Bug 1267637: P2. Ignore outright audio track considered invalid. r=gerald

MozReview-Commit-ID: 6rMz8cjgLiY

--HG--
extra : rebase_source : 9e006f0125d9d3c786d64aae5f521f8239bbae8b

dom/media/MediaFormatReader.cpp

@@ -303,14 +303,21 @@ MediaFormatReader::OnDemuxerInitDone(nsresult)
       mMetadataPromise.Reject(ReadMetadataFailureReason::METADATA_ERROR, __func__);
       return;
     }
-    mInfo.mAudio = *mAudio.mTrackDemuxer->GetInfo()->GetAsAudioInfo();
-    UniquePtr<TrackInfo> info(mAudio.mTrackDemuxer->GetInfo());
-    for (const MetadataTag& tag : info->mTags) {
+    UniquePtr<TrackInfo> audioInfo = mAudio.mTrackDemuxer->GetInfo();
+    // We actively ignore audio tracks that we know we can't play.
+    audioActive = audioInfo && audioInfo->IsValid();
+    if (audioActive) {
+      mInfo.mAudio = *audioInfo->GetAsAudioInfo();
+      for (const MetadataTag& tag : audioInfo->mTags) {
         tags->Put(tag.mKey, tag.mValue);
       }
       mAudio.mCallback = new DecoderCallback(this, TrackInfo::kAudioTrack);
       mAudio.mTimeRanges = mAudio.mTrackDemuxer->GetBuffered();
       mTrackDemuxersMayBlock |= mAudio.mTrackDemuxer->GetSamplesMayBlock();
+    } else {
+      mAudio.mTrackDemuxer->BreakCycles();
+      mAudio.mTrackDemuxer = nullptr;
+    }
   }
 
   UniquePtr<EncryptionInfo> crypto = mDemuxer->GetCrypto();