This is a step toward simplifying the VideoCodec struct and removing the targetBitrate. The hard-coded values now reside in SimulcastRateAllocator. A follow-up will do away with the field altogether. Bug: webrtc:9504 Change-Id: I74d483682309d363048fbbbd31e0607d7242f504 Reviewed-on: https://webrtc-review.googlesource.com/87424 Reviewed-by: Rasmus Brandt <brandtr@webrtc.org> Commit-Queue: Erik Språng <sprang@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23876}