Remove explicit `document` receiver from add/removeEventListener calls

This allows ActionCable to be used in a web worker, where the `document`
global is undefined. Previously, attempting to use ActionCable inside a
web worker would result in this exception after you try to open a
connection:
```
ReferenceError: document is not defined
```

The visibilitychange event won't ever get triggered in a worker, so
adding the listener is effectively a no-op there. But the listener is
mainly a convenience, rather than a critical piece of the javascript
interface, so using ActionCable in a worker will still work. (And you
could listen for visibilitychange yourself in a window script, then tell
the worker to reconnect if you still want that behavior.)

0 files changed, 0 insertions, 0 deletions