--- a/dom/media/MediaDecoderReader.cpp
+++ b/dom/media/MediaDecoderReader.cpp
@@ -343,24 +343,16 @@ MediaDecoderReader::RequestAudioData()
     mHitAudioDecodeError = false;
   } else {
     MOZ_ASSERT(false, "Dropping this promise on the floor");
   }
 
   return p;
 }
 
-void
-MediaDecoderReader::BreakCycles()
-{
-  // Nothing left to do here these days. We keep this method around so that, if
-  // we need it, we don't have to make all of the subclass implementations call
-  // the superclass method again.
-}
-
 RefPtr<ShutdownPromise>
 MediaDecoderReader::Shutdown()
 {
   MOZ_ASSERT(OnTaskQueue());
   mShutdown = true;
 
   mBaseAudioPromise.RejectIfExists(END_OF_STREAM, __func__);
   mBaseVideoPromise.RejectIfExists(END_OF_STREAM, __func__);

--- a/dom/media/MediaDecoderReader.h
+++ b/dom/media/MediaDecoderReader.h
@@ -98,20 +98,16 @@ public:
 
   // Initializes the reader, returns NS_OK on success, or NS_ERROR_FAILURE
   // on failure.
   virtual nsresult Init() { return NS_OK; }
 
   // Release media resources they should be released in dormant state
   // The reader can be made usable again by calling ReadMetadata().
   virtual void ReleaseMediaResources() {}
-  // Breaks reference-counted cycles. Called during shutdown.
-  // WARNING: If you override this, you must call the base implementation
-  // in your override.
-  virtual void BreakCycles();
 
   // Destroys the decoding state. The reader cannot be made usable again.
   // This is different from ReleaseMediaResources() as it is irreversable,
   // whereas ReleaseMediaResources() is.  Must be called on the decode
   // thread.
   virtual RefPtr<ShutdownPromise> Shutdown();
 
   virtual bool OnTaskQueue() const

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -210,17 +210,16 @@ public:
       }
     });
     OwnerThread()->Dispatch(r.forget());
   }
 
   // Drop reference to mResource. Only called during shutdown dance.
   void BreakCycles() {
     MOZ_ASSERT(NS_IsMainThread());
-    mReader->BreakCycles();
     mResource = nullptr;
   }
 
   TimedMetadataEventSource& TimedMetadataEvent() {
     return mMetadataManager.TimedMetadataEvent();
   }
 
   MediaEventSource<void>& OnMediaNotSeekable() {

--- a/dom/media/webaudio/MediaBufferDecoder.cpp
+++ b/dom/media/webaudio/MediaBufferDecoder.cpp
@@ -140,17 +140,16 @@ private:
   void AllocateBuffer();
   void CallbackTheResult();
 
   void Cleanup()
   {
     MOZ_ASSERT(NS_IsMainThread());
     // MediaDecoderReader expects that BufferDecoder is alive.
     // Destruct MediaDecoderReader first.
-    mDecoderReader->BreakCycles();
     mDecoderReader = nullptr;
     mBufferDecoder = nullptr;
     JS_free(nullptr, mBuffer);
   }
 
 private:
   nsCString mContentType;
   uint8_t* mBuffer;