as there are encryption schemes that preserve the payload structure
well enough and do not require those extensions.
This improves consistency as the webrtc-encoded-transform API
(which does not use this synchronous codepath) does not require those
header extensions either.
BUG=webrtc:12995
Change-Id: If237ca5d92e8871ac71c3d48fdd05127206395e6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226741
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34537}