--- a/dom/media/ChannelMediaDecoder.cpp
+++ b/dom/media/ChannelMediaDecoder.cpp
@@ -482,16 +482,25 @@ ChannelMediaDecoder::ShouldThrottleDownl
   if (!stats.mDownloadRateReliable || !stats.mPlaybackRateReliable) {
     return false;
   }
   uint32_t factor =
     std::max(2u, Preferences::GetUint("media.throttle-factor", 2));
   return stats.mDownloadRate > factor * stats.mPlaybackRate;
 }
 
+void
+ChannelMediaDecoder::AddSizeOfResources(ResourceSizes* aSizes)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mResource) {
+    aSizes->mByteSize += mResource->SizeOfIncludingThis(aSizes->mMallocSizeOf);
+  }
+}
+
 already_AddRefed<nsIPrincipal>
 ChannelMediaDecoder::GetCurrentPrincipal()
 {
   MOZ_ASSERT(NS_IsMainThread());
   return mResource ? mResource->GetCurrentPrincipal() : nullptr;
 }
 
 bool

--- a/dom/media/ChannelMediaDecoder.h
+++ b/dom/media/ChannelMediaDecoder.h
@@ -73,16 +73,17 @@ public:
 
   // Create a new decoder of the same type as this one.
   already_AddRefed<ChannelMediaDecoder> Clone(MediaDecoderInit& aInit);
 
   nsresult Load(nsIChannel* aChannel,
                 bool aIsPrivateBrowsing,
                 nsIStreamListener** aStreamListener);
 
+  void AddSizeOfResources(ResourceSizes* aSizes) override;
   already_AddRefed<nsIPrincipal> GetCurrentPrincipal() override;
   bool IsTransportSeekable() override;
   void SetLoadInBackground(bool aLoadInBackground) override;
   void Suspend() override;
   void Resume() override;
 
 private:
   MediaResource* GetResource() const override final;

--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -1331,25 +1331,16 @@ MediaDecoder::SizeOfAudioQueue()
 {
   MOZ_ASSERT(NS_IsMainThread());
   if (mDecoderStateMachine) {
     return mDecoderStateMachine->SizeOfAudioQueue();
   }
   return 0;
 }
 
-void MediaDecoder::AddSizeOfResources(ResourceSizes* aSizes)
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  if (GetResource()) {
-    aSizes->mByteSize +=
-      GetResource()->SizeOfIncludingThis(aSizes->mMallocSizeOf);
-  }
-}
-
 void
 MediaDecoder::NotifyDataArrivedInternal()
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_DIAGNOSTIC_ASSERT(!IsShutdown());
   mReader->OwnerThread()->Dispatch(
     NewRunnableMethod("MediaFormatReader::NotifyDataArrived",
                       mReader.get(),

--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -270,17 +270,17 @@ private:
     ~ResourceSizes()
     {
       mCallback.ResolveIfExists(mByteSize, __func__);
     }
 
     MozPromiseHolder<SizeOfPromise> mCallback;
   };
 
-  virtual void AddSizeOfResources(ResourceSizes* aSizes);
+  virtual void AddSizeOfResources(ResourceSizes* aSizes) = 0;
 
   VideoFrameContainer* GetVideoFrameContainer()
   {
     return mVideoFrameContainer;
   }
 
   layers::ImageContainer* GetImageContainer();
 

--- a/dom/media/hls/HLSDecoder.cpp
+++ b/dom/media/hls/HLSDecoder.cpp
@@ -87,16 +87,25 @@ HLSDecoder::Load(nsIChannel* aChannel)
   }
 
   SetStateMachine(CreateStateMachine());
   NS_ENSURE_TRUE(GetStateMachine(), NS_ERROR_FAILURE);
 
   return InitializeStateMachine();
 }
 
+void
+HLSDecoder::AddSizeOfResources(ResourceSizes* aSizes)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mResource) {
+    aSizes->mByteSize += mResource->SizeOfIncludingThis(aSizes->mMallocSizeOf);
+  }
+}
+
 already_AddRefed<nsIPrincipal>
 HLSDecoder::GetCurrentPrincipal()
 {
   MOZ_ASSERT(NS_IsMainThread());
   return mResource ? mResource->GetCurrentPrincipal() : nullptr;
 }
 
 nsresult

--- a/dom/media/hls/HLSDecoder.h
+++ b/dom/media/hls/HLSDecoder.h
@@ -32,16 +32,17 @@ public:
   static bool IsSupportedType(const MediaContainerType& aContainerType);
 
   nsresult Load(nsIChannel* aChannel);
 
   nsresult Play() override;
 
   void Pause() override;
 
+  void AddSizeOfResources(ResourceSizes* aSizes) override;
   already_AddRefed<nsIPrincipal> GetCurrentPrincipal() override;
   bool IsTransportSeekable() override { return true; }
   void Suspend() override;
   void Resume() override;
 
 private:
   MediaResource* GetResource() const override final;
 

--- a/dom/media/hls/HLSResource.h
+++ b/dom/media/hls/HLSResource.h
@@ -78,33 +78,33 @@ public:
   }
 
   java::GeckoHLSResourceWrapper::GlobalRef GetResourceWrapper() {
     return mHLSResourceWrapper;
   }
 
   void Detach() { mDecoder = nullptr; }
 
-private:
-  friend class HLSResourceCallbacksSupport;
-
-  void onDataAvailable();
-  void onError(int aErrorCode);
-
   size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
   {
     size_t size = MediaResource::SizeOfExcludingThis(aMallocSizeOf);
     return size;
   }
 
   size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
 
+private:
+  friend class HLSResourceCallbacksSupport;
+
+  void onDataAvailable();
+  void onError(int aErrorCode);
+
   HLSDecoder* mDecoder;
   nsCOMPtr<nsIChannel> mChannel;
   nsCOMPtr<nsIURI> mURI;
   java::GeckoHLSResourceWrapper::GlobalRef mHLSResourceWrapper;
   java::GeckoHLSResourceWrapper::Callbacks::GlobalRef mJavaCallbacks;
   RefPtr<HLSResourceCallbacksSupport> mCallbackSupport;
 };