media: Implement zero-copy video playback for ffmpeg.

media/renderers/default_renderer_factory.cc

Index: media/renderers/default_renderer_factory.cc
diff --git a/media/renderers/default_renderer_factory.cc b/media/renderers/default_renderer_factory.cc
index d50bd1171481a1a986052012f3301ba2c7ef9646..db909137602085a022f9689bdf6b12bf969a3cbc 100644
--- a/media/renderers/default_renderer_factory.cc
+++ b/media/renderers/default_renderer_factory.cc
@@ -87,8 +87,8 @@ ScopedVector<VideoDecoder> DefaultRendererFactory::CreateVideoDecoders(
     video_decoders.push_back(
         new GpuVideoDecoder(gpu_factories, request_surface_cb));
 
-#if !defined(MEDIA_DISABLE_LIBVPX)
   std::unique_ptr<GpuMemoryBufferVideoFramePool> gpu_video_frame_pool;
+#if !defined(MEDIA_DISABLE_LIBVPX)
   if (gpu_factories &&
       gpu_factories->ShouldUseGpuMemoryBuffersForVideoFrames()) {
     gpu_video_frame_pool.reset(
@@ -99,7 +99,13 @@ ScopedVector<VideoDecoder> DefaultRendererFactory::CreateVideoDecoders(
 #endif
 
 #if !defined(MEDIA_DISABLE_FFMPEG) && !defined(DISABLE_FFMPEG_VIDEO_DECODERS)
-  video_decoders.push_back(new FFmpegVideoDecoder());
+  if (gpu_factories &&
+      gpu_factories->ShouldUseGpuMemoryBuffersForVideoFrames()) {
+    gpu_video_frame_pool.reset(
+        new GpuMemoryBufferVideoFramePool(media_task_runner, gpu_factories));
+  }
+  video_decoders.push_back(
+      new FFmpegVideoDecoder(std::move(gpu_video_frame_pool)));
 #endif
 
   return video_decoders;