Bug 1809753 - Part 4: Remove unnecessary GetMainThreadEventTarget, r=mccr8

This method always returned GetMainThreadSerialEventTarget(). This patch switches all callers over to use that method instead. We can't easily switch all calls to be calls to NS_GetMainThread(), as there is no version of that method returning a bare nsIThread* instance. I didn't introduce one, as we may want to add a lock around mMainThread in the future, which would require removing nsThreadManager::GetMainThreadWeak. As this method only returns nsISerialEventTarget, it method could remain implemented, however, by returning a statically allocated fake event target which forwards dispatches (and QIs to nsIThread) to the real main thread. Differential Revision: https://phabricator.services.mozilla.com/D166608
2023-01-16 23:14:12 +00:00 · 2023-01-16 23:14:12 +00:00 · 9d6bb19c23
--- a/dom/base/ImageEncoder.cpp
+++ b/dom/base/ImageEncoder.cpp
@ -52,7 +52,7 @@ class SurfaceHelper : public Runnable {
  }

  already_AddRefed<gfx::DataSourceSurface> GetDataSurfaceSafe() {
-    nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();
+    nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadSerialEventTarget();
    MOZ_ASSERT(mainTarget);
    SyncRunnable::DispatchToThread(mainTarget, this, false);

@ -90,7 +90,7 @@ class EncodingCompleteEvent final : public DiscardableRunnable {
    if (!NS_IsMainThread() && IsCurrentThreadRunningWorker()) {
      mCreationEventTarget = GetCurrentSerialEventTarget();
    } else {
-      mCreationEventTarget = GetMainThreadEventTarget();
+      mCreationEventTarget = GetMainThreadSerialEventTarget();
    }
  }

--- a/dom/base/InProcessBrowserChildMessageManager.cpp
+++ b/dom/base/InProcessBrowserChildMessageManager.cpp
@ -183,7 +183,7 @@ Nullable<WindowProxyHolder> InProcessBrowserChildMessageManager::GetContent(

 already_AddRefed<nsIEventTarget>
 InProcessBrowserChildMessageManager::GetTabEventTarget() {
-  nsCOMPtr<nsIEventTarget> target = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> target = GetMainThreadSerialEventTarget();
  return target.forget();
 }

--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@ -1977,7 +1977,7 @@ static bool DispatchToEventLoop(void* closure,
  // simply NS_DispatchToMainThread. Failure during shutdown is expected and
  // properly handled by the JS engine.

-  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadSerialEventTarget();
  if (!mainTarget) {
    return false;
  }
--- a/dom/fetch/FetchService.cpp
+++ b/dom/fetch/FetchService.cpp
@ -161,13 +161,13 @@ RefPtr<FetchServicePromises> FetchService::FetchInstance::Fetch() {

  // Create a FetchDriver instance
  mFetchDriver = MakeRefPtr<FetchDriver>(
-      mRequest.clonePtr(),         // Fetch Request
-      mPrincipal,                  // Principal
-      mLoadGroup,                  // LoadGroup
-      GetMainThreadEventTarget(),  // MainThreadEventTarget
-      mCookieJarSettings,          // CookieJarSettings
-      mPerformanceStorage,         // PerformanceStorage
-      false                        // IsTrackingFetch
+      mRequest.clonePtr(),               // Fetch Request
+      mPrincipal,                        // Principal
+      mLoadGroup,                        // LoadGroup
+      GetMainThreadSerialEventTarget(),  // MainThreadEventTarget
+      mCookieJarSettings,                // CookieJarSettings
+      mPerformanceStorage,               // PerformanceStorage
+      false                              // IsTrackingFetch
  );

  // Call FetchDriver::Fetch to start fetching.
--- a/dom/file/MutableBlobStorage.cpp
+++ b/dom/file/MutableBlobStorage.cpp
@ -288,7 +288,7 @@ MutableBlobStorage::MutableBlobStorage(MutableBlobStorageType aType,
  MOZ_ASSERT(NS_IsMainThread());

  if (!mEventTarget) {
-    mEventTarget = GetMainThreadEventTarget();
+    mEventTarget = GetMainThreadSerialEventTarget();
  }

  if (aMaxMemory == 0 && aType == eCouldBeInTemporaryFile) {
--- a/dom/file/MutableBlobStreamListener.cpp
+++ b/dom/file/MutableBlobStreamListener.cpp
@ -23,7 +23,7 @@ MutableBlobStreamListener::MutableBlobStreamListener(
  MOZ_ASSERT(aCallback);

  if (!mEventTarget) {
-    mEventTarget = GetMainThreadEventTarget();
+    mEventTarget = GetMainThreadSerialEventTarget();
  }

  MOZ_ASSERT(mEventTarget);
--- a/dom/geolocation/Geolocation.cpp
+++ b/dom/geolocation/Geolocation.cpp
@ -1017,7 +1017,7 @@ void Geolocation::GetCurrentPosition(PositionCallback& aCallback,
 static nsIEventTarget* MainThreadTarget(Geolocation* geo) {
  nsCOMPtr<nsPIDOMWindowInner> window = do_QueryReferent(geo->GetOwner());
  if (!window) {
-    return GetMainThreadEventTarget();
+    return GetMainThreadSerialEventTarget();
  }
  return nsGlobalWindowInner::Cast(window)->EventTargetFor(
      mozilla::TaskCategory::Other);
--- a/dom/media/VideoUtils.cpp
+++ b/dom/media/VideoUtils.cpp
@ -827,7 +827,7 @@ nsresult SimpleTimer::Init(nsIRunnable* aTask, uint32_t aTimeoutMs,
  if (aTarget) {
    target = aTarget;
  } else {
-    target = GetMainThreadEventTarget();
+    target = GetMainThreadSerialEventTarget();
    if (!target) {
      return NS_ERROR_NOT_AVAILABLE;
    }
--- a/dom/media/eme/MediaKeys.cpp
+++ b/dom/media/eme/MediaKeys.cpp
@ -158,7 +158,7 @@ void MediaKeys::OnInnerWindowDestroy() {
  // Don't call shutdown directly because (at time of writing) mProxy can
  // spin the event loop when it's shutdown. This can change the world state
  // in the middle of window destruction, which we do not want.
-  GetMainThreadEventTarget()->Dispatch(
+  GetMainThreadSerialEventTarget()->Dispatch(
      NewRunnableMethod("MediaKeys::Shutdown", this, &MediaKeys::Shutdown));
 }

--- a/dom/media/gtest/TestCDMStorage.cpp
+++ b/dom/media/gtest/TestCDMStorage.cpp
@ -406,7 +406,7 @@ class CDMStorageTest {
          nsCString failureReason;
          self->mCDM
              ->Init(self->mCallback.get(), false, true,
-                     GetMainThreadEventTarget())
+                     GetMainThreadSerialEventTarget())
              ->Then(
                  thread, __func__,
                  [self, updates = std::move(updates)] {
--- a/dom/media/mediacapabilities/DecoderBenchmark.cpp
+++ b/dom/media/mediacapabilities/DecoderBenchmark.cpp
@ -233,7 +233,7 @@ void DecoderBenchmark::CheckVersion(const nsACString& aDecoderName) {
  }

  DebugOnly<nsresult> rv =
-      GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+      GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
          "DecoderBenchmark::CheckVersion", [name, version]() {
            BenchmarkStorageChild::Instance()->SendCheckVersion(name, version);
          }));
--- a/dom/media/platforms/PDMFactory.cpp
+++ b/dom/media/platforms/PDMFactory.cpp
@ -334,7 +334,7 @@ void PDMFactory::EnsureInit() {
    initalization();
    return;
  }
-  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadSerialEventTarget();
  nsCOMPtr<nsIRunnable> runnable = NS_NewRunnableFunction(
      "PDMFactory::EnsureInit", std::move(initalization));
  SyncRunnable::DispatchToThread(mainTarget, runnable);
--- a/dom/media/platforms/wmf/WMFDecoderModule.cpp
+++ b/dom/media/platforms/wmf/WMFDecoderModule.cpp
@ -253,7 +253,8 @@ bool WMFDecoderModule::CanCreateMFTDecoder(const WMFStreamType& aType) {
    } else {
      nsCOMPtr<nsIRunnable> runnable =
          NS_NewRunnableFunction("WMFDecoderModule::Init", [&]() { Init(); });
-      SyncRunnable::DispatchToThread(GetMainThreadEventTarget(), runnable);
+      SyncRunnable::DispatchToThread(GetMainThreadSerialEventTarget(),
+                                     runnable);
    }
  }

--- a/dom/media/webaudio/blink/HRTFDatabaseLoader.cpp
+++ b/dom/media/webaudio/blink/HRTFDatabaseLoader.cpp
@ -123,7 +123,7 @@ class HRTFDatabaseLoader::ProxyReleaseEvent final : public Runnable {
 };

 void HRTFDatabaseLoader::ProxyRelease() {
-  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadSerialEventTarget();
  if (MOZ_LIKELY(mainTarget)) {
    RefPtr<ProxyReleaseEvent> event = new ProxyReleaseEvent(this);
    DebugOnly<nsresult> rv = mainTarget->Dispatch(event, NS_DISPATCH_NORMAL);
--- a/dom/media/webrtc/jsapi/MediaTransportHandler.cpp
+++ b/dom/media/webrtc/jsapi/MediaTransportHandler.cpp
@ -695,7 +695,7 @@ void MediaTransportHandlerSTS::Destroy() {
  CSFLogDebug(LOGTAG, "%s %p", __func__, this);
  // Our "destruction tour" starts on main, because we need to deregister.
  if (!NS_IsMainThread()) {
-    GetMainThreadEventTarget()->Dispatch(NewNonOwningRunnableMethod(
+    GetMainThreadSerialEventTarget()->Dispatch(NewNonOwningRunnableMethod(
        __func__, this, &MediaTransportHandlerSTS::Destroy));
    return;
  }
--- a/dom/media/webrtc/jsapi/PeerConnectionCtx.cpp
+++ b/dom/media/webrtc/jsapi/PeerConnectionCtx.cpp
@ -532,8 +532,8 @@ static void GMPReady_m() {
 };

 static void GMPReady() {
-  GetMainThreadEventTarget()->Dispatch(WrapRunnableNM(&GMPReady_m),
-                                       NS_DISPATCH_NORMAL);
+  GetMainThreadSerialEventTarget()->Dispatch(WrapRunnableNM(&GMPReady_m),
+                                             NS_DISPATCH_NORMAL);
 };

 void PeerConnectionCtx::initGMP() {
--- a/dom/media/webrtc/jsapi/PeerConnectionImpl.cpp
+++ b/dom/media/webrtc/jsapi/PeerConnectionImpl.cpp
@ -1406,7 +1406,7 @@ void PeerConnectionImpl::UpdateNegotiationNeeded() {
  }

  // Queue a task to run the following steps:
-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__, [this, self = RefPtr<PeerConnectionImpl>(this)] {
        // If connection.[[IsClosed]] is true, abort these steps.
        if (IsClosed()) {
@ -1530,7 +1530,7 @@ PeerConnectionImpl::CreateOffer(const JsepOfferOptions& aOptions) {

  STAMP_TIMECARD(mTimeCard, "Create Offer");

-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__, [this, self = RefPtr<PeerConnectionImpl>(this), aOptions] {
        std::string offer;

@ -1570,7 +1570,7 @@ PeerConnectionImpl::CreateAnswer() {
  // add it as a param to CreateAnswer, and convert it here.
  JsepAnswerOptions options;

-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__, [this, self = RefPtr<PeerConnectionImpl>(this), options] {
        std::string answer;
        SyncToJsep();
@ -1889,7 +1889,7 @@ PeerConnectionImpl::AddIceCandidate(
      mRawTrickledCandidates.push_back(aCandidate);
    }
    // Spec says we queue a task for these updates
-    GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+    GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
        __func__, [this, self = RefPtr<PeerConnectionImpl>(this)] {
          if (IsClosed()) {
            return;
@ -1910,7 +1910,7 @@ PeerConnectionImpl::AddIceCandidate(
                static_cast<unsigned>(*result.mError), aCandidate,
                level.valueOr(-1), errorString.c_str());

-    GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+    GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
        __func__,
        [this, self = RefPtr<PeerConnectionImpl>(this), errorString, result] {
          if (IsClosed()) {
@ -2577,7 +2577,7 @@ already_AddRefed<dom::Promise> PeerConnectionImpl::OnSetDescriptionSuccess(
 void PeerConnectionImpl::DoSetDescriptionSuccessPostProcessing(
    dom::RTCSdpType aSdpType, bool aRemote, const RefPtr<dom::Promise>& aP) {
  // Spec says we queue a task for all the stuff that ends up back in JS
-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__,
      [this, self = RefPtr<PeerConnectionImpl>(this), aSdpType, aRemote, aP] {
        if (IsClosed()) {
@ -3829,7 +3829,7 @@ void PeerConnectionImpl::AddIceCandidate(const std::string& aCandidate,
          cand.mUfrag = aUfrag;
          mQueriedMDNSHostnames[addr].push_back(cand);

-          GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+          GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
              "PeerConnectionImpl::SendQueryMDNSHostname",
              [self = RefPtr<PeerConnectionImpl>(this), addr]() mutable {
                if (self->mStunAddrsRequest) {
@ -4033,7 +4033,7 @@ void PeerConnectionImpl::SignalHandler::IceGatheringStateChange_s(
    dom::RTCIceGatheringState aState) {
  ASSERT_ON_THREAD(mSTSThread);

-  GetMainThreadEventTarget()->Dispatch(
+  GetMainThreadSerialEventTarget()->Dispatch(
      NS_NewRunnableFunction(__func__,
                             [handle = mHandle, aState] {
                               PeerConnectionWrapper wrapper(handle);
@ -4049,7 +4049,7 @@ void PeerConnectionImpl::SignalHandler::IceConnectionStateChange_s(
    dom::RTCIceConnectionState aState) {
  ASSERT_ON_THREAD(mSTSThread);

-  GetMainThreadEventTarget()->Dispatch(
+  GetMainThreadSerialEventTarget()->Dispatch(
      NS_NewRunnableFunction(__func__,
                             [handle = mHandle, aState] {
                               PeerConnectionWrapper wrapper(handle);
@ -4068,7 +4068,7 @@ void PeerConnectionImpl::SignalHandler::OnCandidateFound_s(

  MOZ_ASSERT(!aCandidateInfo.mUfrag.empty());

-  GetMainThreadEventTarget()->Dispatch(
+  GetMainThreadSerialEventTarget()->Dispatch(
      NS_NewRunnableFunction(__func__,
                             [handle = mHandle, aTransportId, aCandidateInfo] {
                               PeerConnectionWrapper wrapper(handle);
@ -4083,7 +4083,7 @@ void PeerConnectionImpl::SignalHandler::OnCandidateFound_s(
 void PeerConnectionImpl::SignalHandler::AlpnNegotiated_s(
    const std::string& aAlpn, bool aPrivacyRequested) {
  MOZ_DIAGNOSTIC_ASSERT((aAlpn == "c-webrtc") == aPrivacyRequested);
-  GetMainThreadEventTarget()->Dispatch(
+  GetMainThreadSerialEventTarget()->Dispatch(
      NS_NewRunnableFunction(__func__,
                             [handle = mHandle, aPrivacyRequested] {
                               PeerConnectionWrapper wrapper(handle);
--- a/dom/media/webrtc/jsapi/RTCRtpSender.cpp
+++ b/dom/media/webrtc/jsapi/RTCRtpSender.cpp
@ -686,7 +686,7 @@ already_AddRefed<Promise> RTCRtpSender::SetParameters(

  // If the media stack is successfully configured with parameters,
  // queue a task to run the following steps:
-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__,
      [this, self = RefPtr<RTCRtpSender>(this), p, paramsCopy, serialNumber] {
        // Set sender.[[LastReturnedParameters]] to null.
@ -853,7 +853,7 @@ void RTCRtpSender::GetParameters(RTCRtpSendParameters& aParameters) {
  mLastReturnedParameters = Some(aParameters);

  // Queue a task that sets sender.[[LastReturnedParameters]] to null.
-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__, [this, self = RefPtr<RTCRtpSender>(this)] {
        mLastReturnedParameters = Nothing();
      }));
@ -1068,7 +1068,7 @@ RefPtr<dom::Promise> ReplaceTrackOperation::CallImpl(ErrorResult& aError) {
  }

  // Queue a task that runs the following steps:
-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      __func__, [p, sender, track = mNewTrack]() MOZ_CAN_RUN_SCRIPT_BOUNDARY {
        // If connection.[[IsClosed]] is true, abort these steps.
        // Set sender.[[SenderTrack]] to withTrack.
--- a/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp
+++ b/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp
@ -254,8 +254,8 @@ void RTCRtpTransceiver::RollbackToStableDtlsTransport() {

 void RTCRtpTransceiver::UpdateDtlsTransportState(
    const std::string& aTransportId, TransportLayer::State aState) {
-  if (!GetMainThreadEventTarget()->IsOnCurrentThread()) {
-    GetMainThreadEventTarget()->Dispatch(
+  if (!GetMainThreadSerialEventTarget()->IsOnCurrentThread()) {
+    GetMainThreadSerialEventTarget()->Dispatch(
        WrapRunnable(this, &RTCRtpTransceiver::UpdateDtlsTransportState,
                     aTransportId, aState),
        NS_DISPATCH_NORMAL);
--- a/dom/media/webrtc/transport/WebrtcTCPSocketWrapper.cpp
+++ b/dom/media/webrtc/transport/WebrtcTCPSocketWrapper.cpp
@ -24,7 +24,7 @@ WebrtcTCPSocketWrapper::WebrtcTCPSocketWrapper(
      mWebrtcTCPSocket(nullptr),
      mMainThread(nullptr),
      mSocketThread(nullptr) {
-  mMainThread = GetMainThreadEventTarget();
+  mMainThread = GetMainThreadSerialEventTarget();
  mSocketThread = do_GetService(NS_SOCKETTRANSPORTSERVICE_CONTRACTID);
  MOZ_RELEASE_ASSERT(mMainThread, "no main thread");
  MOZ_RELEASE_ASSERT(mSocketThread, "no socket thread");
--- a/dom/media/webrtc/transport/ipc/WebrtcTCPSocket.cpp
+++ b/dom/media/webrtc/transport/ipc/WebrtcTCPSocket.cpp
@ -58,7 +58,7 @@ WebrtcTCPSocket::WebrtcTCPSocket(WebrtcTCPSocketCallback* aCallbacks)
      mSocketIn(nullptr),
      mSocketOut(nullptr) {
  LOG(("WebrtcTCPSocket::WebrtcTCPSocket %p\n", this));
-  mMainThread = GetMainThreadEventTarget();
+  mMainThread = GetMainThreadSerialEventTarget();
  mSocketThread = do_GetService(NS_SOCKETTRANSPORTSERVICE_CONTRACTID);
  MOZ_RELEASE_ASSERT(mMainThread, "no main thread");
  MOZ_RELEASE_ASSERT(mSocketThread, "no socket thread");
--- a/dom/media/webrtc/transportbridge/MediaPipeline.cpp
+++ b/dom/media/webrtc/transportbridge/MediaPipeline.cpp
@ -1201,7 +1201,7 @@ class GenericReceiveListener : public MediaTrackListener {
  void OnRtpReceived() {
    if (mMaybeTrackNeedsUnmute) {
      mMaybeTrackNeedsUnmute = false;
-      GetMainThreadEventTarget()->Dispatch(
+      GetMainThreadSerialEventTarget()->Dispatch(
          NewRunnableMethod("GenericReceiveListener::OnRtpReceived_m", this,
                            &GenericReceiveListener::OnRtpReceived_m));
    }
@ -1224,7 +1224,7 @@ class GenericReceiveListener : public MediaTrackListener {
      mSource->Destroy();
    }

-    GetMainThreadEventTarget()->Dispatch(
+    GetMainThreadSerialEventTarget()->Dispatch(
        NewRunnableMethod("RemoteTrackSource::ForceEnded", mTrackSource.get(),
                          &RemoteTrackSource::ForceEnded));
  }
@ -1288,7 +1288,7 @@ class MediaPipelineReceiveAudio::PipelineListener
  void MakePrincipalPrivate_s() {
    mForceSilence = true;

-    GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+    GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
        "MediaPipelineReceiveAudio::PipelineListener::MakePrincipalPrivate_s",
        [self = RefPtr<PipelineListener>(this), this] {
          class Message : public ControlMessage {
@ -1494,7 +1494,7 @@ class MediaPipelineReceiveVideo::PipelineListener
      mForceDropFrames = true;
    }

-    GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+    GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
        __func__, [self = RefPtr<PipelineListener>(this), this] {
          RefPtr<nsIPrincipal> privatePrincipal =
              NullPrincipal::CreateWithInheritedAttributes(
--- a/dom/media/webvtt/TextTrackList.cpp
+++ b/dom/media/webvtt/TextTrackList.cpp
@ -139,7 +139,7 @@ void TextTrackList::CreateAndDispatchChangeEvent() {
 void TextTrackList::CreateAndDispatchTrackEventRunner(
    TextTrack* aTrack, const nsAString& aEventName) {
  DebugOnly<nsresult> rv;
-  nsCOMPtr<nsIEventTarget> target = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> target = GetMainThreadSerialEventTarget();
  if (!target) {
    // If we are not able to get the main-thread object we are shutting down.
    return;
--- a/dom/notification/Notification.cpp
+++ b/dom/notification/Notification.cpp
@ -2322,7 +2322,7 @@ nsresult Notification::DispatchToMainThread(
                              nsIEventTarget::DISPATCH_NORMAL);
    }
  }
-  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadSerialEventTarget();
  MOZ_ASSERT(mainTarget);
  return mainTarget->Dispatch(std::move(aRunnable),
                              nsIEventTarget::DISPATCH_NORMAL);
--- a/dom/webauthn/AndroidWebAuthnTokenManager.cpp
+++ b/dom/webauthn/AndroidWebAuthnTokenManager.cpp
@ -93,7 +93,7 @@ RefPtr<U2FRegisterPromise> AndroidWebAuthnTokenManager::Register(

  ClearPromises();

-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      "java::WebAuthnTokenManager::WebAuthnMakeCredential",
      [self = RefPtr{this}, aInfo, aForceNoneAttestation]() {
        AssertIsOnMainThread();
@ -282,7 +282,7 @@ RefPtr<U2FSignPromise> AndroidWebAuthnTokenManager::Sign(

  ClearPromises();

-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      "java::WebAuthnTokenManager::WebAuthnGetAssertion",
      [self = RefPtr{this}, aInfo]() {
        AssertIsOnMainThread();
--- a/dom/webauthn/U2FSoftTokenManager.cpp
+++ b/dom/webauthn/U2FSoftTokenManager.cpp
@ -195,7 +195,7 @@ nsresult U2FSoftTokenManager::GetOrCreateWrappingKey(
  MOZ_LOG(gNSSTokenLog, LogLevel::Debug,
          ("Key stored, nickname set to %s.", mSecretNickname.get()));

-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      "dom::U2FSoftTokenManager::GetOrCreateWrappingKey", []() {
        MOZ_ASSERT(NS_IsMainThread());
        Preferences::SetUint(PREF_U2F_NSSTOKEN_COUNTER, 0);
@ -885,7 +885,7 @@ RefPtr<U2FSignPromise> U2FSoftTokenManager::Sign(
  counterItem.data[2] = (mCounter >> 8) & 0xFF;
  counterItem.data[3] = (mCounter >> 0) & 0xFF;
  uint32_t counter = mCounter;
-  GetMainThreadEventTarget()->Dispatch(
+  GetMainThreadSerialEventTarget()->Dispatch(
      NS_NewRunnableFunction("dom::U2FSoftTokenManager::Sign", [counter]() {
        MOZ_ASSERT(NS_IsMainThread());
        Preferences::SetUint(PREF_U2F_NSSTOKEN_COUNTER, counter);
--- a/dom/webauthn/U2FTokenManager.cpp
+++ b/dom/webauthn/U2FTokenManager.cpp
@ -273,8 +273,8 @@ void U2FTokenManager::SendPromptNotification(const char16_t* aFormat,
      "U2FTokenManager::RunSendPromptNotification", this,
      &U2FTokenManager::RunSendPromptNotification, json));

-  MOZ_ALWAYS_SUCCEEDS(
-      GetMainThreadEventTarget()->Dispatch(r.forget(), NS_DISPATCH_NORMAL));
+  MOZ_ALWAYS_SUCCEEDS(GetMainThreadSerialEventTarget()->Dispatch(
+      r.forget(), NS_DISPATCH_NORMAL));
 }

 void U2FTokenManager::RunSendPromptNotification(const nsString& aJSON) {
@ -390,8 +390,8 @@ static void status_callback(rust_ctap2_status_update_res* status) {
    nsCOMPtr<nsIRunnable> r(NewRunnableMethod<nsString>(
        "U2FTokenManager::RunSendPromptNotification", gInstance,
        &U2FTokenManager::RunSendPromptNotification, notification_json));
-    MOZ_ALWAYS_SUCCEEDS(
-        GetMainThreadEventTarget()->Dispatch(r.forget(), NS_DISPATCH_NORMAL));
+    MOZ_ALWAYS_SUCCEEDS(GetMainThreadSerialEventTarget()->Dispatch(
+        r.forget(), NS_DISPATCH_NORMAL));
  }
 }

--- a/dom/websocket/WebSocket.cpp
+++ b/dom/websocket/WebSocket.cpp
@ -2755,7 +2755,7 @@ WebSocketImpl::Dispatch(already_AddRefed<nsIRunnable> aEvent, uint32_t aFlags) {
  if (mIsMainThread) {
    return mMainThreadEventTarget
               ? mMainThreadEventTarget->Dispatch(event_ref.forget())
-               : GetMainThreadEventTarget()->Dispatch(event_ref.forget());
+               : GetMainThreadSerialEventTarget()->Dispatch(event_ref.forget());
  }

  MutexAutoLock lock(mMutex);
--- a/dom/workers/RuntimeService.cpp
+++ b/dom/workers/RuntimeService.cpp
@ -2133,7 +2133,7 @@ WorkerThreadPrimaryRunnable::Run() {
  mWorkerPrivate = nullptr;

  // Now recycle this thread.
-  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> mainTarget = GetMainThreadSerialEventTarget();
  MOZ_ASSERT(mainTarget);

  RefPtr<FinishedRunnable> finishedRunnable =
--- a/gfx/layers/ipc/CanvasTranslator.cpp
+++ b/gfx/layers/ipc/CanvasTranslator.cpp
@ -405,7 +405,7 @@ bool CanvasTranslator::CheckForFreshCanvasDevice(int aLineNumber) {

  // It is safe to wait here because only the Compositor thread waits on us and
  // the main thread doesn't wait on the compositor thread in the GPU process.
-  SyncRunnable::DispatchToThread(GetMainThreadEventTarget(), runnable,
+  SyncRunnable::DispatchToThread(GetMainThreadSerialEventTarget(), runnable,
                                 /*aForceDispatch*/ true);

  mDevice = gfx::DeviceManagerDx::Get()->GetCanvasDevice();
--- a/layout/style/nsFontFaceLoader.cpp
+++ b/layout/style/nsFontFaceLoader.cpp
@ -105,7 +105,7 @@ void nsFontFaceLoader::StartedLoading(nsIStreamLoader* aStreamLoader) {
    if (doc) {
      target = doc->EventTargetFor(TaskCategory::Other);
    } else {
-      target = GetMainThreadEventTarget();
+      target = GetMainThreadSerialEventTarget();
    }
    NS_NewTimerWithFuncCallback(
        getter_AddRefs(mLoadTimer), LoadTimerCallback, static_cast<void*>(this),
--- a/media/webrtc/signaling/gtest/mediapipeline_unittest.cpp
+++ b/media/webrtc/signaling/gtest/mediapipeline_unittest.cpp
@ -43,7 +43,7 @@ class MainAsCurrent : public TaskQueueWrapper<DeletionPolicy::NonBlocking> {
 public:
  MainAsCurrent()
      : TaskQueueWrapper(
-            TaskQueue::Create(do_AddRef(GetMainThreadEventTarget()),
+            TaskQueue::Create(do_AddRef(GetMainThreadSerialEventTarget()),
                              "MainAsCurrentTaskQueue"),
            "MainAsCurrent"_ns),
        mSetter(this) {
--- a/netwerk/base/nsAsyncRedirectVerifyHelper.cpp
+++ b/netwerk/base/nsAsyncRedirectVerifyHelper.cpp
@ -81,7 +81,7 @@ nsresult nsAsyncRedirectVerifyHelper::Init(
  nsresult rv;
  rv = mainThreadEventTarget
           ? mainThreadEventTarget->Dispatch(runnable.forget())
-           : GetMainThreadEventTarget()->Dispatch(runnable.forget());
+           : GetMainThreadSerialEventTarget()->Dispatch(runnable.forget());
  NS_ENSURE_SUCCESS(rv, rv);

  if (synchronize) {
--- a/netwerk/base/nsInputStreamPump.cpp
+++ b/netwerk/base/nsInputStreamPump.cpp
@ -100,8 +100,9 @@ nsresult nsInputStreamPump::EnsureWaiting() {
    // created on main thread.
    if (mState == STATE_STOP && !mOffMainThread) {
      nsCOMPtr<nsIEventTarget> mainThread =
-          mLabeledMainThreadTarget ? mLabeledMainThreadTarget
-                                   : do_AddRef(GetMainThreadEventTarget());
+          mLabeledMainThreadTarget
+              ? mLabeledMainThreadTarget
+              : do_AddRef(GetMainThreadSerialEventTarget());
      if (mTargetThread != mainThread) {
        mTargetThread = mainThread;
      }
--- a/netwerk/base/nsRequestObserverProxy.cpp
+++ b/netwerk/base/nsRequestObserverProxy.cpp
@ -167,7 +167,7 @@ nsRequestObserverProxy::Init(nsIRequestObserver* observer,
 //-----------------------------------------------------------------------------

 nsresult nsRequestObserverProxy::FireEvent(nsARequestObserverEvent* event) {
-  nsCOMPtr<nsIEventTarget> mainThread(GetMainThreadEventTarget());
+  nsCOMPtr<nsIEventTarget> mainThread(GetMainThreadSerialEventTarget());
  return mainThread->Dispatch(event, NS_DISPATCH_NORMAL);
 }

--- a/netwerk/cache2/CacheFile.cpp
+++ b/netwerk/cache2/CacheFile.cpp
@ -28,7 +28,7 @@
 //  - CacheFile is still waiting for the handle
 //  - the chunk is preloaded

-//#define CACHE_CHUNKS
+// #define CACHE_CHUNKS

 namespace mozilla::net {

@ -2189,7 +2189,7 @@ void CacheFile::QueueChunkListener(uint32_t aIndex,
    LOG(
        ("CacheFile::QueueChunkListener() - Cannot get Cache I/O thread! Using "
         "main thread for callback."));
-    item->mTarget = GetMainThreadEventTarget();
+    item->mTarget = GetMainThreadSerialEventTarget();
  }
  item->mCallback = aCallback;

--- a/netwerk/cache2/CacheFileChunk.cpp
+++ b/netwerk/cache2/CacheFileChunk.cpp
@ -432,7 +432,7 @@ void CacheFileChunk::WaitForUpdate(CacheFileChunkListener* aCallback) {
    LOG(
        ("CacheFileChunk::WaitForUpdate() - Cannot get Cache I/O thread! Using "
         "main thread for callback."));
-    item->mTarget = GetMainThreadEventTarget();
+    item->mTarget = GetMainThreadSerialEventTarget();
  }
  item->mCallback = aCallback;
  MOZ_ASSERT(item->mTarget);
--- a/netwerk/cache2/CacheFileInputStream.cpp
+++ b/netwerk/cache2/CacheFileInputStream.cpp
@ -635,7 +635,7 @@ void CacheFileInputStream::NotifyListener() {
      LOG(
          ("CacheFileInputStream::NotifyListener() - Cannot get Cache I/O "
           "thread! Using main thread for callback."));
-      mCallbackTarget = GetMainThreadEventTarget();
+      mCallbackTarget = GetMainThreadSerialEventTarget();
    }
  }

--- a/netwerk/cache2/CacheFileOutputStream.cpp
+++ b/netwerk/cache2/CacheFileOutputStream.cpp
@ -440,7 +440,7 @@ void CacheFileOutputStream::NotifyListener() {
      LOG(
          ("CacheFileOutputStream::NotifyListener() - Cannot get Cache I/O "
           "thread! Using main thread for callback."));
-      mCallbackTarget = GetMainThreadEventTarget();
+      mCallbackTarget = GetMainThreadSerialEventTarget();
    }
  }

--- a/netwerk/cache2/CacheStorageService.h
+++ b/netwerk/cache2/CacheStorageService.h
@ -429,7 +429,7 @@ void ProxyRelease(const char* aName, nsCOMPtr<T>& object,

 template <class T>
 void ProxyReleaseMainThread(const char* aName, nsCOMPtr<T>& object) {
-  ProxyRelease(aName, object, GetMainThreadEventTarget());
+  ProxyRelease(aName, object, GetMainThreadSerialEventTarget());
 }

 }  // namespace net
--- a/netwerk/dns/DNSRequestParent.cpp
+++ b/netwerk/dns/DNSRequestParent.cpp
@ -45,7 +45,7 @@ void DNSRequestHandler::DoAsyncResolve(const nsACString& hostname,
  mFlags = flags;
  nsCOMPtr<nsIDNSService> dns = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
  if (NS_SUCCEEDED(rv)) {
-    nsCOMPtr<nsIEventTarget> main = GetMainThreadEventTarget();
+    nsCOMPtr<nsIEventTarget> main = GetMainThreadSerialEventTarget();
    nsCOMPtr<nsICancelable> unused;
    RefPtr<DNSAdditionalInfo> info;
    if (!trrServer.IsEmpty() || port != -1) {
--- a/netwerk/dns/DNSUtils.cpp
+++ b/netwerk/dns/DNSUtils.cpp
@ -54,7 +54,7 @@ nsresult DNSUtils::CreateChannelHelper(nsIURI* aUri, nsIChannel** aResult) {

  // Unfortunately, we can only initialize gHttpHandler on main thread.
  if (!gHttpHandler) {
-    nsCOMPtr<nsIEventTarget> main = GetMainThreadEventTarget();
+    nsCOMPtr<nsIEventTarget> main = GetMainThreadSerialEventTarget();
    if (main) {
      // Forward to the main thread synchronously.
      SyncRunnable::DispatchToThread(
--- a/netwerk/dns/nsDNSService2.cpp
+++ b/netwerk/dns/nsDNSService2.cpp
@ -1039,7 +1039,7 @@ nsresult nsDNSService::AsyncResolveInternal(
  // make sure JS callers get notification on the main thread
  nsCOMPtr<nsIXPConnectWrappedJS> wrappedListener = do_QueryInterface(listener);
  if (wrappedListener && !target) {
-    target = GetMainThreadEventTarget();
+    target = GetMainThreadSerialEventTarget();
  }

  if (target) {
--- a/netwerk/ipc/ChannelEventQueue.h
+++ b/netwerk/ipc/ChannelEventQueue.h
@ -40,7 +40,7 @@ class MainThreadChannelEvent : public ChannelEvent {
  already_AddRefed<nsIEventTarget> GetEventTarget() override {
    MOZ_ASSERT(XRE_IsParentProcess());

-    return do_AddRef(GetMainThreadEventTarget());
+    return do_AddRef(GetMainThreadSerialEventTarget());
  }
 };

--- a/netwerk/ipc/DocumentChannelChild.cpp
+++ b/netwerk/ipc/DocumentChannelChild.cpp
@ -350,8 +350,9 @@ IPCResult DocumentChannelChild::RecvRedirectToRealChannel(
  mRedirectChannel = newChannel;
  mStreamFilterEndpoints = std::move(aEndpoints);

-  rv = gHttpHandler->AsyncOnChannelRedirect(
-      this, newChannel, aArgs.redirectFlags(), GetMainThreadEventTarget());
+  rv = gHttpHandler->AsyncOnChannelRedirect(this, newChannel,
+                                            aArgs.redirectFlags(),
+                                            GetMainThreadSerialEventTarget());

  if (NS_SUCCEEDED(rv)) {
    scopeExit.release();
--- a/netwerk/protocol/http/AltDataOutputStreamChild.cpp
+++ b/netwerk/protocol/http/AltDataOutputStreamChild.cpp
@ -180,7 +180,7 @@ void AltDataOutputStreamChild::NotifyListener() {
  MOZ_ASSERT(mCallback);

  if (!mCallbackTarget) {
-    mCallbackTarget = GetMainThreadEventTarget();
+    mCallbackTarget = GetMainThreadSerialEventTarget();
  }

  nsCOMPtr<nsIOutputStreamCallback> asyncCallback =
--- a/netwerk/protocol/http/AlternateServices.cpp
+++ b/netwerk/protocol/http/AlternateServices.cpp
@ -892,7 +892,7 @@ void AltSvcCache::EnsureStorageInited() {
    return;
  }

-  nsCOMPtr<nsIEventTarget> main = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> main = GetMainThreadSerialEventTarget();
  if (!main) {
    return;
  }
--- a/netwerk/protocol/http/HttpChannelChild.cpp
+++ b/netwerk/protocol/http/HttpChannelChild.cpp
@ -2125,7 +2125,7 @@ already_AddRefed<nsIEventTarget> HttpChannelChild::GetODATarget() {
  }

  if (!target) {
-    target = GetMainThreadEventTarget();
+    target = GetMainThreadSerialEventTarget();
  }
  return target.forget();
 }
--- a/netwerk/protocol/http/HttpTransactionParent.cpp
+++ b/netwerk/protocol/http/HttpTransactionParent.cpp
@ -220,7 +220,7 @@ already_AddRefed<nsIEventTarget> HttpTransactionParent::GetODATarget() {
  }

  if (!target) {
-    target = GetMainThreadEventTarget();
+    target = GetMainThreadSerialEventTarget();
  }
  return target.forget();
 }
@ -400,7 +400,7 @@ already_AddRefed<nsHttpConnectionInfo> HttpTransactionParent::GetConnInfo()
 }

 already_AddRefed<nsIEventTarget> HttpTransactionParent::GetNeckoTarget() {
-  nsCOMPtr<nsIEventTarget> target = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> target = GetMainThreadSerialEventTarget();
  return target.forget();
 }

--- a/netwerk/protocol/http/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/nsHttpChannel.cpp
@ -7971,7 +7971,7 @@ nsHttpChannel::RetargetDeliveryTo(nsIEventTarget* aNewTarget) {

    // If retarget fails for transaction pump, we must restore mCachePump.
    if (NS_FAILED(rv) && retargetableCachePump) {
-      nsCOMPtr<nsIEventTarget> main = GetMainThreadEventTarget();
+      nsCOMPtr<nsIEventTarget> main = GetMainThreadSerialEventTarget();
      NS_ENSURE_TRUE(main, NS_ERROR_UNEXPECTED);
      rv = retargetableCachePump->RetargetDeliveryTo(main);
    }
--- a/netwerk/protocol/websocket/WebSocketChannel.cpp
+++ b/netwerk/protocol/websocket/WebSocketChannel.cpp
@ -2853,7 +2853,7 @@ nsresult WebSocketChannel::DoAdmissionDNS() {
  if (mPort == -1) mPort = (mEncrypted ? kDefaultWSSPort : kDefaultWSPort);
  nsCOMPtr<nsIDNSService> dns = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);
-  nsCOMPtr<nsIEventTarget> main = GetMainThreadEventTarget();
+  nsCOMPtr<nsIEventTarget> main = GetMainThreadSerialEventTarget();
  nsCOMPtr<nsICancelable> cancelable;
  rv = dns->AsyncResolveNative(hostName, nsIDNSService::RESOLVE_TYPE_DEFAULT,
                               nsIDNSService::RESOLVE_DEFAULT_FLAGS, nullptr,
@ -3405,7 +3405,7 @@ WebSocketChannel::AsyncOpenNative(nsIURI* aURI, const nsACString& aOrigin,
  {
    auto lock = mTargetThread.Lock();
    if (!lock.ref()) {
-      lock.ref() = GetMainThreadEventTarget();
+      lock.ref() = GetMainThreadSerialEventTarget();
    }
  }

--- a/netwerk/protocol/websocket/WebSocketChannelChild.cpp
+++ b/netwerk/protocol/websocket/WebSocketChannelChild.cpp
@ -169,7 +169,7 @@ class EventTargetDispatcher : public ChannelEvent {
  already_AddRefed<nsIEventTarget> GetEventTarget() override {
    nsCOMPtr<nsIEventTarget> target = mEventTarget;
    if (!target) {
-      target = GetMainThreadEventTarget();
+      target = GetMainThreadSerialEventTarget();
    }
    return target.forget();
  }
--- a/netwerk/sctp/datachannel/DataChannel.cpp
+++ b/netwerk/sctp/datachannel/DataChannel.cpp
@ -410,7 +410,7 @@ void DataChannelConnection::DestroyOnSTS(struct socket* aMasterSocket,

  disconnect_all();
  mTransportHandler = nullptr;
-  GetMainThreadEventTarget()->Dispatch(NS_NewRunnableFunction(
+  GetMainThreadSerialEventTarget()->Dispatch(NS_NewRunnableFunction(
      "DataChannelConnection::Destroy",
      [id = mId]() { DataChannelRegistry::Deregister(id); }));
 }
--- a/netwerk/wifi/nsWifiMonitor.cpp
+++ b/netwerk/wifi/nsWifiMonitor.cpp
@ -179,7 +179,7 @@ NS_IMETHODIMP nsWifiMonitor::Run() {
  }

  if (doError) {
-    nsCOMPtr<nsIEventTarget> target = GetMainThreadEventTarget();
+    nsCOMPtr<nsIEventTarget> target = GetMainThreadSerialEventTarget();
    if (!target) return NS_ERROR_UNEXPECTED;

    nsCOMPtr<nsIRunnable> runnable(
--- a/security/sandbox/common/test/SandboxTestingParent.cpp
+++ b/security/sandbox/common/test/SandboxTestingParent.cpp
@ -118,7 +118,7 @@ mozilla::ipc::IPCResult SandboxTestingParent::RecvGetSpecialDirectory(
          dir->GetPath(*aDirPath);
        }
      });
-  SyncRunnable::DispatchToThread(GetMainThreadEventTarget(), runnable,
+  SyncRunnable::DispatchToThread(GetMainThreadSerialEventTarget(), runnable,
                                 /*aForceDispatch*/ true);
  return IPC_OK();
 }
--- a/toolkit/components/statusfilter/nsBrowserStatusFilter.cpp
+++ b/toolkit/components/statusfilter/nsBrowserStatusFilter.cpp
@ -15,7 +15,7 @@ using namespace mozilla;
 //-----------------------------------------------------------------------------

 nsBrowserStatusFilter::nsBrowserStatusFilter()
-    : mTarget(GetMainThreadEventTarget()),
+    : mTarget(GetMainThreadSerialEventTarget()),
      mCurProgress(0),
      mMaxProgress(0),
      mCurrentPercentage(0),
--- a/tools/fuzzing/ipc/IPCFuzzController.cpp
+++ b/tools/fuzzing/ipc/IPCFuzzController.cpp
@ -33,13 +33,13 @@ using namespace mozilla::ipc;
 // IPC between other processes will interfere with our fuzzing in the meantime
 // but blocking could also cause hangs when such IPC is required during the
 // fuzzing runtime for some reason.
-//#define MOZ_FUZZ_IPC_SYNC_INJECT 1
+// #define MOZ_FUZZ_IPC_SYNC_INJECT 1

 // For debugging purposes, it can be helpful to synchronize after each message
 // rather than after each iteration, to see which messages are particularly
 // slow or cause a hang. Without this, synchronization will occur at the end
 // of each iteration as well as after each constructor message.
-//#define MOZ_FUZZ_IPC_SYNC_AFTER_EACH_MSG
+// #define MOZ_FUZZ_IPC_SYNC_AFTER_EACH_MSG

 namespace mozilla {
 namespace fuzzing {
@ -621,7 +621,7 @@ NS_IMETHODIMP IPCFuzzController::IPCFuzzLoop::Run() {
  IPCFuzzController::instance().runnableDone = false;

  SyncRunnable::DispatchToThread(
-      GetMainThreadEventTarget(),
+      GetMainThreadSerialEventTarget(),
      NS_NewRunnableFunction("IPCFuzzController::StartFuzzing", [&]() -> void {
        MOZ_FUZZING_NYX_PRINT("INFO: Main thread runnable start.\n");
        NS_ProcessPendingEvents(NS_GetCurrentThread());
--- a/xpcom/base/RLBoxSandboxPool.cpp
+++ b/xpcom/base/RLBoxSandboxPool.cpp
@ -32,7 +32,7 @@ void RLBoxSandboxPool::StartTimer() {
  }
  DebugOnly<nsresult> rv = NS_NewTimerWithCallback(
      getter_AddRefs(mTimer), this, mDelaySeconds * 1000,
-      nsITimer::TYPE_ONE_SHOT, GetMainThreadEventTarget());
+      nsITimer::TYPE_ONE_SHOT, GetMainThreadSerialEventTarget());
  MOZ_ASSERT(NS_SUCCEEDED(rv), "failed to create timer");
 }

--- a/xpcom/threads/nsThreadUtils.cpp
+++ b/xpcom/threads/nsThreadUtils.cpp
@ -547,10 +547,6 @@ nsAutoLowPriorityIO::~nsAutoLowPriorityIO() {

 namespace mozilla {

-nsIEventTarget* GetMainThreadEventTarget() {
-  return GetMainThreadSerialEventTarget();
-}
-
 nsISerialEventTarget* GetCurrentSerialEventTarget() {
  if (nsISerialEventTarget* current =
          SerialEventTargetGuard::GetCurrentSerialEventTarget()) {
--- a/xpcom/threads/nsThreadUtils.h
+++ b/xpcom/threads/nsThreadUtils.h
@ -1797,10 +1797,6 @@ class SerialEventTargetGuard {
  nsISerialEventTarget* mLastCurrentThread;
 };

-// See GetMainThreadSerialEventTarget()
-
-nsIEventTarget* GetMainThreadEventTarget();
-
 // Get the serial event target corresponding to the currently executing task
 // queue or thread. This method will assert if called on a thread pool without
 // an active task queue.