--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -1253,16 +1253,50 @@ MediaDecoderStateMachine::Shutdown()
 
   // To break the cycle-reference between MediaDecoderReaderWrapper and MDSM.
   CancelMediaDecoderReaderWrapperCallback();
 
   Reset();
 
   mMediaSink->Shutdown();
 
+  // Prevent dangling pointers by disconnecting the listeners.
+  mAudioQueueListener.Disconnect();
+  mVideoQueueListener.Disconnect();
+  mMetadataManager.Disconnect();
+
+  // Disconnect canonicals and mirrors before shutting down our task queue.
+  mBuffered.DisconnectIfConnected();
+  mIsReaderSuspended.DisconnectIfConnected();
+  mEstimatedDuration.DisconnectIfConnected();
+  mExplicitDuration.DisconnectIfConnected();
+  mPlayState.DisconnectIfConnected();
+  mNextPlayState.DisconnectIfConnected();
+  mVolume.DisconnectIfConnected();
+  mLogicalPlaybackRate.DisconnectIfConnected();
+  mPreservesPitch.DisconnectIfConnected();
+  mSameOriginMedia.DisconnectIfConnected();
+  mMediaPrincipalHandle.DisconnectIfConnected();
+  mPlaybackBytesPerSecond.DisconnectIfConnected();
+  mPlaybackRateReliable.DisconnectIfConnected();
+  mDecoderPosition.DisconnectIfConnected();
+  mMediaSeekable.DisconnectIfConnected();
+  mMediaSeekableOnlyInBufferedRanges.DisconnectIfConnected();
+  mIsVisible.DisconnectIfConnected();
+
+  mDuration.DisconnectAll();
+  mIsShutdown.DisconnectAll();
+  mNextFrameStatus.DisconnectAll();
+  mCurrentPosition.DisconnectAll();
+  mPlaybackOffset.DisconnectAll();
+  mIsAudioDataAudible.DisconnectAll();
+
+  // Shut down the watch manager to stop further notifications.
+  mWatchManager.Shutdown();
+
   DECODER_LOG("Shutdown started");
 
   // Put a task in the decode queue to shutdown the reader.
   // the queue to spin down.
   return mReader->Shutdown()
     ->Then(OwnerThread(), __func__, this,
            &MediaDecoderStateMachine::FinishShutdown,
            &MediaDecoderStateMachine::FinishShutdown)
@@ -2220,55 +2254,16 @@ MediaDecoderStateMachine::BeginShutdown(
   return InvokeAsync(OwnerThread(), this, __func__,
                      &MediaDecoderStateMachine::Shutdown);
 }
 
 RefPtr<ShutdownPromise>
 MediaDecoderStateMachine::FinishShutdown()
 {
   MOZ_ASSERT(OnTaskQueue());
-
-  // The reader's listeners hold references to the state machine,
-  // creating a cycle which keeps the state machine and its shared
-  // thread pools alive. So break it here.
-
-  // Prevent dangling pointers by disconnecting the listeners.
-  mAudioQueueListener.Disconnect();
-  mVideoQueueListener.Disconnect();
-  mMetadataManager.Disconnect();
-
-  // Disconnect canonicals and mirrors before shutting down our task queue.
-  mBuffered.DisconnectIfConnected();
-  mIsReaderSuspended.DisconnectIfConnected();
-  mEstimatedDuration.DisconnectIfConnected();
-  mExplicitDuration.DisconnectIfConnected();
-  mPlayState.DisconnectIfConnected();
-  mNextPlayState.DisconnectIfConnected();
-  mVolume.DisconnectIfConnected();
-  mLogicalPlaybackRate.DisconnectIfConnected();
-  mPreservesPitch.DisconnectIfConnected();
-  mSameOriginMedia.DisconnectIfConnected();
-  mMediaPrincipalHandle.DisconnectIfConnected();
-  mPlaybackBytesPerSecond.DisconnectIfConnected();
-  mPlaybackRateReliable.DisconnectIfConnected();
-  mDecoderPosition.DisconnectIfConnected();
-  mMediaSeekable.DisconnectIfConnected();
-  mMediaSeekableOnlyInBufferedRanges.DisconnectIfConnected();
-  mIsVisible.DisconnectIfConnected();
-
-  mDuration.DisconnectAll();
-  mIsShutdown.DisconnectAll();
-  mNextFrameStatus.DisconnectAll();
-  mCurrentPosition.DisconnectAll();
-  mPlaybackOffset.DisconnectAll();
-  mIsAudioDataAudible.DisconnectAll();
-
-  // Shut down the watch manager before shutting down our task queue.
-  mWatchManager.Shutdown();
-
   MOZ_ASSERT(mState == DECODER_STATE_SHUTDOWN,
              "How did we escape from the shutdown state?");
   DECODER_LOG("Shutting down state machine task queue");
   return OwnerThread()->BeginShutdown();
 }
 
 void
 MediaDecoderStateMachine::RunStateMachine()