MSE: Enable 'video/mp4' opus IsTypeSupported success

Previously, only 'audio/mp4' would report support for opus codec in
Chromium MSE. This change adds support for opus codec in 'video/mp4'
mime to Chromium. For example, MediaSource.IsTypeSupported('video/mp4;
codecs="opus"') now returns true with this change.

Also adds a couple opus-in-mp4 and -in-webm IsTypeSupported test cases
to the interop wpt suite, though the particular test file is currently
marked [ failure pass ] in Blink TestExpectations due to those tests
containing a mix of proprietary and non-proprietary codecs such that
bots running without all the necessary codec support will fail the test.
I've filed https://crbug.com/961443 to track improving MSE
IsTypeSupported test coverage at least in Chromium.

BUG=649438

Change-Id: I7c47b6c2566432be9627394f5ff30e0a43888300
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1603527Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Matthew Wolenetz <wolenetz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658339}

media/filters/stream_parser_factory.cc

@@ -230,6 +230,7 @@ static const CodecInfo kMPEG4FLACCodecInfo = {"flac", CodecInfo::AUDIO, nullptr,
                                               CodecInfo::HISTOGRAM_FLAC};
 
 static const CodecInfo* const kVideoMP4Codecs[] = {&kMPEG4FLACCodecInfo,
+                                                   &kOpusCodecInfo,
                                                    &kMPEG4VP09CodecInfo,
 #if BUILDFLAG(USE_PROPRIETARY_CODECS)
                                                    &kH264AVC1CodecInfo,

third_party/blink/web_tests/external/wpt/media-source/mediasource-is-type-supported.html

@@ -66,6 +66,8 @@
               'video/webm;codecs="vorbis, vp8"',
               'audio/webm;codecs="vorbis"',
               'AUDIO/WEBM;CODECS="vorbis"',
+              'audio/webm;codecs="opus"',
+              'video/webm;codecs="opus"'
           ], true, 'Test valid WebM type');
 
           test_type_support([
@@ -78,6 +80,8 @@
               'video/mp4;codecs="avc1.4d001e,mp4a.40.2"',
               'video/mp4;codecs="mp4a.40.2 , avc1.4d001e "',
               'video/mp4;codecs="avc1.4d001e,mp4a.40.5"',
+              'audio/mp4;codecs="opus"',
+              'video/mp4;codecs="opus"'
           ], true, 'Test valid MP4 type');
         </script>
     </body>