media/filters: Relax the vp9 colorspace matching restriction

For the Intra only frames in profile0, we assign the default
color_space :BT_601 as per the spec. But there are lazily encoded
streams with UNKNOWN color space information in non-intra-only frames
and that will cause enum comparison mismatch for the current frame header
with the frame in the reference list. So we relax the requirement
a bit to cover more streams similar to the other media stacks like
libvpx, gstreamer etc

BUG=889768
R=dalecurtis@chromium.org, hiroh@chromium.org

Change-Id: I5c343d03a941a3aa1447d4f0d3cd4979b92c4adb
Reviewed-on: https://chromium-review.googlesource.com/c/1342776Reviewed-by: Fredrik Hubinette <hubbe@chromium.org>
Commit-Queue: Fredrik Hubinette <hubbe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609929}

media/filters/vp9_uncompressed_header_parser.cc

@@ -1028,7 +1028,15 @@ bool Vp9UncompressedHeaderParser::Parse(const uint8_t* stream,
             DVLOG(1) << "bit_depth of referenced frame mismatch";
             return false;
           }
-          if (fhdr->color_space != ref.color_space) {
+          // There are encoded streams with no color_space information
+          // with in the frame header of an Intra only frame, so we assigned the
+          // default color_space :BT_601 as per the spec. But reference list
+          // might have frames with UNKNOWN color space information too. So we
+          // relax the requirement a bit to cover more video samples and added
+          // an exception for UNKNOWN colorspace
+          if (fhdr->color_space != ref.color_space &&
+              fhdr->color_space != Vp9ColorSpace::UNKNOWN &&
+              ref.color_space != Vp9ColorSpace::UNKNOWN) {
             DVLOG(1) << "color_space of referenced frame mismatch";
             return false;
           }