WebRtcVideoChannel and and WebRtcVideoEngine seem to have been removed, and only WebRtcVideoChannel2 and WebRtcVideoEngine2 remain, which removes the need for the "2" postfix. BUG=None Review-Url: https://codereview.webrtc.org/2932073002 Cr-Commit-Position: refs/heads/master@{#18531}