GitLab

1. remove tune() from VideoEncoder
2. Remove promises from VideoEncoder
3. Split init and config

Bug: 1094166
Change-Id: I47b347c89bb11991cdd61f52e0e4a7ce99b8b1d6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2244660Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Eugene Zemtsov <eugene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779871}