This means sender frames cloned from received frames have a valid header from the start, rather than callers needing to later call SetMetadata. Bug: webrtc:14708 Change-Id: Ie25fbd6609928a9555b6db688ab451ff61fa7147 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/293041 Reviewed-by: Stefan Holmer <stefan@webrtc.org> Commit-Queue: Tony Herre <herre@google.com> Reviewed-by: Tove Petersson <tovep@google.com> Cr-Commit-Position: refs/heads/main@{#39317}