diff --git a/dom/media/MediaDecoderReader.cpp b/dom/media/MediaDecoderReader.cpp
index 26698623d5b5..44ca2d92278d 100644
--- a/dom/media/MediaDecoderReader.cpp
+++ b/dom/media/MediaDecoderReader.cpp
@@ -283,28 +283,18 @@ MediaDecoderReader::BreakCycles()
   mTaskQueue = nullptr;
 }
 
-nsRefPtr<ShutdownPromise>
+void
 MediaDecoderReader::Shutdown()
 {
   MOZ_ASSERT(OnDecodeThread());
   mShutdown = true;
   ReleaseMediaResources();
-  nsRefPtr<ShutdownPromise> p;
-
-  // Spin down the task queue if necessary. We wait until BreakCycles to null
-  // out mTaskQueue, since otherwise any remaining tasks could crash when they
-  // invoke GetTaskQueue()->IsCurrentThreadIn().
   if (mTaskQueue && !mTaskQueueIsBorrowed) {
-    // If we own our task queue, shutdown ends when the task queue is done.
-    p = mTaskQueue->BeginShutdown();
-  } else {
-    // If we don't own our task queue, we resolve immediately (though
-    // asynchronously).
-    p = new ShutdownPromise(__func__);
-    p->Resolve(true, __func__);
+    // We may be running in the task queue ourselves, so we don't block this
+    // thread on task queue draining, since that would deadlock.
+    mTaskQueue->BeginShutdown();
   }
-
-  return p;
+  mTaskQueue = nullptr;
 }
 
 AudioDecodeRendezvous::AudioDecodeRendezvous()
diff --git a/dom/media/MediaDecoderReader.h b/dom/media/MediaDecoderReader.h
index eaee9c0c33a3..508ee8fa8bd7 100644
--- a/dom/media/MediaDecoderReader.h
+++ b/dom/media/MediaDecoderReader.h
@@ -65,7 +65,7 @@ public:
   // This is different from ReleaseMediaResources() as it is irreversable,
   // whereas ReleaseMediaResources() is.  Must be called on the decode
   // thread.
-  virtual nsRefPtr<ShutdownPromise> Shutdown();
+  virtual void Shutdown();
 
   virtual void SetCallback(RequestSampleCallback* aDecodedSampleCallback);
   MediaTaskQueue* EnsureTaskQueue();
diff --git a/dom/media/MediaDecoderStateMachine.cpp b/dom/media/MediaDecoderStateMachine.cpp
index 9f899eb2215d..798f0860ba38 100644
--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -2470,53 +2470,6 @@ private:
   nsRefPtr<MediaDecoderStateMachine> mStateMachine;
 };
 
-void
-MediaDecoderStateMachine::ShutdownReader()
-{
-  MOZ_ASSERT(OnDecodeThread());
-  mReader->Shutdown()->Then(GetStateMachineThread(), __func__, this,
-                            &MediaDecoderStateMachine::FinishShutdown,
-                            &MediaDecoderStateMachine::FinishShutdown);
-}
-
-void
-MediaDecoderStateMachine::FinishShutdown(bool aSuccess)
-{
-  MOZ_ASSERT(OnStateMachineThread());
-  MOZ_ASSERT(aSuccess);
-  ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
-
-  // 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.
-  AudioQueue().ClearListeners();
-  VideoQueue().ClearListeners();
-
-  // Now that those threads are stopped, there's no possibility of
-  // mPendingWakeDecoder being needed again. Revoke it.
-  mPendingWakeDecoder = nullptr;
-
-  MOZ_ASSERT(mState == DECODER_STATE_SHUTDOWN,
-             "How did we escape from the shutdown state?");
-  // We must daisy-chain these events to destroy the decoder. We must
-  // destroy the decoder on the main thread, but we can't destroy the
-  // decoder while this thread holds the decoder monitor. We can't
-  // dispatch an event to the main thread to destroy the decoder from
-  // here, as the event may run before the dispatch returns, and we
-  // hold the decoder monitor here. We also want to guarantee that the
-  // state machine is destroyed on the main thread, and so the
-  // event runner running this function (which holds a reference to the
-  // state machine) needs to finish and be released in order to allow
-  // that. So we dispatch an event to run after this event runner has
-  // finished and released its monitor/references. That event then will
-  // dispatch an event to the main thread to release the decoder and
-  // state machine.
-  GetStateMachineThread()->Dispatch(
-    new nsDispatchDisposeEvent(mDecoder, this), NS_DISPATCH_NORMAL);
-
-  DECODER_LOG("Dispose Event Dispatched");
-}
-
 nsresult MediaDecoderStateMachine::RunStateMachine()
 {
   AssertCurrentThreadInMonitor();
@@ -2533,14 +2486,47 @@ nsresult MediaDecoderStateMachine::RunStateMachine()
       StopAudioThread();
       FlushDecoding();
 
-      // Put a task in the decode queue to shutdown the reader.
+      // Put a task in the decode queue to shutdown the reader and wait for
       // the queue to spin down.
-      RefPtr<nsIRunnable> task;
-      task = NS_NewRunnableMethod(this, &MediaDecoderStateMachine::ShutdownReader);
-      DebugOnly<nsresult> rv = DecodeTaskQueue()->Dispatch(task);
-      MOZ_ASSERT(NS_SUCCEEDED(rv));
+      {
+        RefPtr<nsIRunnable> task;
+        task = NS_NewRunnableMethod(mReader, &MediaDecoderReader::Shutdown);
+        nsRefPtr<MediaTaskQueue> queue = DecodeTaskQueue();
+        DebugOnly<nsresult> rv = queue->Dispatch(task);
+        MOZ_ASSERT(NS_SUCCEEDED(rv));
+        ReentrantMonitorAutoExit exitMon(mDecoder->GetReentrantMonitor());
+        queue->AwaitShutdownAndIdle();
+      }
 
-      DECODER_LOG("Shutdown started");
+      // 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.
+      AudioQueue().ClearListeners();
+      VideoQueue().ClearListeners();
+
+      // Now that those threads are stopped, there's no possibility of
+      // mPendingWakeDecoder being needed again. Revoke it.
+      mPendingWakeDecoder = nullptr;
+
+      MOZ_ASSERT(mState == DECODER_STATE_SHUTDOWN,
+                 "How did we escape from the shutdown state?");
+      // We must daisy-chain these events to destroy the decoder. We must
+      // destroy the decoder on the main thread, but we can't destroy the
+      // decoder while this thread holds the decoder monitor. We can't
+      // dispatch an event to the main thread to destroy the decoder from
+      // here, as the event may run before the dispatch returns, and we
+      // hold the decoder monitor here. We also want to guarantee that the
+      // state machine is destroyed on the main thread, and so the
+      // event runner running this function (which holds a reference to the
+      // state machine) needs to finish and be released in order to allow
+      // that. So we dispatch an event to run after this event runner has
+      // finished and released its monitor/references. That event then will
+      // dispatch an event to the main thread to release the decoder and
+      // state machine.
+      GetStateMachineThread()->Dispatch(
+        new nsDispatchDisposeEvent(mDecoder, this), NS_DISPATCH_NORMAL);
+
+      DECODER_LOG("SHUTDOWN OK");
       return NS_OK;
     }
 
diff --git a/dom/media/MediaDecoderStateMachine.h b/dom/media/MediaDecoderStateMachine.h
index d99195c703ad..dfcbf5734a44 100644
--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -162,8 +162,6 @@ public:
   // Set/Unset dormant state.
   void SetDormant(bool aDormant);
   void Shutdown();
-  void ShutdownReader();
-  void FinishShutdown(bool aSuccess);
 
   // Called from the main thread to get the duration. The decoder monitor
   // must be obtained before calling this. It is in units of microseconds.
diff --git a/dom/media/MediaTaskQueue.cpp b/dom/media/MediaTaskQueue.cpp
index 782356121386..7afd582da4ac 100644
--- a/dom/media/MediaTaskQueue.cpp
+++ b/dom/media/MediaTaskQueue.cpp
@@ -134,17 +134,12 @@ MediaTaskQueue::AwaitShutdownAndIdle()
   AwaitIdleLocked();
 }
 
-nsRefPtr<ShutdownPromise>
+void
 MediaTaskQueue::BeginShutdown()
 {
   MonitorAutoLock mon(mQueueMonitor);
   mIsShutdown = true;
-  nsRefPtr<ShutdownPromise> p = mShutdownPromise.Ensure(__func__);
-  if (!mIsRunning) {
-    mShutdownPromise.Resolve(true, __func__);
-  }
   mon.NotifyAll();
-  return p;
 }
 
 nsresult
@@ -213,7 +208,6 @@ MediaTaskQueue::Runner::Run()
     mQueue->mRunningThread = NS_GetCurrentThread();
     if (mQueue->mTasks.size() == 0) {
       mQueue->mIsRunning = false;
-      mQueue->mShutdownPromise.ResolveIfExists(true, __func__);
       mon.NotifyAll();
       return NS_OK;
     }
@@ -241,7 +235,6 @@ MediaTaskQueue::Runner::Run()
     if (mQueue->mTasks.size() == 0) {
       // No more events to run. Exit the task runner.
       mQueue->mIsRunning = false;
-      mQueue->mShutdownPromise.ResolveIfExists(true, __func__);
       mon.NotifyAll();
       mQueue->mRunningThread = nullptr;
       return NS_OK;
diff --git a/dom/media/MediaTaskQueue.h b/dom/media/MediaTaskQueue.h
index ce3827b52cfe..1027ed56ef1f 100644
--- a/dom/media/MediaTaskQueue.h
+++ b/dom/media/MediaTaskQueue.h
@@ -12,7 +12,6 @@
 #include "mozilla/Monitor.h"
 #include "SharedThreadPool.h"
 #include "nsThreadUtils.h"
-#include "MediaPromise.h"
 
 class nsIRunnable;
 
@@ -20,8 +19,6 @@ namespace mozilla {
 
 class SharedThreadPool;
 
-typedef MediaPromise<bool, bool> ShutdownPromise;
-
 // Abstracts executing runnables in order in a thread pool. The runnables
 // dispatched to the MediaTaskQueue will be executed in the order in which
 // they're received, and are guaranteed to not be executed concurrently.
@@ -53,9 +50,7 @@ public:
   // remain alive at least until all the events are drained, because the Runners
   // hold a strong reference to the task queue, and one of them is always held
   // by the threadpool event queue when the task queue is non-empty.
-  //
-  // The returned promise is resolved when the queue goes empty.
-  nsRefPtr<ShutdownPromise> BeginShutdown();
+  void BeginShutdown();
 
   // Blocks until all task finish executing.
   void AwaitIdle();
@@ -110,7 +105,6 @@ private:
 
   // True if we've started our shutdown process.
   bool mIsShutdown;
-  MediaPromiseHolder<ShutdownPromise> mShutdownPromise;
 
   class MOZ_STACK_CLASS AutoSetFlushing
   {
diff --git a/dom/media/android/AndroidMediaReader.cpp b/dom/media/android/AndroidMediaReader.cpp
index cf8c463f1ad2..bd2d32ca8f2f 100644
--- a/dom/media/android/AndroidMediaReader.cpp
+++ b/dom/media/android/AndroidMediaReader.cpp
@@ -99,8 +99,7 @@ nsresult AndroidMediaReader::ReadMetadata(MediaInfo* aInfo,
   return NS_OK;
 }
 
-nsRefPtr<ShutdownPromise>
-AndroidMediaReader::Shutdown()
+void AndroidMediaReader::Shutdown()
 {
   ResetDecode();
   if (mPlugin) {
@@ -108,7 +107,7 @@ AndroidMediaReader::Shutdown()
     mPlugin = nullptr;
   }
 
-  return MediaDecoderReader::Shutdown();
+  MediaDecoderReader::Shutdown();
 }
 
 // Resets all state related to decoding, emptying all buffers etc.
diff --git a/dom/media/android/AndroidMediaReader.h b/dom/media/android/AndroidMediaReader.h
index 4738cfa7b6a0..90c4c929abe4 100644
--- a/dom/media/android/AndroidMediaReader.h
+++ b/dom/media/android/AndroidMediaReader.h
@@ -71,7 +71,7 @@ public:
                                 MetadataTags** aTags);
   virtual void Seek(int64_t aTime, int64_t aStartTime, int64_t aEndTime, int64_t aCurrentTime);
 
-  virtual nsRefPtr<ShutdownPromise> Shutdown() MOZ_OVERRIDE;
+  virtual void Shutdown() MOZ_OVERRIDE;
 
   class ImageBufferCallback : public MPAPI::BufferCallback {
     typedef mozilla::layers::Image Image;
diff --git a/dom/media/fmp4/MP4Reader.cpp b/dom/media/fmp4/MP4Reader.cpp
index b54a8b80ebac..0482ae5400ac 100644
--- a/dom/media/fmp4/MP4Reader.cpp
+++ b/dom/media/fmp4/MP4Reader.cpp
@@ -139,7 +139,7 @@ MP4Reader::~MP4Reader()
   MOZ_COUNT_DTOR(MP4Reader);
 }
 
-nsRefPtr<ShutdownPromise>
+void
 MP4Reader::Shutdown()
 {
   MOZ_ASSERT(GetTaskQueue()->IsCurrentThreadIn());
@@ -172,7 +172,7 @@ MP4Reader::Shutdown()
     mPlatform = nullptr;
   }
 
-  return MediaDecoderReader::Shutdown();
+  MediaDecoderReader::Shutdown();
 }
 
 void
diff --git a/dom/media/fmp4/MP4Reader.h b/dom/media/fmp4/MP4Reader.h
index bead54a72c50..0c425a98fad4 100644
--- a/dom/media/fmp4/MP4Reader.h
+++ b/dom/media/fmp4/MP4Reader.h
@@ -71,7 +71,7 @@ public:
 
   virtual nsresult ResetDecode() MOZ_OVERRIDE;
 
-  virtual nsRefPtr<ShutdownPromise> Shutdown() MOZ_OVERRIDE;
+  virtual void Shutdown() MOZ_OVERRIDE;
 
 private:
 
diff --git a/dom/media/mediasource/MediaSourceDecoder.h b/dom/media/mediasource/MediaSourceDecoder.h
index efb61a0caef6..4d1f724e470c 100644
--- a/dom/media/mediasource/MediaSourceDecoder.h
+++ b/dom/media/mediasource/MediaSourceDecoder.h
@@ -11,7 +11,6 @@
 #include "nsCOMPtr.h"
 #include "nsError.h"
 #include "MediaDecoder.h"
-#include "MediaSourceReader.h"
 
 class nsIStreamListener;
 
@@ -19,6 +18,7 @@ namespace mozilla {
 
 class MediaResource;
 class MediaDecoderStateMachine;
+class MediaSourceReader;
 class SourceBufferDecoder;
 class TrackBuffer;
 
@@ -71,8 +71,6 @@ public:
   virtual nsresult SetCDMProxy(CDMProxy* aProxy) MOZ_OVERRIDE;
 #endif
 
-  MediaSourceReader* GetReader() { return mReader; }
-
 private:
   // The owning MediaSource holds a strong reference to this decoder, and
   // calls Attach/DetachMediaSource on this decoder to set and clear
diff --git a/dom/media/mediasource/MediaSourceReader.cpp b/dom/media/mediasource/MediaSourceReader.cpp
index 269794a840ea..d6770e640e4b 100644
--- a/dom/media/mediasource/MediaSourceReader.cpp
+++ b/dom/media/mediasource/MediaSourceReader.cpp
@@ -236,35 +236,17 @@ MediaSourceReader::OnNotDecoded(MediaData::Type aType, NotDecodedReason aReason)
   GetCallback()->OnNotDecoded(aType, WAITING_FOR_DATA);
 }
 
-nsRefPtr<ShutdownPromise>
+void
 MediaSourceReader::Shutdown()
 {
-  MOZ_ASSERT(mMediaSourceShutdownPromise.IsEmpty());
-  nsRefPtr<ShutdownPromise> p = mMediaSourceShutdownPromise.Ensure(__func__);
-
-  ContinueShutdown(true);
-  return p;
-}
-
-void
-MediaSourceReader::ContinueShutdown(bool aSuccess)
-{
-  MOZ_ASSERT(aSuccess);
-  if (mTrackBuffers.Length()) {
-    mTrackBuffers[0]->Shutdown()->Then(GetTaskQueue(), __func__, this,
-                                       &MediaSourceReader::ContinueShutdown,
-                                       &MediaSourceReader::ContinueShutdown);
-    mShutdownTrackBuffers.AppendElement(mTrackBuffers[0]);
-    mTrackBuffers.RemoveElementAt(0);
-    return;
+  MediaDecoderReader::Shutdown();
+  for (uint32_t i = 0; i < mTrackBuffers.Length(); ++i) {
+    mTrackBuffers[i]->Shutdown();
   }
-
   mAudioTrack = nullptr;
   mAudioReader = nullptr;
   mVideoTrack = nullptr;
   mVideoReader = nullptr;
-
-  MediaDecoderReader::Shutdown()->ChainTo(mMediaSourceShutdownPromise.Steal(), __func__);
 }
 
 void
@@ -277,12 +259,11 @@ MediaSourceReader::BreakCycles()
   MOZ_ASSERT(!mAudioReader);
   MOZ_ASSERT(!mVideoTrack);
   MOZ_ASSERT(!mVideoReader);
-  MOZ_ASSERT(!mTrackBuffers.Length());
 
-  for (uint32_t i = 0; i < mShutdownTrackBuffers.Length(); ++i) {
-    mShutdownTrackBuffers[i]->BreakCycles();
+  for (uint32_t i = 0; i < mTrackBuffers.Length(); ++i) {
+    mTrackBuffers[i]->BreakCycles();
   }
-  mShutdownTrackBuffers.Clear();
+  mTrackBuffers.Clear();
 }
 
 already_AddRefed<MediaDecoderReader>
diff --git a/dom/media/mediasource/MediaSourceReader.h b/dom/media/mediasource/MediaSourceReader.h
index eabc1e93c7a8..fdeb09b21d36 100644
--- a/dom/media/mediasource/MediaSourceReader.h
+++ b/dom/media/mediasource/MediaSourceReader.h
@@ -97,7 +97,7 @@ public:
   void RemoveTrackBuffer(TrackBuffer* aTrackBuffer);
   void OnTrackBufferConfigured(TrackBuffer* aTrackBuffer, const MediaInfo& aInfo);
 
-  nsRefPtr<ShutdownPromise> Shutdown() MOZ_OVERRIDE;
+  void Shutdown();
 
   virtual void BreakCycles();
 
@@ -135,7 +135,6 @@ private:
   nsRefPtr<MediaDecoderReader> mVideoReader;
 
   nsTArray<nsRefPtr<TrackBuffer>> mTrackBuffers;
-  nsTArray<nsRefPtr<TrackBuffer>> mShutdownTrackBuffers;
   nsTArray<nsRefPtr<TrackBuffer>> mEssentialTrackBuffers;
   nsRefPtr<TrackBuffer> mAudioTrack;
   nsRefPtr<TrackBuffer> mVideoTrack;
@@ -177,9 +176,6 @@ private:
   bool mVideoIsSeeking;
 
   bool mHasEssentialTrackBuffers;
-
-  void ContinueShutdown(bool aSuccess);
-  MediaPromiseHolder<ShutdownPromise> mMediaSourceShutdownPromise;
 #ifdef MOZ_FMP4
   nsRefPtr<SharedDecoderManager> mSharedDecoderManager;
 #endif
diff --git a/dom/media/mediasource/TrackBuffer.cpp b/dom/media/mediasource/TrackBuffer.cpp
index 73a4030e1f9d..e19dcea290e6 100644
--- a/dom/media/mediasource/TrackBuffer.cpp
+++ b/dom/media/mediasource/TrackBuffer.cpp
@@ -96,39 +96,23 @@ private:
   nsAutoTArray<nsRefPtr<SourceBufferDecoder>,2> mDecoders;
 };
 
-nsRefPtr<ShutdownPromise>
+void
 TrackBuffer::Shutdown()
 {
-  MOZ_ASSERT(mShutdownPromise.IsEmpty());
-  nsRefPtr<ShutdownPromise> p = mShutdownPromise.Ensure(__func__);
-
-  RefPtr<MediaTaskQueue> queue = mTaskQueue;
+  // Finish any decoder initialization, which may add to mInitializedDecoders.
+  // Shutdown waits for any pending events, which may require the monitor,
+  // so we must not hold the monitor during this call.
+  mParentDecoder->GetReentrantMonitor().AssertNotCurrentThreadIn();
+  mTaskQueue->BeginShutdown();
+  mTaskQueue->AwaitShutdownAndIdle();
   mTaskQueue = nullptr;
-  queue->BeginShutdown()
-       ->Then(mParentDecoder->GetReader()->GetTaskQueue(), __func__, this,
-              &TrackBuffer::ContinueShutdown, &TrackBuffer::ContinueShutdown);
 
-  return p;
-}
-
-void
-TrackBuffer::ContinueShutdown(bool aSuccess)
-{
-  MOZ_ASSERT(aSuccess);
   ReentrantMonitorAutoEnter mon(mParentDecoder->GetReentrantMonitor());
-  if (mDecoders.Length()) {
-    mDecoders[0]->GetReader()->Shutdown()
-                ->Then(mParentDecoder->GetReader()->GetTaskQueue(), __func__, this,
-                       &TrackBuffer::ContinueShutdown, &TrackBuffer::ContinueShutdown);
-    mShutdownDecoders.AppendElement(mDecoders[0]);
-    mDecoders.RemoveElementAt(0);
-    return;
+  for (uint32_t i = 0; i < mDecoders.Length(); ++i) {
+    mDecoders[i]->GetReader()->Shutdown();
   }
-
   mInitializedDecoders.Clear();
   mParentDecoder = nullptr;
-
-  mShutdownPromise.Resolve(true, __func__);
 }
 
 bool
@@ -449,13 +433,12 @@ TrackBuffer::BreakCycles()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  for (uint32_t i = 0; i < mShutdownDecoders.Length(); ++i) {
-    mShutdownDecoders[i]->BreakCycles();
+  for (uint32_t i = 0; i < mDecoders.Length(); ++i) {
+    mDecoders[i]->BreakCycles();
   }
-  mShutdownDecoders.Clear();
+  mDecoders.Clear();
 
   // These are cleared in Shutdown()
-  MOZ_ASSERT(!mDecoders.Length());
   MOZ_ASSERT(mInitializedDecoders.IsEmpty());
   MOZ_ASSERT(!mParentDecoder);
 }
diff --git a/dom/media/mediasource/TrackBuffer.h b/dom/media/mediasource/TrackBuffer.h
index ef2ee18dd942..0e4770f11818 100644
--- a/dom/media/mediasource/TrackBuffer.h
+++ b/dom/media/mediasource/TrackBuffer.h
@@ -8,7 +8,6 @@
 #define MOZILLA_TRACKBUFFER_H_
 
 #include "SourceBufferDecoder.h"
-#include "MediaPromise.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/mozalloc.h"
@@ -34,7 +33,7 @@ public:
 
   TrackBuffer(MediaSourceDecoder* aParentDecoder, const nsACString& aType);
 
-  nsRefPtr<ShutdownPromise> Shutdown();
+  void Shutdown();
 
   // Append data to the current decoder.  Also responsible for calling
   // NotifyDataArrived on the decoder to keep buffered range computation up
@@ -132,11 +131,6 @@ private:
   // mParentDecoder's monitor.
   nsTArray<nsRefPtr<SourceBufferDecoder>> mDecoders;
 
-  // During shutdown, we move decoders from mDecoders to mShutdownDecoders after
-  // invoking Shutdown. This is all so that we can avoid destroying the decoders
-  // off-main-thread. :-(
-  nsTArray<nsRefPtr<SourceBufferDecoder>> mShutdownDecoders;
-
   // Contains only the initialized decoders managed by this TrackBuffer.
   // Access protected by mParentDecoder's monitor.
   nsTArray<nsRefPtr<SourceBufferDecoder>> mInitializedDecoders;
@@ -159,9 +153,6 @@ private:
   // Set when the first decoder used by this TrackBuffer is initialized.
   // Protected by mParentDecoder's monitor.
   MediaInfo mInfo;
-
-  void ContinueShutdown(bool aSuccess);
-  MediaPromiseHolder<ShutdownPromise> mShutdownPromise;
 };
 
 } // namespace mozilla
diff --git a/dom/media/mediasource/moz.build b/dom/media/mediasource/moz.build
index 4365bc991901..1bf57102a455 100644
--- a/dom/media/mediasource/moz.build
+++ b/dom/media/mediasource/moz.build
@@ -8,7 +8,6 @@ MOCHITEST_MANIFESTS += ['test/mochitest.ini']
 EXPORTS += [
     'AsyncEventRunner.h',
     'MediaSourceDecoder.h',
-    'MediaSourceReader.h',
 ]
 
 EXPORTS.mozilla.dom += [
diff --git a/dom/media/omx/MediaCodecReader.cpp b/dom/media/omx/MediaCodecReader.cpp
index c78b7c19fe17..634a62ab198c 100644
--- a/dom/media/omx/MediaCodecReader.cpp
+++ b/dom/media/omx/MediaCodecReader.cpp
@@ -344,11 +344,11 @@ MediaCodecReader::ReleaseMediaResources()
   ReleaseCriticalResources();
 }
 
-nsRefPtr<ShutdownPromise>
+void
 MediaCodecReader::Shutdown()
 {
   ReleaseResources();
-  return MediaDecoderReader::Shutdown();
+  MediaDecoderReader::Shutdown();
 }
 
 void
diff --git a/dom/media/omx/MediaCodecReader.h b/dom/media/omx/MediaCodecReader.h
index b82531058e41..3f51e34da08e 100644
--- a/dom/media/omx/MediaCodecReader.h
+++ b/dom/media/omx/MediaCodecReader.h
@@ -68,7 +68,7 @@ public:
   // Destroys the decoding state. The reader cannot be made usable again.
   // This is different from ReleaseMediaResources() as Shutdown() is
   // irreversible, whereas ReleaseMediaResources() is reversible.
-  virtual nsRefPtr<ShutdownPromise> Shutdown();
+  virtual void Shutdown();
 
   // Used to retrieve some special information that can only be retrieved after
   // all contents have been continuously parsed. (ex. total duration of some
diff --git a/dom/media/omx/MediaOmxReader.cpp b/dom/media/omx/MediaOmxReader.cpp
index 4d9b69177a70..309d11d4f688 100644
--- a/dom/media/omx/MediaOmxReader.cpp
+++ b/dom/media/omx/MediaOmxReader.cpp
@@ -175,20 +175,17 @@ void MediaOmxReader::ReleaseDecoder()
   mOmxDecoder.clear();
 }
 
-nsRefPtr<ShutdownPromise>
-MediaOmxReader::Shutdown()
+void MediaOmxReader::Shutdown()
 {
   nsCOMPtr<nsIRunnable> cancelEvent =
     NS_NewRunnableMethod(this, &MediaOmxReader::CancelProcessCachedData);
   NS_DispatchToMainThread(cancelEvent);
 
-  nsRefPtr<ShutdownPromise> p = MediaDecoderReader::Shutdown();
+  MediaDecoderReader::Shutdown();
 
   nsCOMPtr<nsIRunnable> event =
     NS_NewRunnableMethod(this, &MediaOmxReader::ReleaseDecoder);
   NS_DispatchToMainThread(event);
-
-  return p;
 }
 
 bool MediaOmxReader::IsWaitingMediaResources()
diff --git a/dom/media/omx/MediaOmxReader.h b/dom/media/omx/MediaOmxReader.h
index cbe88c09c726..0a0d67192351 100644
--- a/dom/media/omx/MediaOmxReader.h
+++ b/dom/media/omx/MediaOmxReader.h
@@ -104,7 +104,7 @@ public:
 
   virtual void SetIdle() MOZ_OVERRIDE;
 
-  virtual nsRefPtr<ShutdownPromise> Shutdown() MOZ_OVERRIDE;
+  virtual void Shutdown() MOZ_OVERRIDE;
 
   bool IsShutdown() {
     MutexAutoLock lock(mMutex);
diff --git a/dom/media/webm/WebMReader.cpp b/dom/media/webm/WebMReader.cpp
index e9c3bdac1eab..5b47c331a1e5 100644
--- a/dom/media/webm/WebMReader.cpp
+++ b/dom/media/webm/WebMReader.cpp
@@ -218,8 +218,7 @@ WebMReader::~WebMReader()
   MOZ_COUNT_DTOR(WebMReader);
 }
 
-nsRefPtr<ShutdownPromise>
-WebMReader::Shutdown()
+void WebMReader::Shutdown()
 {
 #if defined(MOZ_PDM_VPX)
   if (mVideoTaskQueue) {
@@ -233,7 +232,7 @@ WebMReader::Shutdown()
     mVideoDecoder = nullptr;
   }
 
-  return MediaDecoderReader::Shutdown();
+  MediaDecoderReader::Shutdown();
 }
 
 nsresult WebMReader::Init(MediaDecoderReader* aCloneDonor)
diff --git a/dom/media/webm/WebMReader.h b/dom/media/webm/WebMReader.h
index 94b4f5d42d1f..2e19bc8f0b05 100644
--- a/dom/media/webm/WebMReader.h
+++ b/dom/media/webm/WebMReader.h
@@ -133,7 +133,7 @@ protected:
   ~WebMReader();
 
 public:
-  virtual nsRefPtr<ShutdownPromise> Shutdown() MOZ_OVERRIDE;
+  virtual void Shutdown() MOZ_OVERRIDE;
   virtual nsresult Init(MediaDecoderReader* aCloneDonor);
   virtual nsresult ResetDecode();
   virtual bool DecodeAudioData();