--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -387,17 +387,16 @@ MediaDecoder::MediaDecoder(MediaDecoderI
   , mMinimizePreroll(aInit.mMinimizePreroll)
   , mFiredMetadataLoaded(false)
   , mIsDocumentVisible(false)
   , mElementVisibility(Visibility::UNTRACKED)
   , mIsElementInTree(false)
   , mForcedHidden(false)
   , mHasSuspendTaint(aInit.mHasSuspendTaint)
   , mPlaybackRate(aInit.mPlaybackRate)
-  , INIT_MIRROR(mStateMachineIsShutdown, true)
   , INIT_MIRROR(mBuffered, TimeIntervals())
   , INIT_MIRROR(mNextFrameStatus, MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE)
   , INIT_MIRROR(mCurrentPosition, TimeUnit::Zero())
   , INIT_MIRROR(mStateMachineDuration, NullableTimeUnit())
   , INIT_MIRROR(mPlaybackPosition, 0)
   , INIT_MIRROR(mIsAudioDataAudible, false)
   , INIT_CANONICAL(mVolume, aInit.mVolume)
   , INIT_CANONICAL(mPreservesPitch, aInit.mPreservesPitch)
@@ -1457,30 +1456,28 @@ MediaDecoder::SetLooping(bool aLooping)
 
 void
 MediaDecoder::ConnectMirrors(MediaDecoderStateMachine* aObject)
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(aObject);
   mStateMachineDuration.Connect(aObject->CanonicalDuration());
   mBuffered.Connect(aObject->CanonicalBuffered());
-  mStateMachineIsShutdown.Connect(aObject->CanonicalIsShutdown());
   mNextFrameStatus.Connect(aObject->CanonicalNextFrameStatus());
   mCurrentPosition.Connect(aObject->CanonicalCurrentPosition());
   mPlaybackPosition.Connect(aObject->CanonicalPlaybackOffset());
   mIsAudioDataAudible.Connect(aObject->CanonicalIsAudioDataAudible());
 }
 
 void
 MediaDecoder::DisconnectMirrors()
 {
   MOZ_ASSERT(NS_IsMainThread());
   mStateMachineDuration.DisconnectIfConnected();
   mBuffered.DisconnectIfConnected();
-  mStateMachineIsShutdown.DisconnectIfConnected();
   mNextFrameStatus.DisconnectIfConnected();
   mCurrentPosition.DisconnectIfConnected();
   mPlaybackPosition.DisconnectIfConnected();
   mIsAudioDataAudible.DisconnectIfConnected();
 }
 
 void
 MediaDecoder::SetStateMachine(MediaDecoderStateMachine* aStateMachine)

--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -739,19 +739,16 @@ protected:
   MediaEventListener mOnPlaybackErrorEvent;
   MediaEventListener mOnDecoderDoctorEvent;
   MediaEventListener mOnMediaNotSeekable;
 
 protected:
   // PlaybackRate and pitch preservation status we should start at.
   double mPlaybackRate;
 
-  // Whether the state machine is shut down.
-  Mirror<bool> mStateMachineIsShutdown;
-
   // Buffered range, mirrored from the reader.
   Mirror<media::TimeIntervals> mBuffered;
 
   // NextFrameStatus, mirrored from the state machine.
   Mirror<MediaDecoderOwner::NextFrameStatus> mNextFrameStatus;
 
   // NB: Don't use mCurrentPosition directly, but rather CurrentPosition().
   Mirror<media::TimeUnit> mCurrentPosition;