Add SourceBuffer implementations of Audio/VideoTracks

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

Index: third_party/WebKit/Source/modules/mediasource/SourceBuffer.h
diff --git a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.h b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.h
index a134238101c151fd740a7e3741209a1f19f1ccb8..56f440dd4f305b09654545c657e700c84212d6c5 100644
--- a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.h
+++ b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.h
@@ -43,6 +43,7 @@
 
 namespace blink {
 
+class AudioTrackList;
 class DOMArrayBuffer;
 class DOMArrayBufferView;
 class ExceptionState;
@@ -52,6 +53,7 @@ class MediaSource;
 class Stream;
 class TimeRanges;
 class TrackBase;
+class VideoTrackList;
 class WebSourceBuffer;
 
 class SourceBuffer final
@@ -89,6 +91,9 @@ public:
     TrackDefaultList* trackDefaults() const { return m_trackDefaults.get(); }
     void setTrackDefaults(TrackDefaultList*, ExceptionState&);
 
+    AudioTrackList& audioTracks();
+    VideoTrackList& videoTracks();
+
     void abortIfUpdating();
     void removedFromMediaSource();
 
@@ -148,6 +153,8 @@ private:
 
     HeapVector<WebMediaPlayer::TrackId> m_audioTrackIds;
     HeapVector<WebMediaPlayer::TrackId> m_videoTrackIds;
+    Member<AudioTrackList> m_audioTracks;
+    Member<VideoTrackList> m_videoTracks;
 
     AtomicString m_mode;
     bool m_updating;