The purose of this cl is to remove dependency on cricket::VideoCapturer from WebRtcVideoChannel2.
This cl change CPU adaptation to use a new VideoSinkWants.Resolution
Cl is WIP and uploaded to start the discussion.
Tested on a N5 with hw acceleration turned off.
BUG=webrtc:5426
Review URL: https://codereview.webrtc.org/1695263002
Cr-Commit-Position: refs/heads/master@{#11804}