Consider moving the message list out of a overflow: scroll div

[davidben]

It makes me sad as far as layering goes, but would solve the current focusing problem. It also doesn't seem like Chrome knows to composite them yet? But they should fix that, and they seem to be working on it...

[davidben]

Yeah, I think I want to do this. The scrollbar should be at the edge anyway.

[davidben]

One complication is that the bounds of the container are now less obvious. This should hopefully be just a matter of replacing all the this.container_.getBoundingClientRect calls with a callback or something. Also loadingAbove_ when loaded will be more complex.

Seriously, can we just replace those two with Angular chunks? I'd like to replace the messages themselves with Angular chunks, certainly. The main complexity is that I need control over when they actually update to fix up the scroll. Maybe some sort of delayed-update directive?