--- a/dom/media/MediaDecoderReader.cpp
+++ b/dom/media/MediaDecoderReader.cpp
@@ -32,47 +32,16 @@ extern LazyLogModule gMediaDecoderLog;
 #undef FMT
 #undef DECODER_LOG
 #undef DECODER_WARN
 
 #define FMT(x, ...) "Decoder=%p " x, mDecoder, ##__VA_ARGS__
 #define DECODER_LOG(...) MOZ_LOG(gMediaDecoderLog, LogLevel::Debug,   (FMT(__VA_ARGS__)))
 #define DECODER_WARN(...) NS_WARNING(nsPrintfCString(FMT(__VA_ARGS__)).get())
 
-class VideoQueueMemoryFunctor : public nsDequeFunctor {
-public:
-  VideoQueueMemoryFunctor() : mSize(0) {}
-
-  MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf);
-
-  virtual void* operator()(void* aObject) {
-    const VideoData* v = static_cast<const VideoData*>(aObject);
-    mSize += v->SizeOfIncludingThis(MallocSizeOf);
-    return nullptr;
-  }
-
-  size_t mSize;
-};
-
-
-class AudioQueueMemoryFunctor : public nsDequeFunctor {
-public:
-  AudioQueueMemoryFunctor() : mSize(0) {}
-
-  MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf);
-
-  virtual void* operator()(void* aObject) {
-    const AudioData* audioData = static_cast<const AudioData*>(aObject);
-    mSize += audioData->SizeOfIncludingThis(MallocSizeOf);
-    return nullptr;
-  }
-
-  size_t mSize;
-};
-
 MediaDecoderReader::MediaDecoderReader(MediaDecoderReaderInit& aInit)
   : mDecoder(aInit.mDecoder)
   , mTaskQueue(new TaskQueue(
       GetMediaThreadPool(MediaThreadType::PLAYBACK),
       "MediaDecoderReader::mTaskQueue",
       /* aSupportsTailDispatch = */ true))
   , mBuffered(mTaskQueue, TimeIntervals(), "MediaDecoderReader::mBuffered (Canonical)")
   , mShutdown(false)

--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -3983,26 +3983,70 @@ void MediaDecoderStateMachine::RemoveOut
       NewRunnableMethod<bool>("MediaDecoderStateMachine::SetAudioCaptured",
                               this,
                               &MediaDecoderStateMachine::SetAudioCaptured,
                               false);
     OwnerThread()->Dispatch(r.forget());
   }
 }
 
+class VideoQueueMemoryFunctor : public nsDequeFunctor
+{
+public:
+  VideoQueueMemoryFunctor()
+    : mSize(0)
+  {
+  }
+
+  MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf);
+
+  virtual void* operator()(void* aObject)
+  {
+    const VideoData* v = static_cast<const VideoData*>(aObject);
+    mSize += v->SizeOfIncludingThis(MallocSizeOf);
+    return nullptr;
+  }
+
+  size_t mSize;
+};
+
+class AudioQueueMemoryFunctor : public nsDequeFunctor
+{
+public:
+  AudioQueueMemoryFunctor()
+    : mSize(0)
+  {
+  }
+
+  MOZ_DEFINE_MALLOC_SIZE_OF(MallocSizeOf);
+
+  virtual void* operator()(void* aObject)
+  {
+    const AudioData* audioData = static_cast<const AudioData*>(aObject);
+    mSize += audioData->SizeOfIncludingThis(MallocSizeOf);
+    return nullptr;
+  }
+
+  size_t mSize;
+};
+
 size_t
 MediaDecoderStateMachine::SizeOfVideoQueue() const
 {
-  return mReader->SizeOfVideoQueueInBytes();
+  VideoQueueMemoryFunctor functor;
+  mVideoQueue.LockedForEach(functor);
+  return functor.mSize;
 }
 
 size_t
 MediaDecoderStateMachine::SizeOfAudioQueue() const
 {
-  return mReader->SizeOfAudioQueueInBytes();
+  AudioQueueMemoryFunctor functor;
+  mAudioQueue.LockedForEach(functor);
+  return functor.mSize;
 }
 
 AbstractCanonical<media::TimeIntervals>*
 MediaDecoderStateMachine::CanonicalBuffered() const
 {
   return mReader->CanonicalBuffered();
 }