Fix support for yuv_422 pixel format.

media/ffmpeg/ffmpeg_common.h

Index: media/ffmpeg/ffmpeg_common.h
diff --git a/media/ffmpeg/ffmpeg_common.h b/media/ffmpeg/ffmpeg_common.h
index dbdbc6e3923ae29366928265cafdd65dda09f3b2..16aeec91933b12322e81733d3da0b8905bf7f3c1 100644
--- a/media/ffmpeg/ffmpeg_common.h
+++ b/media/ffmpeg/ffmpeg_common.h
@@ -82,6 +82,12 @@ CodecID VideoCodecToCodecID(VideoCodec video_codec);
 ChannelLayout ChannelLayoutToChromeChannelLayout(int64_t layout,
                                                  int channels);
 
+// Converts FFmpeg's pixel formats to its corresponding supported video format.
+VideoFrame::Format PixelFormatToVideoFormat(PixelFormat pixel_format);
+
+// Converts video formats to its corresponding FFmpeg's pixel formats.
+PixelFormat VideoFormatToPixelFormat(VideoFrame::Format video_format);
+
 // Calculates duration of one frame in the |stream| based on its frame rate.
 base::TimeDelta GetFrameDuration(AVStream* stream);