Also delete the method RTPPayloadRegistry::red_payload_type() and
remnants of RED support in RTPReceiverAudio.
Bug: webrtc:8995,webrtc:5922
Change-Id: Iee310f5a8628ba70942e8c0277a856d2ca1f9b35
Reviewed-on: https://webrtc-review.googlesource.com/61500
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22425}