIDL?

---
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/heycam/webidl/issues/137