This pull request just exists to have a place to put comments.  Please don't pull!

@myleshorton I don't think any STUN servers are hard-coded. 

Regarding using multiple STUN servers: I did some research, and it looks like support was very recently added (version 38.0.2125.54) https://code.google.com/p/webrtc/issues/detail?id=3310 so I think it's fine to pass in a list. 

Here's a list of public STUN servers I found https://code.google.com/p/natvpn/source/browse/trunk/stun_server_list