Merge "The .mkv parser lib leaves some tracks NULL if it doesn't support them." into honeycomb

    for (size_t index = 0; index < tracks->GetTracksCount(); ++index) {

        const mkvparser::Track *track = tracks->GetTrackByIndex(index);

        if (track == NULL) {

            // Apparently this is currently valid (if unexpected) behaviour

            // of the mkv parser lib.

            continue;

        }

        const char *const codecID = track->GetCodecId();

        LOGV("codec id = %s", codecID);

        LOGV("codec name = %s", track->GetCodecNameAsUTF8());