--- a/dom/media/MediaDecoderReader.h
+++ b/dom/media/MediaDecoderReader.h
@@ -6,16 +6,17 @@
 #if !defined(MediaDecoderReader_h_)
 #define MediaDecoderReader_h_
 
 #include "mozilla/MozPromise.h"
 
 #include "AbstractMediaDecoder.h"
 #include "MediaInfo.h"
 #include "MediaData.h"
+#include "MediaMetadataManager.h"
 #include "MediaQueue.h"
 #include "MediaTimer.h"
 #include "AudioCompactor.h"
 #include "Intervals.h"
 #include "TimeUnits.h"
 
 namespace mozilla {
 
@@ -322,16 +323,20 @@ public:
   virtual bool IsAsync() const { return false; }
 
   // Returns true if this decoder reader uses hardware accelerated video
   // decoding.
   virtual bool VideoIsHardwareAccelerated() const { return false; }
 
   virtual void DisableHardwareAcceleration() {}
 
+  TimedMetadataEventSource& TimedMetadataEvent() {
+    return mTimedMetadataEvent;
+  }
+
 protected:
   virtual ~MediaDecoderReader();
 
   // Overrides of this function should decodes an unspecified amount of
   // audio data, enqueuing the audio data in mAudioQueue. Returns true
   // when there's more audio to decode, false if the audio is finished,
   // end of file has been reached, or an un-recoverable read error has
   // occured. This function blocks until the decode is complete.
@@ -413,16 +418,19 @@ protected:
 
   // This is a quick-and-dirty way for DecodeAudioData implementations to
   // communicate the presence of a decoding error to RequestAudioData. We should
   // replace this with a promise-y mechanism as we make this stuff properly
   // async.
   bool mHitAudioDecodeError;
   bool mShutdown;
 
+  // Used to send TimedMetadata to the listener.
+  TimedMetadataEventProducer mTimedMetadataEvent;
+
 private:
   // Promises used only for the base-class (sync->async adapter) implementation
   // of Request{Audio,Video}Data.
   MozPromiseHolder<AudioDataPromise> mBaseAudioPromise;
   MozPromiseHolder<VideoDataPromise> mBaseVideoPromise;
 
   bool mTaskQueueIsBorrowed;
 

--- a/dom/media/ogg/OggReader.cpp
+++ b/dom/media/ogg/OggReader.cpp
@@ -809,20 +809,21 @@ bool OggReader::ReadOggChain()
 
     chained = true;
     tags = newOpusState->GetTags();
   }
 
   if (chained) {
     SetChained(true);
     {
-      nsAutoPtr<MediaInfo> info(new MediaInfo(mInfo));
-      ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
       auto t = mDecodedAudioFrames * USECS_PER_S / mInfo.mAudio.mRate;
-      mDecoder->QueueMetadata(media::TimeUnit::FromMicroseconds(t), info, tags);
+      mTimedMetadataEvent.Notify(
+        TimedMetadata(media::TimeUnit::FromMicroseconds(t),
+                      Move(tags),
+                      nsAutoPtr<MediaInfo>(new MediaInfo(mInfo))));
     }
     return true;
   }
 
   return false;
 }
 
 nsresult OggReader::DecodeTheora(ogg_packet* aPacket, int64_t aTimeThreshold)