Change WebRtcSession to have a vector of channels
This is the first step towards supporting multiple audio/video
channels in PeerConnection/WebRtcSession. For now, there can only
be 0 or 1 channels in the vector. This adds the framework so that
all the other code that assumes a single audio/video channel can
be transitioned one-by-one to multiple channels.
Bug: webrtc:8183
Change-Id: I6456af32d6e3adf7eb83e281e43253ea973c4eb9
Reviewed-on: https://chromium-review.googlesource.com/644222
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Original-Commit-Position: refs/heads/master@{#19615}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 169629aca3140803731af3d586932ffc176bed462 files changed
