This CL adds the encoder and wires it up to the event log.
Parser and unit tests are uploaded in a separate CL.
Bug: webrtc:8111
Change-Id: I6470003e55c2c4006cd8349a2c4bdc3f9491d869
Reviewed-on: https://webrtc-review.googlesource.com/c/106708
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Elad Alon <eladalon@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25333}