--- a/dom/media/MediaStreamGraph.cpp
+++ b/dom/media/MediaStreamGraph.cpp
@@ -174,22 +174,31 @@ MediaStreamGraphImpl::ExtractPendingInpu
         }
       }
     }
     finished = aStream->mUpdateFinished;
     bool notifiedTrackCreated = false;
     for (int32_t i = aStream->mUpdateTracks.Length() - 1; i >= 0; --i) {
       SourceMediaStream::TrackData* data = &aStream->mUpdateTracks[i];
       aStream->ApplyTrackDisabling(data->mID, data->mData);
+      StreamTime offset = (data->mCommands & SourceMediaStream::TRACK_CREATE)
+          ? data->mStart : aStream->mBuffer.FindTrack(data->mID)->GetSegment()->GetDuration();
       for (MediaStreamListener* l : aStream->mListeners) {
-        StreamTime offset = (data->mCommands & SourceMediaStream::TRACK_CREATE)
-            ? data->mStart : aStream->mBuffer.FindTrack(data->mID)->GetSegment()->GetDuration();
         l->NotifyQueuedTrackChanges(this, data->mID,
                                     offset, data->mCommands, *data->mData);
       }
+      for (TrackBound<MediaStreamTrackListener>& b : aStream->mTrackListeners) {
+        if (b.mTrackID != data->mID) {
+          continue;
+        }
+        b.mListener->NotifyQueuedChanges(this, offset, *data->mData);
+        if (data->mCommands & SourceMediaStream::TRACK_END) {
+          b.mListener->NotifyEnded();
+        }
+      }
       if (data->mCommands & SourceMediaStream::TRACK_CREATE) {
         MediaSegment* segment = data->mData.forget();
         STREAM_LOG(LogLevel::Debug, ("SourceMediaStream %p creating track %d, start %lld, initial end %lld",
                                   aStream, data->mID, int64_t(data->mStart),
                                   int64_t(segment->GetDuration())));
 
         data->mEndOfFlushedData += segment->GetDuration();
         aStream->mBuffer.AddTrack(data->mID, data->mStart, segment);
@@ -2222,16 +2231,77 @@ MediaStream::RemoveListener(MediaStreamL
   // If the stream is destroyed the Listeners have or will be
   // removed.
   if (!IsDestroyed()) {
     GraphImpl()->AppendMessage(MakeUnique<Message>(this, aListener));
   }
 }
 
 void
+MediaStream::AddTrackListenerImpl(already_AddRefed<MediaStreamTrackListener> aListener,
+                                  TrackID aTrackID)
+{
+  TrackBound<MediaStreamTrackListener>* l = mTrackListeners.AppendElement();
+  l->mListener = aListener;
+  l->mTrackID = aTrackID;
+}
+
+void
+MediaStream::AddTrackListener(MediaStreamTrackListener* aListener,
+                              TrackID aTrackID)
+{
+  class Message : public ControlMessage {
+  public:
+    Message(MediaStream* aStream, MediaStreamTrackListener* aListener,
+            TrackID aTrackID) :
+      ControlMessage(aStream), mListener(aListener), mTrackID(aTrackID) {}
+    virtual void Run()
+    {
+      mStream->AddTrackListenerImpl(mListener.forget(), mTrackID);
+    }
+    RefPtr<MediaStreamTrackListener> mListener;
+    TrackID mTrackID;
+  };
+  GraphImpl()->AppendMessage(MakeUnique<Message>(this, aListener, aTrackID));
+}
+
+void
+MediaStream::RemoveTrackListenerImpl(MediaStreamTrackListener* aListener,
+                                     TrackID aTrackID)
+{
+  for (size_t i = 0; i < mTrackListeners.Length(); ++i) {
+    if (mTrackListeners[i].mListener == aListener &&
+        mTrackListeners[i].mTrackID == aTrackID) {
+      mTrackListeners[i].mListener->NotifyRemoved();
+      mTrackListeners.RemoveElementAt(i);
+      return;
+    }
+  }
+}
+
+void
+MediaStream::RemoveTrackListener(MediaStreamTrackListener* aListener,
+                                 TrackID aTrackID)
+{
+  class Message : public ControlMessage {
+  public:
+    Message(MediaStream* aStream, MediaStreamTrackListener* aListener,
+            TrackID aTrackID) :
+      ControlMessage(aStream), mListener(aListener), mTrackID(aTrackID) {}
+    virtual void Run()
+    {
+      mStream->RemoveTrackListenerImpl(mListener, mTrackID);
+    }
+    RefPtr<MediaStreamTrackListener> mListener;
+    TrackID mTrackID;
+  };
+  GraphImpl()->AppendMessage(MakeUnique<Message>(this, aListener, aTrackID));
+}
+
+void
 MediaStream::RunAfterPendingUpdates(already_AddRefed<nsIRunnable> aRunnable)
 {
   MOZ_ASSERT(NS_IsMainThread());
   MediaStreamGraphImpl* graph = GraphImpl();
   nsCOMPtr<nsIRunnable> runnable(aRunnable);
 
   // Special case when a non-realtime graph has not started, to ensure the
   // runnable will run in finite time.

--- a/dom/media/MediaStreamGraph.h
+++ b/dom/media/MediaStreamGraph.h
@@ -212,16 +212,51 @@ protected:
   // Protected destructor, to discourage deletion outside of Release():
   virtual ~AudioDataListener() {}
 
 public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AudioDataListener)
 };
 
 /**
+ * This is a base class for media graph thread listener callbacks locked to
+ * specific tracks. Override methods to be notified of audio or video data or
+ * changes in track state.
+ *
+ * All notification methods are called from the media graph thread. Overriders
+ * of these methods are responsible for all synchronization. Beware!
+ * These methods are called without the media graph monitor held, so
+ * reentry into media graph methods is possible, although very much discouraged!
+ * You should do something non-blocking and non-reentrant (e.g. dispatch an
+ * event to some thread) and return.
+ * The listener is not allowed to add/remove any listeners from the parent
+ * stream.
+ *
+ * If a listener is attached to a track that has already ended, we guarantee
+ * to call NotifyEnded.
+ */
+class MediaStreamTrackListener
+{
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaStreamTrackListener)
+
+public:
+  virtual void NotifyQueuedChanges(MediaStreamGraph* aGraph,
+                                   StreamTime aTrackOffset,
+                                   const MediaSegment& aQueuedMedia) {}
+
+  virtual void NotifyEnded() {}
+
+  virtual void NotifyRemoved() {}
+
+protected:
+  virtual ~MediaStreamTrackListener() {}
+};
+
+
+/**
  * This is a base class for media graph thread listener direct callbacks
  * from within AppendToTrack().  Note that your regular listener will
  * still get NotifyQueuedTrackChanges() callbacks from the MSG thread, so
  * you must be careful to ignore them if AddDirectListener was successful.
  */
 class MediaStreamDirectListener : public MediaStreamListener
 {
 public:
@@ -274,16 +309,26 @@ class SourceMediaStream;
 class ProcessedMediaStream;
 class MediaInputPort;
 class AudioNodeEngine;
 class AudioNodeExternalInputStream;
 class AudioNodeStream;
 class CameraPreviewMediaStream;
 
 /**
+ * Helper struct for binding a track listener to a specific TrackID.
+ */
+template<typename Listener>
+struct TrackBound
+{
+  RefPtr<Listener> mListener;
+  TrackID mTrackID;
+};
+
+/**
  * A stream of synchronized audio and video data. All (not blocked) streams
  * progress at the same rate --- "real time". Streams cannot seek. The only
  * operation readers can perform on a stream is to read the next data.
  *
  * Consumers of a stream can be reading from it at different offsets, but that
  * should only happen due to the order in which consumers are being run.
  * Those offsets must not diverge in the long term, otherwise we would require
  * unbounded buffering.
@@ -395,16 +440,20 @@ public:
   // Suspend message reaches the graph, the stream stops processing. It
   // ignores its inputs and produces silence/no video until Resumed. Its
   // current time does not advance.
   virtual void Suspend();
   virtual void Resume();
   // Events will be dispatched by calling methods of aListener.
   virtual void AddListener(MediaStreamListener* aListener);
   virtual void RemoveListener(MediaStreamListener* aListener);
+  virtual void AddTrackListener(MediaStreamTrackListener* aListener,
+                                TrackID aTrackID);
+  virtual void RemoveTrackListener(MediaStreamTrackListener* aListener,
+                                   TrackID aTrackID);
   // A disabled track has video replaced by black, and audio replaced by
   // silence.
   void SetTrackEnabled(TrackID aTrackID, bool aEnabled);
 
   // Finish event will be notified by calling methods of aListener. It is the
   // responsibility of the caller to remove aListener before it is destroyed.
   void AddMainThreadListener(MainThreadMediaStreamListener* aListener);
   // It's safe to call this even if aListener is not currently a listener;
@@ -491,16 +540,20 @@ public:
     return !mAudioOutputs.IsEmpty();
   }
   void RemoveAudioOutputImpl(void* aKey);
   void AddVideoOutputImpl(already_AddRefed<VideoFrameContainer> aContainer);
   void RemoveVideoOutputImpl(VideoFrameContainer* aContainer);
   void AddListenerImpl(already_AddRefed<MediaStreamListener> aListener);
   void RemoveListenerImpl(MediaStreamListener* aListener);
   void RemoveAllListenersImpl();
+  virtual void AddTrackListenerImpl(already_AddRefed<MediaStreamTrackListener> aListener,
+                                    TrackID aTrackID);
+  virtual void RemoveTrackListenerImpl(MediaStreamTrackListener* aListener,
+                                       TrackID aTrackID);
   virtual void SetTrackEnabledImpl(TrackID aTrackID, bool aEnabled);
 
   void AddConsumer(MediaInputPort* aPort)
   {
     mConsumers.AppendElement(aPort);
   }
   void RemoveConsumer(MediaInputPort* aPort)
   {
@@ -644,16 +697,17 @@ protected:
     float mVolume;
   };
   nsTArray<AudioOutput> mAudioOutputs;
   nsTArray<RefPtr<VideoFrameContainer> > mVideoOutputs;
   // We record the last played video frame to avoid playing the frame again
   // with a different frame id.
   VideoFrame mLastPlayedVideoFrame;
   nsTArray<RefPtr<MediaStreamListener> > mListeners;
+  nsTArray<TrackBound<MediaStreamTrackListener>> mTrackListeners;
   nsTArray<MainThreadMediaStreamListener*> mMainThreadListeners;
   nsTArray<TrackID> mDisabledTrackIDs;
 
   // GraphTime at which this stream starts blocking.
   // This is only valid up to mStateComputedTime. The stream is considered to
   // have not been blocked before mCurrentTime (its mBufferStartTime is increased
   // as necessary to account for that time instead).
   GraphTime mStartBlocking;

--- a/dom/media/MediaStreamTrack.cpp
+++ b/dom/media/MediaStreamTrack.cpp
@@ -1,16 +1,17 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "MediaStreamTrack.h"
 
 #include "DOMMediaStream.h"
+#include "MediaStreamGraph.h"
 #include "nsIUUIDGenerator.h"
 #include "nsServiceManagerUtils.h"
 
 #ifdef LOG
 #undef LOG
 #endif
 
 static PRLogModuleInfo* gMediaStreamTrackLog;
@@ -192,10 +193,28 @@ MediaStreamTrack::GetInputStream()
 }
 
 ProcessedMediaStream*
 MediaStreamTrack::GetOwnedStream()
 {
   return GetStream()->GetOwnedStream();
 }
 
+void
+MediaStreamTrack::AddListener(MediaStreamTrackListener* aListener)
+{
+  LOG(LogLevel::Debug, ("MediaStreamTrack %p adding listener %p",
+                        this, aListener));
+
+  GetOwnedStream()->AddTrackListener(aListener, mTrackID);
+}
+
+void
+MediaStreamTrack::RemoveListener(MediaStreamTrackListener* aListener)
+{
+  LOG(LogLevel::Debug, ("MediaStreamTrack %p removing listener %p",
+                        this, aListener));
+
+  GetOwnedStream()->RemoveTrackListener(aListener, mTrackID);
+}
+
 } // namespace dom
 } // namespace mozilla

--- a/dom/media/MediaStreamTrack.h
+++ b/dom/media/MediaStreamTrack.h
@@ -14,16 +14,17 @@
 #include "PrincipalChangeObserver.h"
 
 namespace mozilla {
 
 class DOMMediaStream;
 class MediaEnginePhotoCallback;
 class MediaStream;
 class MediaStreamGraph;
+class MediaStreamTrackListener;
 class ProcessedMediaStream;
 
 namespace dom {
 
 class AudioStreamTrack;
 class VideoStreamTrack;
 
 /**
@@ -249,16 +250,28 @@ public:
 
   /**
    * Remove an added PrincipalChangeObserver from this track.
    *
    * Returns true if it was successfully removed.
    */
   bool RemovePrincipalChangeObserver(PrincipalChangeObserver<MediaStreamTrack>* aObserver);
 
+  /**
+   * Adds a MediaStreamTrackListener to the MediaStreamGraph representation of
+   * this track.
+   */
+  void AddListener(MediaStreamTrackListener* aListener);
+
+  /**
+   * Removes a MediaStreamTrackListener from the MediaStreamGraph representation
+   * of this track.
+   */
+  void RemoveListener(MediaStreamTrackListener* aListener);
+
 protected:
   virtual ~MediaStreamTrack();
 
   // Returns the original DOMMediaStream's underlying input stream.
   MediaStream* GetInputStream();
 
   // Returns the owning DOMMediaStream's underlying owned stream.
   ProcessedMediaStream* GetOwnedStream();

--- a/dom/media/TrackUnionStream.cpp
+++ b/dom/media/TrackUnionStream.cpp
@@ -234,16 +234,21 @@ TrackUnionStream::TrackUnionStream(DOMMe
       nsAutoPtr<MediaSegment> segment;
       segment = outputTrack->GetSegment()->CreateEmptyClone();
       l->NotifyQueuedTrackChanges(Graph(), outputTrack->GetID(), offset,
                                   MediaStreamListener::TRACK_EVENT_ENDED,
                                   *segment,
                                   mTrackMap[aIndex].mInputPort->GetSource(),
                                   mTrackMap[aIndex].mInputTrackID);
     }
+    for (TrackBound<MediaStreamTrackListener>& b : mTrackListeners) {
+      if (b.mTrackID == outputTrack->GetID()) {
+        b.mListener->NotifyEnded();
+      }
+    }
     outputTrack->SetEnded();
   }
 
   void TrackUnionStream::CopyTrackData(StreamBuffer::Track* aInputTrack,
                      uint32_t aMapIndex, GraphTime aFrom, GraphTime aTo,
                      bool* aOutputTrackFinished)
   {
     TrackMapEntry* map = &mTrackMap[aMapIndex];
@@ -295,12 +300,18 @@ TrackUnionStream::TrackUnionStream(DOMMe
         }
       }
       ApplyTrackDisabling(outputTrack->GetID(), segment);
       for (uint32_t j = 0; j < mListeners.Length(); ++j) {
         MediaStreamListener* l = mListeners[j];
         l->NotifyQueuedTrackChanges(Graph(), outputTrack->GetID(),
                                     outputStart, 0, *segment);
       }
+      for (TrackBound<MediaStreamTrackListener>& b : mTrackListeners) {
+        if (b.mTrackID != outputTrack->GetID()) {
+          continue;
+        }
+        b.mListener->NotifyQueuedChanges(Graph(), outputStart, *segment);
+      }
       outputTrack->GetSegment()->AppendFrom(segment);
     }
   }
 } // namespace mozilla