Use FFmpegVideoDecoder from a UtilityProcess

media/base/video_frame_pool.h

Index: media/base/video_frame_pool.h
diff --git a/media/base/video_frame_pool.h b/media/base/video_frame_pool.h
index ebd0e249af2e7a9d4f792c4ccb23657c7b5a214c..1a9855d3a787b7a9c69214166e7a1cfba53b1ed4 100644
--- a/media/base/video_frame_pool.h
+++ b/media/base/video_frame_pool.h
@@ -13,6 +13,20 @@
 
 namespace media {
 
+class VideoFramePoolDelegate {

[sandersd (OOO until July 31), 2016/12/15 00:38:01]

I am opposed to the name Delegate on the grounds that media/ has a few of them
and it never means the same thing. This particular usage might be better named
VideoFrameProvider? (Or go all the way and call it
VideoFrame::Provider/VideoFrame::Factory or something like that.)

+ public:
+  virtual ~VideoFramePoolDelegate() {}
+  virtual scoped_refptr<VideoFrame> CreateZeroInitializedFrame(
+      VideoPixelFormat format,
+      const gfx::Size& coded_size,
+      const gfx::Rect& visible_rect,
+      const gfx::Size& natural_size,
+      base::TimeDelta timestamp) = 0;
+
+  virtual scoped_refptr<VideoFrame> WrapVideoFrame(
+      const scoped_refptr<VideoFrame>& frame) = 0;
+};
+
 // Simple VideoFrame pool used to avoid unnecessarily allocating and destroying
 // VideoFrame objects. The pool manages the memory for the VideoFrame
 // returned by CreateFrame(). When one of these VideoFrames is destroyed,
@@ -37,7 +51,9 @@ class MEDIA_EXPORT VideoFramePool {
                                         const gfx::Size& natural_size,
                                         base::TimeDelta timestamp);
 
-protected:
+  void SetDelegate(std::unique_ptr<VideoFramePoolDelegate> delegate);

[sandersd (OOO until July 31), 2016/12/15 00:38:01]

It seems like the pool doesn't work without calling this. I recommend making it
a constructor argument with a default value.

+
+ protected:
   friend class VideoFramePoolTest;
 
   // Returns the number of frames in the pool for testing purposes.
@@ -46,6 +62,7 @@ protected:
  private:
   class PoolImpl;
   scoped_refptr<PoolImpl> pool_;
+  std::unique_ptr<VideoFramePoolDelegate> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoFramePool);
 };