GitLab

This is a reland of ca8bb6e7

Original change's description:
> [Chromecast] Add support for mixer compatible CMA backend
>
> enable_video_with_mixed_audio gn flag has been added to turn on the new
> CMA backend.
>
> Created libcast_media_1.0_avsync, a target that implements this new CMA
> backend.
>
> AudioDecoderForMixer now owns an instance of a new interface, AvSync.
> AudioDecoderForMixer will notify AvSync of its current status, and
> AvSync will call into a new interface, VideoDecoderForMixer.
> VideoDecoderForMixer will give AvSync enough control over the video
> clock.
>
> BUG=internal 73746352
>
> Change-Id: Id7f991ec9606b6f04dbb68f819ad5bf1c3da9cce
> Reviewed-on: https://chromium-review.googlesource.com/947258
> Reviewed-by: Sergey Volk <servolk@chromium.org>
> Reviewed-by: Kenneth MacKay <kmackay@chromium.org>
> Commit-Queue: Mina Almasry <almasrymina@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#541293}

Bug: internal 73746352
Change-Id: I7bca4c61ec5ef0338116f57d235eb74fa88133b6
Reviewed-on: https://chromium-review.googlesource.com/952167Reviewed-by: Sergey Volk <servolk@chromium.org>
Commit-Queue: Mina Almasry <almasrymina@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541527}