This method was unused. When deleted, also configuration of
receive-side RTP header extensions in this class becomes unused.
Header extensions are parsed in Call.
Bug: None
Change-Id: Iad76abf72962f3d91e85dde43541c3b6a9522b7e
Reviewed-on: https://webrtc-review.googlesource.com/39782
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21636}
90ea504f13