Bug 1913624 - Remove expired telemetry histogram MEDIA_MKV_CANPLAY_REQUESTED, r=TravisLong.

Differential Revision: https://phabricator.services.mozilla.com/D219480

dom/media/DecoderTraits.cpp

@@ -48,14 +48,6 @@ bool DecoderTraits::IsHttpLiveStreamingType(const MediaContainerType& aType) {
       mimeType == MEDIAMIMETYPE("audio/x-mpegurl");
 }
 
-/* static */
-bool DecoderTraits::IsMatroskaType(const MediaContainerType& aType) {
-  const auto& mimeType = aType.Type();
-  // https://matroska.org/technical/specs/notes.html
-  return mimeType == MEDIAMIMETYPE("audio/x-matroska") ||
-         mimeType == MEDIAMIMETYPE("video/x-matroska");
-}
-
 static CanPlayStatus CanHandleCodecsType(
     const MediaContainerType& aType, DecoderDoctorDiagnostics* aDiagnostics) {
   // We should have been given a codecs string, though it may be empty.
@@ -137,10 +129,6 @@ static CanPlayStatus CanHandleMediaType(
   }
 #endif
 
-  if (DecoderTraits::IsMatroskaType(aType)) {
-    Telemetry::Accumulate(Telemetry::MEDIA_MKV_CANPLAY_REQUESTED, true);
-  }
-
   if (aType.ExtendedType().HaveCodecs()) {
     CanPlayStatus result = CanHandleCodecsType(aType, aDiagnostics);
     if (result == CANPLAY_NO || result == CANPLAY_YES) {

dom/media/DecoderTraits.h

@@ -55,9 +55,6 @@ class DecoderTraits {
   // Returns true if aType is MIME type of hls.
   static bool IsHttpLiveStreamingType(const MediaContainerType& aType);
 
-  // Returns true if aType is matroska type.
-  static bool IsMatroskaType(const MediaContainerType& aType);
-
   // Returns an array of all TrackInfo objects described by this type.
   static nsTArray<UniquePtr<TrackInfo>> GetTracksInfo(
       const MediaContainerType& aType);

toolkit/components/telemetry/Histograms.json

@@ -10134,15 +10134,6 @@
     "bug_numbers": [1767334, 1768033],
     "description": "Whether H264 encoding is an available capability for being sent to the content processes. 0=no h264, 1=h264 avaiable, 2=no h264 1 directory added, 3=no h264 >1 directories added, 4=directory adds in prorgress"
   },
-  "MEDIA_MKV_CANPLAY_REQUESTED": {
-    "record_in_processes": ["content"],
-    "products": ["firefox"],
-    "alert_emails": ["media-alerts@mozilla.com"],
-    "expires_in_version": "118",
-    "kind": "boolean",
-    "description": "Reports a true value when a page requests canPlayType for a matroska media type.",
-    "bug_numbers": [1429986, 1570634, 1606206, 1689266, 1754643, 1813150]
-  },
   "MEDIA_MP4_PARSE_SAMPLE_DESCRIPTION_ENTRIES_HAVE_MULTIPLE_CODECS": {
     "record_in_processes": ["main", "content"],
     "products": ["firefox", "fennec"],