to list of extensions supported by RtpPacket. Bug: webrtc:9361 Change-Id: Iabee824381be3776e17e95f32507058607fc0bc8 Reviewed-on: https://webrtc-review.googlesource.com/85346 Reviewed-by: Philip Eliasson <philipel@webrtc.org> Reviewed-by: Alex Loiko <aleloi@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23788}