This is a consistent way to get to common config parameters for all receive streams and avoids storing a copy of the extension headers inside of Call. This is needed to get rid of the need of keeping config and copies in sync, which currently is part of why we repeatedly delete and recreate audio receive streams on config changes. Bug: webrtc:11993 Change-Id: Ia356b6cac1425c8c6766abd2e52fdeb73c4a4b4f Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/222040 Commit-Queue: Tommi <tommi@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34285}