Revert of Change the video color space default.

media/formats/mp4/mp4_stream_parser.cc

Index: media/formats/mp4/mp4_stream_parser.cc
diff --git a/media/formats/mp4/mp4_stream_parser.cc b/media/formats/mp4/mp4_stream_parser.cc
index d8a6980b7faefc1eb0ff202e7c57c418f988c36e..333f43e8f81c76a794acea06375f1c6fee9745fe 100644
--- a/media/formats/mp4/mp4_stream_parser.cc
+++ b/media/formats/mp4/mp4_stream_parser.cc
@@ -293,8 +293,8 @@
       is_video_track_encrypted_ = entry.sinf.info.track_encryption.is_encrypted;
       DVLOG(1) << "is_video_track_encrypted_: " << is_video_track_encrypted_;
       video_config.Initialize(kCodecH264, H264PROFILE_MAIN, VideoFrame::YV12,
-                              VideoFrame::COLOR_SPACE_HD_REC709,
-                              coded_size, visible_rect, natural_size,
+                              VideoFrame::COLOR_SPACE_UNSPECIFIED, coded_size,
+                              visible_rect, natural_size,
                               // No decoder-specific buffer needed for AVC;
                               // SPS/PPS are embedded in the video stream
                               NULL, 0, is_video_track_encrypted_, false);