AppController: The controller that connects the UI and the model "Call". It owns Call, InfoBox and RoomSelection.
Call: Manages everything needed to make a call. It owns SignalingChannel and PeerConnectionClient.
SignalingChannel: Wrapper of the WebSocket connection.
PeerConnectionClient: Wrapper of RTCPeerConnection.
InfoBox: Wrapper of the info div utilities.
RoomSelection: Wrapper for the room selection UI. It owns Storage.
Storage: Wrapper for localStorage/Chrome app storage API.