Chrome iOS won't load new scenes

**Describe the bug**

Chrome on iOS - notably _not_ Safari on iOS - won't load new scenes. (I presume this is actually to do with the underlying webview that Chrome has to use.)

**To Reproduce**

1. Open Santa Tracker in Chrome on iOS
2. Try to load another game or scene
3. Wait and see the timeout

**Notes**

This is new in 2021.

Basically we try to load another `` but never receive its hello payload (every scene that starts up posts a port to its parent) or see it render on the screen.

If you kill the previous frame immediately (rather than letting it stick around for a bit), _sometimes_ it will load. My hunch is that iOS is severely limiting the number of frames that are allowed. The lifecycle around killing the previous frame is a bit nebulous though (even though I wrote it) - I'd suggest maybe taking a fresh look at in future.

The solution is: not sure. The entire architecture of Santa today leverages "disposable" cross-domain iframes to load games, which has worked pretty well for us.