This is in preparation for moving the assignment of PT numbers to a different place. Bug: webrtc:42226302 Change-Id: I821f2b6b15eb9f9f3715714e2c2c220c5e5a219e Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/352921 Commit-Queue: Harald Alvestrand <hta@webrtc.org> Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org> Reviewed-by: Florent Castelli <orphis@webrtc.org> Cr-Commit-Position: refs/heads/main@{#42422}