Reland: Change the video color space default.

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 94091f875000285ef20e0e4767da8d3b1dbca46e..3ab99a90d734182fd0230a75f992c6580bcf4758 100644
--- a/media/ffmpeg/ffmpeg_common.h
+++ b/media/ffmpeg/ffmpeg_common.h
@@ -124,6 +124,8 @@ PixelFormatToVideoPixelFormat(PixelFormat pixel_format);
 // Converts video formats to its corresponding FFmpeg's pixel formats.
 PixelFormat VideoPixelFormatToPixelFormat(VideoPixelFormat video_format);
 
+ColorSpace AVColorSpaceToColorSpace(AVColorSpace color_space);
+
 // Convert FFmpeg UTC representation (YYYY-MM-DD HH:MM:SS) to base::Time.
 // Returns true and sets |*out| if |date_utc| contains a valid
 // date string. Otherwise returns fals and timeline_offset is unmodified.