Add support for Rec709 color space videos in software YUV convert path.

media/filters/ffmpeg_video_decoder.cc

Index: media/filters/ffmpeg_video_decoder.cc
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index 93dcee2157a4bfc12f25759eb55dc6abc4431607..7a8c80f2df965be2b1f0e654aa56c655efd441c4 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -86,10 +86,16 @@ int FFmpegVideoDecoder::GetVideoBuffer(struct AVCodecContext* codec_context,
   // updated width/height/pix_fmt, which can change for adaptive
   // content.
   VideoFrame::Format format = PixelFormatToVideoFormat(codec_context->pix_fmt);
+  if (format == VideoFrame::YV12 &&
+      codec_context->colorspace == AVCOL_SPC_BT709) {
+    format = VideoFrame::YV12HD;
+  }
+
   if (format == VideoFrame::UNKNOWN)
     return AVERROR(EINVAL);
   DCHECK(format == VideoFrame::YV12 || format == VideoFrame::YV16 ||
-         format == VideoFrame::YV12J || format == VideoFrame::YV24);
+         format == VideoFrame::YV12J || format == VideoFrame::YV24 ||
+         format == VideoFrame::YV12HD);
 
   gfx::Size size(codec_context->width, codec_context->height);
   const int ret = av_image_check_size(size.width(), size.height(), 0, NULL);