--- a/dom/media/CubebUtils.cpp
+++ b/dom/media/CubebUtils.cpp
@@ -420,17 +420,17 @@ Maybe<uint32_t> GetCubebMSGLatencyInFram
 void InitLibrary()
 {
   Preferences::RegisterCallbackAndCall(PrefChanged, PREF_VOLUME_SCALE);
   Preferences::RegisterCallbackAndCall(PrefChanged, PREF_CUBEB_LATENCY_PLAYBACK);
   Preferences::RegisterCallbackAndCall(PrefChanged, PREF_CUBEB_LATENCY_MSG);
   Preferences::RegisterCallbackAndCall(PrefChanged, PREF_CUBEB_BACKEND);
   Preferences::RegisterCallbackAndCall(PrefChanged, PREF_CUBEB_LOG_LEVEL);
 #ifndef MOZ_WIDGET_ANDROID
-  AbstractThread::MainThread()->Dispatch(
+  NS_DispatchToMainThread(
     NS_NewRunnableFunction("CubebUtils::InitLibrary", &InitBrandName));
 #endif
 }
 
 void ShutdownLibrary()
 {
   Preferences::UnregisterCallback(PrefChanged, PREF_VOLUME_SCALE);
   Preferences::UnregisterCallback(PrefChanged, PREF_CUBEB_BACKEND);

--- a/dom/media/DOMMediaStream.cpp
+++ b/dom/media/DOMMediaStream.cpp
@@ -142,19 +142,18 @@ NS_IMPL_CYCLE_COLLECTION_0(MediaStreamTr
 class DOMMediaStream::OwnedStreamListener : public MediaStreamListener {
 public:
   explicit OwnedStreamListener(DOMMediaStream* aStream)
     : mStream(aStream)
   {}
 
   void Forget() { mStream = nullptr; }
 
-  void DoNotifyTrackCreated(MediaStreamGraph* aGraph, TrackID aTrackID,
-                            MediaSegment::Type aType, MediaStream* aInputStream,
-                            TrackID aInputTrackID)
+  void DoNotifyTrackCreated(TrackID aTrackID, MediaSegment::Type aType,
+                            MediaStream* aInputStream, TrackID aInputTrackID)
   {
     MOZ_ASSERT(NS_IsMainThread());
 
     if (!mStream) {
       return;
     }
 
     MediaStreamTrack* track =
@@ -182,72 +181,70 @@ public:
       nsPIDOMWindowInner* window = mStream->GetParentObject();
       nsIDocument* doc = window ? window->GetExtantDoc() : nullptr;
       nsIPrincipal* principal = doc ? doc->NodePrincipal() : nullptr;
       source = new BasicTrackSource(principal);
     }
 
     RefPtr<MediaStreamTrack> newTrack =
       mStream->CreateDOMTrack(aTrackID, aType, source);
-    aGraph->AbstractMainThread()->Dispatch(NewRunnableMethod<RefPtr<MediaStreamTrack>>(
+    NS_DispatchToMainThread(NewRunnableMethod<RefPtr<MediaStreamTrack>>(
       "DOMMediaStream::AddTrackInternal",
       mStream,
       &DOMMediaStream::AddTrackInternal,
       newTrack));
   }
 
-  void DoNotifyTrackEnded(MediaStreamGraph* aGraph, MediaStream* aInputStream,
-                          TrackID aInputTrackID, TrackID aTrackID)
+  void DoNotifyTrackEnded(MediaStream* aInputStream, TrackID aInputTrackID,
+                          TrackID aTrackID)
   {
     MOZ_ASSERT(NS_IsMainThread());
 
     if (!mStream) {
       return;
     }
 
     RefPtr<MediaStreamTrack> track =
       mStream->FindOwnedDOMTrack(aInputStream, aInputTrackID, aTrackID);
     NS_ASSERTION(track, "Owned MediaStreamTracks must be known by the DOMMediaStream");
     if (track) {
       LOG(LogLevel::Debug, ("DOMMediaStream %p MediaStreamTrack %p ended at the source. Marking it ended.",
                             mStream, track.get()));
-      aGraph->AbstractMainThread()->Dispatch(
+      NS_DispatchToMainThread(
         NewRunnableMethod("dom::MediaStreamTrack::OverrideEnded",
                           track,
                           &MediaStreamTrack::OverrideEnded));
     }
   }
 
   void NotifyQueuedTrackChanges(MediaStreamGraph* aGraph, TrackID aID,
                                 StreamTime aTrackOffset, TrackEventCommand aTrackEvents,
                                 const MediaSegment& aQueuedMedia,
                                 MediaStream* aInputStream,
                                 TrackID aInputTrackID) override
   {
     if (aTrackEvents & TrackEventCommand::TRACK_EVENT_CREATED) {
       aGraph->DispatchToMainThreadAfterStreamStateUpdate(
-        NewRunnableMethod<MediaStreamGraph*, TrackID,
+        NewRunnableMethod<TrackID,
                           MediaSegment::Type,
                           RefPtr<MediaStream>,
                           TrackID>(
           "DOMMediaStream::OwnedStreamListener::DoNotifyTrackCreated",
           this,
           &OwnedStreamListener::DoNotifyTrackCreated,
-          aGraph,
           aID,
           aQueuedMedia.GetType(),
           aInputStream,
           aInputTrackID));
     } else if (aTrackEvents & TrackEventCommand::TRACK_EVENT_ENDED) {
       aGraph->DispatchToMainThreadAfterStreamStateUpdate(
-        NewRunnableMethod<MediaStreamGraph*, RefPtr<MediaStream>, TrackID, TrackID>(
+        NewRunnableMethod<RefPtr<MediaStream>, TrackID, TrackID>(
           "DOMMediaStream::OwnedStreamListener::DoNotifyTrackEnded",
           this,
           &OwnedStreamListener::DoNotifyTrackEnded,
-          aGraph,
           aInputStream,
           aInputTrackID,
           aID));
     }
   }
 
 private:
   // These fields may only be accessed on the main thread
@@ -277,35 +274,33 @@ public:
 
     if (!mStream) {
       return;
     }
 
     // The owned stream listener adds its tracks after another main thread
     // dispatch. We have to do the same to notify of created tracks to stay
     // in sync. (Or NotifyTracksCreated is called before tracks are added).
-    MOZ_ASSERT(mStream->GetPlaybackStream());
-    mStream->GetPlaybackStream()->Graph()->AbstractMainThread()->Dispatch(
+    NS_DispatchToMainThread(
       NewRunnableMethod("DOMMediaStream::NotifyTracksCreated",
                         mStream,
                         &DOMMediaStream::NotifyTracksCreated));
   }
 
   void DoNotifyFinished()
   {
     MOZ_ASSERT(NS_IsMainThread());
 
     if (!mStream) {
       return;
     }
 
-    mStream->GetPlaybackStream()->Graph()->AbstractMainThread()->Dispatch(
-        NewRunnableMethod("DOMMediaStream::NotifyFinished",
-                          mStream,
-                          &DOMMediaStream::NotifyFinished));
+    NS_DispatchToMainThread(NewRunnableMethod("DOMMediaStream::NotifyFinished",
+                                              mStream,
+                                              &DOMMediaStream::NotifyFinished));
   }
 
   // The methods below are called on the MediaStreamGraph thread.
 
   void NotifyFinishedTrackCreation(MediaStreamGraph* aGraph) override
   {
     aGraph->DispatchToMainThreadAfterStreamStateUpdate(
       NewRunnableMethod(

--- a/dom/media/GraphDriver.cpp
+++ b/dom/media/GraphDriver.cpp
@@ -160,20 +160,19 @@ private:
   nsCOMPtr<nsIThread> mThread;
 };
 
 ThreadedDriver::~ThreadedDriver()
 {
   if (mThread) {
     nsCOMPtr<nsIRunnable> event =
       new MediaStreamGraphShutdownThreadRunnable(mThread.forget());
-    GraphImpl()->Dispatch(event.forget());
+    NS_DispatchToMainThread(event);
   }
 }
-
 class MediaStreamGraphInitThreadRunnable : public Runnable {
 public:
   explicit MediaStreamGraphInitThreadRunnable(ThreadedDriver* aDriver)
     : Runnable("MediaStreamGraphInitThreadRunnable")
     , mDriver(aDriver)
   {
   }
   NS_IMETHOD Run() override
@@ -489,21 +488,20 @@ AsyncCubebTask::EnsureThread()
   if (!sThreadPool) {
     nsCOMPtr<nsIThreadPool> threadPool =
       SharedThreadPool::Get(NS_LITERAL_CSTRING("CubebOperation"), 1);
     sThreadPool = threadPool;
     // Need to null this out before xpcom-shutdown-threads Observers run
     // since we don't know the order that the shutdown-threads observers
     // will run.  ClearOnShutdown guarantees it runs first.
     if (!NS_IsMainThread()) {
-      nsCOMPtr<nsIRunnable> runnable =
+      NS_DispatchToMainThread(
         NS_NewRunnableFunction("AsyncCubebTask::EnsureThread", []() -> void {
           ClearOnShutdown(&sThreadPool, ShutdownPhase::ShutdownThreads);
-        });
-      AbstractThread::MainThread()->Dispatch(runnable.forget());
+        }));
     } else {
       ClearOnShutdown(&sThreadPool, ShutdownPhase::ShutdownThreads);
     }
 
     const uint32_t kIdleThreadTimeoutMs = 2000;
 
     nsresult rv = sThreadPool->SetIdleThreadTimeout(PR_MillisecondsToInterval(kIdleThreadTimeoutMs));
     if (NS_WARN_IF(NS_FAILED(rv))) {

--- a/dom/media/webaudio/BiquadFilterNode.cpp
+++ b/dom/media/webaudio/BiquadFilterNode.cpp
@@ -172,18 +172,17 @@ public:
     } else if(mBiquads.Length() != aInput.ChannelCount()){
       if (mBiquads.IsEmpty()) {
         RefPtr<PlayingRefChangeHandler> refchanged =
           new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::ADDREF);
         aStream->Graph()->DispatchToMainThreadAfterStreamStateUpdate(
           refchanged.forget());
       } else { // Help people diagnose bug 924718
         WebAudioUtils::LogToDeveloperConsole(mWindowID,
-                                             "BiquadFilterChannelCountChangeWarning",
-                                             aStream->Graph()->AbstractMainThread());
+                                             "BiquadFilterChannelCountChangeWarning");
       }
 
       // Adjust the number of biquads based on the number of channels
       mBiquads.SetLength(aInput.ChannelCount());
     }
 
     uint32_t numberOfChannels = mBiquads.Length();
     aOutput->AllocateChannels(numberOfChannels);

--- a/dom/media/webaudio/IIRFilterNode.cpp
+++ b/dom/media/webaudio/IIRFilterNode.cpp
@@ -68,18 +68,17 @@ public:
     } else if(mIIRFilters.Length() != aInput.ChannelCount()){
       if (mIIRFilters.IsEmpty()) {
         RefPtr<PlayingRefChangeHandler> refchanged =
           new PlayingRefChangeHandler(aStream, PlayingRefChangeHandler::ADDREF);
         aStream->Graph()->DispatchToMainThreadAfterStreamStateUpdate(
           refchanged.forget());
       } else {
         WebAudioUtils::LogToDeveloperConsole(mWindowID,
-                                             "IIRFilterChannelCountChangeWarning",
-                                             aStream->Graph()->AbstractMainThread());
+                                             "IIRFilterChannelCountChangeWarning");
       }
 
       // Adjust the number of filters based on the number of channels
       mIIRFilters.SetLength(aInput.ChannelCount());
       for (size_t i = 0; i < aInput.ChannelCount(); ++i) {
         mIIRFilters[i] = new blink::IIRFilter(&mFeedforward, &mFeedback);
       }
     }

--- a/dom/media/webaudio/WebAudioUtils.cpp
+++ b/dom/media/webaudio/WebAudioUtils.cpp
@@ -89,28 +89,27 @@ WebAudioUtils::SpeexResamplerProcess(Spe
   ConvertAudioSamples(aIn, tmp1.Elements(), *aInLen);
   int result = speex_resampler_process_float(aResampler, aChannel, tmp1.Elements(), aInLen, tmp2.Elements(), aOutLen);
   ConvertAudioSamples(tmp2.Elements(), aOut, *aOutLen);
   return result;
 #endif
 }
 
 void
-WebAudioUtils::LogToDeveloperConsole(uint64_t aWindowID, const char* aKey,
-                                     AbstractThread* aMainThread)
+WebAudioUtils::LogToDeveloperConsole(uint64_t aWindowID, const char* aKey)
 {
   // This implementation is derived from dom/media/VideoUtils.cpp, but we
   // use a windowID so that the message is delivered to the developer console.
   // It is similar to ContentUtils::ReportToConsole, but also works off main
   // thread.
   if (!NS_IsMainThread()) {
     nsCOMPtr<nsIRunnable> task = NS_NewRunnableFunction(
       "dom::WebAudioUtils::LogToDeveloperConsole",
-      [aWindowID, aKey, aMainThread]() { LogToDeveloperConsole(aWindowID, aKey, aMainThread); });
-    aMainThread->Dispatch(task.forget(), NS_DISPATCH_NORMAL);
+      [aWindowID, aKey]() { LogToDeveloperConsole(aWindowID, aKey); });
+    NS_DispatchToMainThread(task.forget(), NS_DISPATCH_NORMAL);
     return;
   }
 
   nsCOMPtr<nsIConsoleService> console(
     do_GetService("@mozilla.org/consoleservice;1"));
   if (!console) {
     NS_WARNING("Failed to log message to console.");
     return;

--- a/dom/media/webaudio/WebAudioUtils.h
+++ b/dom/media/webaudio/WebAudioUtils.h
@@ -224,18 +224,17 @@ namespace WebAudioUtils {
 
   int
   SpeexResamplerProcess(SpeexResamplerState* aResampler,
                         uint32_t aChannel,
                         const int16_t* aIn, uint32_t* aInLen,
                         int16_t* aOut, uint32_t* aOutLen);
 
   void
-  LogToDeveloperConsole(uint64_t aWindowID, const char* aKey,
-                        AbstractThread* aMainThread);
+  LogToDeveloperConsole(uint64_t aWindowID, const char* aKey);
 
   } // namespace WebAudioUtils
 
 } // namespace dom
 } // namespace mozilla
 
 #endif