RTPFragmentationHeader is already ignored by H264 packetizer and thus doesn't need to be provided and calculated. Bug: webrtc:6471 Change-Id: I45bc22827f0dc811457e3ebe477a16293501c2fb Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/179843 Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Reviewed-by: Marco Paniconi <marpan@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#31791}