This CL takes a few parts of VCMEncodedFrameCallback and
VCMGenericEncoder and folds some aspect directly into
VideoStreamEncoder. Parts related to timing frames are extracted
into a new class FrameEncodeTimer that explicitly handles that.
Bug: webrtc:10164
Change-Id: I9b26f734473b659e4093c84c09fb0ed441290e40
Reviewed-on: https://webrtc-review.googlesource.com/c/124122
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26862}
