diff --git a/dom/media/MediaDecoderReader.h b/dom/media/MediaDecoderReader.h
index 7c64bd44b4d2..032382a02093 100644
--- a/dom/media/MediaDecoderReader.h
+++ b/dom/media/MediaDecoderReader.h
@@ -165,9 +165,6 @@ public:
   // upon calls to Request{Audio,Video}Data.
   virtual void SetDemuxOnly(bool /*aDemuxedOnly*/) {}
 
-  virtual bool HasAudio() = 0;
-  virtual bool HasVideo() = 0;
-
   // The default implementation of AsyncReadMetadata is implemented in terms of
   // synchronous ReadMetadata() calls. Implementations may also
   // override AsyncReadMetadata to create a more proper async implementation.
@@ -255,21 +252,9 @@ public:
     UpdateBuffered();
   }
 
-  // Notify the reader that data from the resource was evicted
-  // (MediaSource only).
-  virtual void NotifyDataRemoved() {}
-
   virtual MediaQueue<AudioData>& AudioQueue() { return mAudioQueue; }
   virtual MediaQueue<VideoData>& VideoQueue() { return mVideoQueue; }
 
-  // Returns a pointer to the decoder.
-  AbstractMediaDecoder* GetDecoder()
-  {
-    return mDecoder;
-  }
-
-  MediaInfo GetMediaInfo() { return mInfo; }
-
   AbstractCanonical<media::TimeIntervals>* CanonicalBuffered()
   {
     return &mBuffered;
diff --git a/dom/media/MediaFormatReader.cpp b/dom/media/MediaFormatReader.cpp
index 13f4a1acc1bd..89f79fdbfe41 100644
--- a/dom/media/MediaFormatReader.cpp
+++ b/dom/media/MediaFormatReader.cpp
@@ -1544,11 +1544,8 @@ MediaFormatReader::NotifyDemuxer(uint32_t aLength, int64_t aOffset)
     return;
   }
 
-  if (aLength || aOffset) {
-    mDemuxer->NotifyDataArrived();
-  } else {
-    mDemuxer->NotifyDataRemoved();
-  }
+  mDemuxer->NotifyDataArrived();
+
   if (!mInitDone) {
     return;
   }
@@ -1571,14 +1568,6 @@ MediaFormatReader::NotifyDataArrivedInternal(uint32_t aLength, int64_t aOffset)
   NotifyDemuxer(aLength, aOffset);
 }
 
-void
-MediaFormatReader::NotifyDataRemoved()
-{
-  MOZ_ASSERT(OnTaskQueue());
-
-  NotifyDemuxer(0, 0);
-}
-
 bool
 MediaFormatReader::ForceZeroStartTime() const
 {
diff --git a/dom/media/MediaFormatReader.h b/dom/media/MediaFormatReader.h
index 6b71edc1565d..f14552ceca4c 100644
--- a/dom/media/MediaFormatReader.h
+++ b/dom/media/MediaFormatReader.h
@@ -42,16 +42,6 @@ public:
 
   RefPtr<AudioDataPromise> RequestAudioData() override;
 
-  bool HasVideo() override
-  {
-    return mVideo.mTrackDemuxer;
-  }
-
-  bool HasAudio() override
-  {
-    return mAudio.mTrackDemuxer;
-  }
-
   RefPtr<MetadataPromise> AsyncReadMetadata() override;
 
   void ReadUpdatedMetadata(MediaInfo* aInfo) override;
@@ -66,9 +56,8 @@ public:
 
 protected:
   void NotifyDataArrivedInternal(uint32_t aLength, int64_t aOffset) override;
-public:
-  void NotifyDataRemoved() override;
 
+public:
   media::TimeIntervals GetBuffered() override;
 
   virtual bool ForceZeroStartTime() const override;
@@ -113,6 +102,9 @@ public:
 #endif
 
 private:
+  bool HasVideo() { return mVideo.mTrackDemuxer; }
+  bool HasAudio() { return mAudio.mTrackDemuxer; }
+
   bool IsWaitingOnCDMResource();
 
   bool InitDemuxer();
diff --git a/dom/media/android/AndroidMediaReader.h b/dom/media/android/AndroidMediaReader.h
index 9f1888181be5..9e43b817e215 100644
--- a/dom/media/android/AndroidMediaReader.h
+++ b/dom/media/android/AndroidMediaReader.h
@@ -48,16 +48,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                 int64_t aTimeThreshold);
 
-  virtual bool HasAudio()
-  {
-    return mHasAudio;
-  }
-
-  virtual bool HasVideo()
-  {
-    return mHasVideo;
-  }
-
   virtual bool IsMediaSeekable()
   {
     // not used
diff --git a/dom/media/apple/AppleMP3Reader.cpp b/dom/media/apple/AppleMP3Reader.cpp
index 6480248bdf61..c5c7a6b006da 100644
--- a/dom/media/apple/AppleMP3Reader.cpp
+++ b/dom/media/apple/AppleMP3Reader.cpp
@@ -303,21 +303,6 @@ AppleMP3Reader::DecodeVideoFrame(bool &aKeyframeSkip,
   return false;
 }
 
-
-bool
-AppleMP3Reader::HasAudio()
-{
-  MOZ_ASSERT(OnTaskQueue());
-  return mStreamReady;
-}
-
-bool
-AppleMP3Reader::HasVideo()
-{
-  MOZ_ASSERT(OnTaskQueue());
-  return false;
-}
-
 bool
 AppleMP3Reader::IsMediaSeekable()
 {
diff --git a/dom/media/apple/AppleMP3Reader.h b/dom/media/apple/AppleMP3Reader.h
index dffa6bf5d500..f718a02528cb 100644
--- a/dom/media/apple/AppleMP3Reader.h
+++ b/dom/media/apple/AppleMP3Reader.h
@@ -28,9 +28,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                 int64_t aTimeThreshold) override;
 
-  virtual bool HasAudio() override;
-  virtual bool HasVideo() override;
-
   virtual nsresult ReadMetadata(MediaInfo* aInfo,
                                 MetadataTags** aTags) override;
 
diff --git a/dom/media/directshow/DirectShowReader.cpp b/dom/media/directshow/DirectShowReader.cpp
index a475ff03b4ea..7d493b0a079c 100644
--- a/dom/media/directshow/DirectShowReader.cpp
+++ b/dom/media/directshow/DirectShowReader.cpp
@@ -341,20 +341,6 @@ DirectShowReader::DecodeVideoFrame(bool &aKeyframeSkip,
   return false;
 }
 
-bool
-DirectShowReader::HasAudio()
-{
-  MOZ_ASSERT(OnTaskQueue());
-  return true;
-}
-
-bool
-DirectShowReader::HasVideo()
-{
-  MOZ_ASSERT(OnTaskQueue());
-  return false;
-}
-
 RefPtr<MediaDecoderReader::SeekPromise>
 DirectShowReader::Seek(int64_t aTargetUs, int64_t aEndTime)
 {
diff --git a/dom/media/directshow/DirectShowReader.h b/dom/media/directshow/DirectShowReader.h
index 8d80125ed23b..31ca2f64bc0e 100644
--- a/dom/media/directshow/DirectShowReader.h
+++ b/dom/media/directshow/DirectShowReader.h
@@ -47,9 +47,6 @@ public:
   bool DecodeVideoFrame(bool &aKeyframeSkip,
                         int64_t aTimeThreshold) override;
 
-  bool HasAudio() override;
-  bool HasVideo() override;
-
   nsresult ReadMetadata(MediaInfo* aInfo,
                         MetadataTags** aTags) override;
 
diff --git a/dom/media/gstreamer/GStreamerReader.h b/dom/media/gstreamer/GStreamerReader.h
index 6210af6cf38e..e34028e274e6 100644
--- a/dom/media/gstreamer/GStreamerReader.h
+++ b/dom/media/gstreamer/GStreamerReader.h
@@ -56,21 +56,13 @@ protected:
   virtual void NotifyDataArrivedInternal(uint32_t aLength,
                                          int64_t aOffset) override;
 public:
-
-  virtual bool HasAudio() override {
-    return mInfo.HasAudio();
-  }
-
-  virtual bool HasVideo() override {
-    return mInfo.HasVideo();
-  }
-
   layers::ImageContainer* GetImageContainer() { return mDecoder->GetImageContainer(); }
 
   virtual bool IsMediaSeekable() override;
 
 private:
-
+  bool HasAudio() { return mInfo.HasAudio(); }
+  bool HasVideo() { return mInfo.HasVideo(); }
   void ReadAndPushData(guint aLength);
   RefPtr<layers::PlanarYCbCrImage> GetImageFromBuffer(GstBuffer* aBuffer);
   void CopyIntoImageBuffer(GstBuffer *aBuffer, GstBuffer** aOutBuffer, RefPtr<layers::PlanarYCbCrImage> &image);
diff --git a/dom/media/ogg/OggReader.h b/dom/media/ogg/OggReader.h
index 5397e5296e07..bb715d4ced1a 100644
--- a/dom/media/ogg/OggReader.h
+++ b/dom/media/ogg/OggReader.h
@@ -60,15 +60,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                 int64_t aTimeThreshold) override;
 
-  virtual bool HasAudio() override {
-    return (mVorbisState != 0 && mVorbisState->mActive) ||
-           (mOpusState != 0 && mOpusState->mActive);
-  }
-
-  virtual bool HasVideo() override {
-    return mTheoraState != 0 && mTheoraState->mActive;
-  }
-
   virtual nsresult ReadMetadata(MediaInfo* aInfo,
                                 MetadataTags** aTags) override;
   virtual RefPtr<SeekPromise>
@@ -78,6 +69,15 @@ public:
   virtual bool IsMediaSeekable() override;
 
 private:
+  bool HasAudio() {
+    return (mVorbisState != 0 && mVorbisState->mActive) ||
+           (mOpusState != 0 && mOpusState->mActive);
+  }
+
+  bool HasVideo() {
+    return mTheoraState != 0 && mTheoraState->mActive;
+  }
+
   // TODO: DEPRECATED. This uses synchronous decoding.
   // Stores the presentation time of the first frame we'd be able to play if
   // we started playback at the current position. Returns the first video
diff --git a/dom/media/omx/MediaCodecReader.h b/dom/media/omx/MediaCodecReader.h
index f3be13e4adc3..3e8c86350afd 100644
--- a/dom/media/omx/MediaCodecReader.h
+++ b/dom/media/omx/MediaCodecReader.h
@@ -86,9 +86,6 @@ public:
   // Disptach a DecodeAduioDataTask to decode video data.
   virtual RefPtr<AudioDataPromise> RequestAudioData() override;
 
-  virtual bool HasAudio();
-  virtual bool HasVideo();
-
   virtual RefPtr<MediaDecoderReader::MetadataPromise> AsyncReadMetadata() override;
 
   // Moves the decode head to aTime microseconds. aStartTime and aEndTime
@@ -181,6 +178,8 @@ protected:
   MozPromiseHolder<MediaResourcePromise> mMediaResourcePromise;
 
 private:
+  virtual bool HasAudio() override;
+  virtual bool HasVideo() override;
 
   // An intermediary class that can be managed by android::sp<T>.
   // Redirect codecReserved() and codecCanceled() to MediaCodecReader.
diff --git a/dom/media/omx/MediaOmxCommonReader.h b/dom/media/omx/MediaOmxCommonReader.h
index d70f3c7cea52..022ff52f37ae 100644
--- a/dom/media/omx/MediaOmxCommonReader.h
+++ b/dom/media/omx/MediaOmxCommonReader.h
@@ -49,6 +49,10 @@ protected:
   android::MediaStreamSource* mStreamSource;
   // Get value from the preferece, if true, we stop the audio offload.
   bool IsMonoAudioEnabled();
+
+private:
+  virtual bool HasAudio() = 0;
+  virtual bool HasVideo() = 0;
 };
 
 } // namespace mozilla
diff --git a/dom/media/omx/MediaOmxReader.h b/dom/media/omx/MediaOmxReader.h
index 155d66b05d82..2922adb4f967 100644
--- a/dom/media/omx/MediaOmxReader.h
+++ b/dom/media/omx/MediaOmxReader.h
@@ -85,16 +85,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                 int64_t aTimeThreshold);
 
-  virtual bool HasAudio()
-  {
-    return mHasAudio;
-  }
-
-  virtual bool HasVideo()
-  {
-    return mHasVideo;
-  }
-
   virtual void ReleaseMediaResources() override;
 
   virtual RefPtr<MediaDecoderReader::MetadataPromise> AsyncReadMetadata() override;
@@ -118,6 +108,9 @@ private:
   class ProcessCachedDataTask;
   class NotifyDataArrivedRunnable;
 
+  virtual bool HasAudio() override { return mHasAudio; }
+  virtual bool HasVideo() override { return mHasVideo; }
+
   bool IsShutdown() {
     MutexAutoLock lock(mShutdownMutex);
     return mIsShutdown;
diff --git a/dom/media/raw/RawReader.h b/dom/media/raw/RawReader.h
index e0481e901329..d4ff7f72e76d 100644
--- a/dom/media/raw/RawReader.h
+++ b/dom/media/raw/RawReader.h
@@ -26,16 +26,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                   int64_t aTimeThreshold) override;
 
-  virtual bool HasAudio() override
-  {
-    return false;
-  }
-
-  virtual bool HasVideo() override
-  {
-    return true;
-  }
-
   virtual nsresult ReadMetadata(MediaInfo* aInfo,
                                 MetadataTags** aTags) override;
   virtual RefPtr<SeekPromise>
diff --git a/dom/media/wave/WaveReader.h b/dom/media/wave/WaveReader.h
index 468e20a3fcf1..cc9708152db5 100644
--- a/dom/media/wave/WaveReader.h
+++ b/dom/media/wave/WaveReader.h
@@ -26,16 +26,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                   int64_t aTimeThreshold) override;
 
-  virtual bool HasAudio() override
-  {
-    return true;
-  }
-
-  virtual bool HasVideo() override
-  {
-    return false;
-  }
-
   virtual nsresult ReadMetadata(MediaInfo* aInfo,
                                 MetadataTags** aTags) override;
   virtual RefPtr<SeekPromise>
diff --git a/dom/media/webm/WebMReader.h b/dom/media/webm/WebMReader.h
index 3434eef9618c..ea14e5ecbc35 100644
--- a/dom/media/webm/WebMReader.h
+++ b/dom/media/webm/WebMReader.h
@@ -69,6 +69,14 @@ protected:
   ~WebMReader();
 
 public:
+  // Returns a pointer to the decoder.
+  AbstractMediaDecoder* GetDecoder()
+  {
+    return mDecoder;
+  }
+
+  MediaInfo GetMediaInfo() { return mInfo; }
+
   virtual RefPtr<ShutdownPromise> Shutdown() override;
   virtual nsresult Init() override;
   virtual nsresult ResetDecode() override;
@@ -77,18 +85,6 @@ public:
   virtual bool DecodeVideoFrame(bool &aKeyframeSkip,
                                 int64_t aTimeThreshold) override;
 
-  virtual bool HasAudio() override
-  {
-    MOZ_ASSERT(OnTaskQueue());
-    return mHasAudio;
-  }
-
-  virtual bool HasVideo() override
-  {
-    MOZ_ASSERT(OnTaskQueue());
-    return mHasVideo;
-  }
-
   virtual RefPtr<MetadataPromise> AsyncReadMetadata() override;
 
   virtual RefPtr<SeekPromise>