media: Implement zero-copy video playback for ffmpeg.

media: Implement zero-copy video playback for ffmpeg.

Current zero-copy video playback implementation is actually "one-copy video playback".
The final VideoFrame is produced by following pipeline.
1. FFmpeg decoder produces a VideoFrame.
2. GpuMemoryBufferVideoFramePool copies the software VideoFrame to hardware VideoFrame backed by GpuMemoryBuffer.
3. CC composites the mailbox belonging to hardware VideoFrame.

This CL gets rid of #2 step. FFmpegVideoDecoder will decode video frame
directly on hardware VideoFrame backed by GpuMemoryBuffer.

This CL supports only I420, YV12 and YV12A.

TODO: support more YUV planes.
Dependency: 
1. https://codereview.chromium.org/1874733002/
2. https://codereview.chromium.org/1869303004/

BUG=601788, 590358

[dshwang, 2016-04-11 11:38:57]

Description was changed from

==========
media: Implement zero-copy video playback for ffmpeg.

Current zero-copy video playback implementation is actually "one-copy video
playback".
The final VideoFrame is produced by following pipeline.
1. FFmpeg decoder produces a VideoFrame.
2. GpuMemoryBufferVideoFramePool copies the software VideoFrame to hardware
VideoFrame backed by GpuMemoryBuffer.
3. CC composites the mailbox belonging to hardware VideoFrame.

This CL gets rid of #2 step. FFmpegVideoDecoder will decode video frame
directly on hardware VideoFrame backed by GpuMemoryBuffer.

This CL supports only I420, YV12 and YV12A.

TODO: support more YUV planes.

BUG=601788, 590358
==========

to

==========
media: Implement zero-copy video playback for ffmpeg.

Current zero-copy video playback implementation is actually "one-copy video
playback".
The final VideoFrame is produced by following pipeline.
1. FFmpeg decoder produces a VideoFrame.
2. GpuMemoryBufferVideoFramePool copies the software VideoFrame to hardware
VideoFrame backed by GpuMemoryBuffer.
3. CC composites the mailbox belonging to hardware VideoFrame.

This CL gets rid of #2 step. FFmpegVideoDecoder will decode video frame
directly on hardware VideoFrame backed by GpuMemoryBuffer.

This CL supports only I420, YV12 and YV12A.

TODO: support more YUV planes.
Dependency: 
1. https://codereview.chromium.org/1874733002/
2. https://codereview.chromium.org/1869303004/

BUG=601788, 590358
==========

[dshwang, 2016-04-11 11:39:26]

dongseong.hwang@intel.com changed reviewers:
+ dalecurtis@chromium.org, dcastagna@chromium.org

[dshwang, 2016-04-11 11:42:23]

I extract ffmpeg change from https://codereview.chromium.org/1869303004/
It's because DaleCurtis	explained ffmpeg could read GMBs even after VideoFrame
is issued to compositor.

BTW, even if it's true, ChromeOS on Intel Core is fine, because last level cache
makes sure coherency between GPU and CPU without any lock.
So I think we can enable it on at least ChromeOS on Intel Core.

[dshwang, 2016-04-11 11:42:34]

dongseong.hwang@intel.com changed reviewers:
+ tiago.vignatti@intel.com