Generate and assign media track ids in demuxers.

third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp

Index: third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
diff --git a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
index ea97613aa50607a193833f1304a868f28a7b82ad..4c8bec3f5f5c0d10e9bbdd614994800ce72e9d5e 100644
--- a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
+++ b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
@@ -590,8 +590,10 @@ WebVector<WebMediaPlayer::TrackId> SourceBuffer::initializationSegmentReceived(c
     unsigned resultIdx = 0;
     for (const auto& trackInfo : newTracks) {
         if (!RuntimeEnabledFeatures::audioVideoTracksEnabled()) {
-            static WebMediaPlayer::TrackId nextTrackId = 0;
-            result[resultIdx++] = ++nextTrackId;
+            static unsigned nextTrackId = 0;
+            StringBuilder stringBuilder;
+            stringBuilder.appendNumber(++nextTrackId);
+            result[resultIdx++] = stringBuilder.toString();
             continue;
         }
 
@@ -599,12 +601,12 @@ WebVector<WebMediaPlayer::TrackId> SourceBuffer::initializationSegmentReceived(c
         if (trackInfo.trackType == WebMediaPlayer::AudioTrack) {
             AudioTrack* audioTrack = nullptr;
             if (!m_firstInitializationSegmentReceived) {
-                audioTrack = AudioTrack::create(trackInfo.byteStreamTrackId, trackInfo.kind, trackInfo.label, trackInfo.language, false);
+                audioTrack = AudioTrack::create(trackInfo.id, trackInfo.kind, trackInfo.label, trackInfo.language, false);
                 SourceBufferTrackBaseSupplement::setSourceBuffer(*audioTrack, this);
                 audioTracks().add(audioTrack);
                 m_source->mediaElement()->audioTracks().add(audioTrack);
             } else {
-                audioTrack = findExistingTrackById(audioTracks(), trackInfo.byteStreamTrackId);
+                audioTrack = findExistingTrackById(audioTracks(), trackInfo.id);
                 DCHECK(audioTrack);
             }
             trackBase = audioTrack;
@@ -612,12 +614,12 @@ WebVector<WebMediaPlayer::TrackId> SourceBuffer::initializationSegmentReceived(c
         } else if (trackInfo.trackType == WebMediaPlayer::VideoTrack) {
             VideoTrack* videoTrack = nullptr;
             if (!m_firstInitializationSegmentReceived) {
-                videoTrack = VideoTrack::create(trackInfo.byteStreamTrackId, trackInfo.kind, trackInfo.label, trackInfo.language, false);
+                videoTrack = VideoTrack::create(trackInfo.id, trackInfo.kind, trackInfo.label, trackInfo.language, false);
                 SourceBufferTrackBaseSupplement::setSourceBuffer(*videoTrack, this);
                 videoTracks().add(videoTrack);
                 m_source->mediaElement()->videoTracks().add(videoTrack);
             } else {
-                videoTrack = findExistingTrackById(videoTracks(), trackInfo.byteStreamTrackId);
+                videoTrack = findExistingTrackById(videoTracks(), trackInfo.id);
                 DCHECK(videoTrack);
             }
             trackBase = videoTrack;
@@ -630,8 +632,8 @@ WebVector<WebMediaPlayer::TrackId> SourceBuffer::initializationSegmentReceived(c
         const char* logActionStr = m_firstInitializationSegmentReceived ? "using existing" : "added";
         const char* logTrackTypeStr = (trackInfo.trackType == WebMediaPlayer::AudioTrack) ? "audio" : "video";
         DVLOG(SOURCE_BUFFER_LOG_LEVEL) << __FUNCTION__ << "(" << this << ") " << logActionStr << " "
-            << logTrackTypeStr << " Track " << trackBase << "trackId=" << trackBase->trackId() << " id="
-            << trackBase->id() << " label=" << trackBase->label() << " lang=" << trackBase->language();
+            << logTrackTypeStr << " Track " << trackBase << " trackId=" << (String)trackBase->trackId()
+            << " label=" << trackBase->label() << " lang=" << trackBase->language();
 #endif
     }