Merging upstream version 127.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 1582 insertions, 501 deletions

diff --git a/dom/media/gtest/AudioVerifier.h b/dom/media/gtest/AudioVerifier.h
index ba67f6e489..2ff8ed9269 100644
--- a/dom/media/gtest/AudioVerifier.h
+++ b/dom/media/gtest/AudioVerifier.h
@@ -99,7 +99,7 @@ class AudioVerifier {
   void CountZeroCrossing(Sample aCurrentSample) {
     if (mPrevious > 0 && aCurrentSample <= 0) {
       if (mZeroCrossCount++) {
-        MOZ_ASSERT(mZeroCrossCount > 1);
+        MOZ_RELEASE_ASSERT(mZeroCrossCount > 1);
         mSumPeriodInSamples += mTotalFramesSoFar - mLastZeroCrossPosition;
       }
       mLastZeroCrossPosition = mTotalFramesSoFar;
@@ -120,7 +120,7 @@ class AudioVerifier {
       return;
     }
 
-    MOZ_ASSERT(mCurrentDiscontinuityFrameCount == 0);
+    MOZ_RELEASE_ASSERT(mCurrentDiscontinuityFrameCount == 0);
     if (!discontinuity) {
       return;
     }
diff --git a/dom/media/gtest/GMPTestMonitor.h b/dom/media/gtest/GMPTestMonitor.h
index 27477b6a42..9f4e8f0a84 100644
--- a/dom/media/gtest/GMPTestMonitor.h
+++ b/dom/media/gtest/GMPTestMonitor.h
@@ -15,7 +15,7 @@ class GMPTestMonitor {
   GMPTestMonitor() : mFinished(false) {}
 
   void AwaitFinished() {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     mozilla::SpinEventLoopUntil("GMPTestMonitor::AwaitFinished"_ns,
                                 [&]() { return mFinished; });
     mFinished = false;
@@ -23,7 +23,7 @@ class GMPTestMonitor {
 
  private:
   void MarkFinished() {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     mFinished = true;
   }
 
diff --git a/dom/media/gtest/MockCubeb.cpp b/dom/media/gtest/MockCubeb.cpp
index ae3a676ac8..9d61ccf4b5 100644
--- a/dom/media/gtest/MockCubeb.cpp
+++ b/dom/media/gtest/MockCubeb.cpp
@@ -168,79 +168,93 @@ MockCubebStream::MockCubebStream(
       mAudioVerifier(aInputStreamParams ? aInputStreamParams->rate
                                         : aOutputStreamParams->rate,
                      100 /* aFrequency */) {
-  MOZ_ASSERT(mAudioGenerator.ChannelCount() <= MAX_INPUT_CHANNELS,
-             "mInputBuffer has no enough space to hold generated data");
-  MOZ_ASSERT_IF(mFrozenStart, mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mAudioGenerator.ChannelCount() <= MAX_INPUT_CHANNELS,
+                     "mInputBuffer has no enough space to hold generated data");
+  if (mFrozenStart) {
+    MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
+  }
   if (aInputStreamParams) {
     mInputParams = *aInputStreamParams;
   }
   if (aOutputStreamParams) {
     mOutputParams = *aOutputStreamParams;
-    MOZ_ASSERT(SampleRate() == mOutputParams.rate);
+    MOZ_RELEASE_ASSERT(SampleRate() == mOutputParams.rate);
   }
 }
 
 MockCubebStream::~MockCubebStream() = default;
 
 int MockCubebStream::Start() {
-  NotifyState(CUBEB_STATE_STARTED);
-  mStreamStop = false;
-  if (mFrozenStart) {
-    // We need to grab mFrozenStartMonitor before returning to avoid races in
-    // the calling code -- it controls when to mFrozenStartMonitor.Notify().
-    // TempData helps facilitate this by holding what's needed to block the
-    // calling thread until the background thread has grabbed the lock.
-    struct TempData {
-      NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TempData)
-      static_assert(HasThreadSafeRefCnt::value,
-                    "Silence a -Wunused-local-typedef warning");
-      Monitor mMonitor{"MockCubebStream::Start::TempData::mMonitor"};
-      bool mFinished = false;
-
-     private:
-      ~TempData() = default;
-    };
-    auto temp = MakeRefPtr<TempData>();
-    MonitorAutoLock lock(temp->mMonitor);
-    NS_DispatchBackgroundTask(NS_NewRunnableFunction(
-        "MockCubebStream::WaitForThawBeforeStart",
-        [temp, this, self = RefPtr<SmartMockCubebStream>(mSelf)]() mutable {
-          MonitorAutoLock lock(mFrozenStartMonitor);
-          {
-            // Unblock MockCubebStream::Start now that we have locked the frozen
-            // start monitor.
-            MonitorAutoLock tempLock(temp->mMonitor);
-            temp->mFinished = true;
-            temp->mMonitor.Notify();
-            temp = nullptr;
-          }
-          while (mFrozenStart) {
-            mFrozenStartMonitor.Wait();
-          }
-          if (!mStreamStop) {
+  {
+    MutexAutoLock l(mMutex);
+    NotifyState(CUBEB_STATE_STARTED);
+  }
+  {
+    MonitorAutoLock lock(mFrozenStartMonitor);
+    if (mFrozenStart) {
+      // We need to grab mFrozenStartMonitor before returning to avoid races in
+      // the calling code -- it controls when to mFrozenStartMonitor.Notify().
+      // TempData helps facilitate this by holding what's needed to block the
+      // calling thread until the background thread has grabbed the lock.
+      struct TempData {
+        NS_INLINE_DECL_THREADSAFE_REFCOUNTING(TempData)
+        static_assert(HasThreadSafeRefCnt::value,
+                      "Silence a -Wunused-local-typedef warning");
+        Monitor mMonitor{"MockCubebStream::Start::TempData::mMonitor"};
+        bool mFinished = false;
+
+       private:
+        ~TempData() = default;
+      };
+      auto temp = MakeRefPtr<TempData>();
+      MonitorAutoLock lock(temp->mMonitor);
+      NS_DispatchBackgroundTask(NS_NewRunnableFunction(
+          "MockCubebStream::WaitForThawBeforeStart",
+          [temp, this, self = RefPtr<SmartMockCubebStream>(mSelf)]() mutable {
+            {
+              // Unblock MockCubebStream::Start now that we have locked the
+              // frozen start monitor.
+              MonitorAutoLock tempLock(temp->mMonitor);
+              temp->mFinished = true;
+              temp->mMonitor.Notify();
+              temp = nullptr;
+            }
+            {
+              MonitorAutoLock lock(mFrozenStartMonitor);
+              while (mFrozenStart) {
+                mFrozenStartMonitor.Wait();
+              }
+            }
+            if (MutexAutoLock l(mMutex);
+                !mState || *mState != CUBEB_STATE_STARTED) {
+              return;
+            }
             MockCubeb::AsMock(context)->StartStream(mSelf);
-          }
-        }));
-    while (!temp->mFinished) {
-      temp->mMonitor.Wait();
+          }));
+      while (!temp->mFinished) {
+        temp->mMonitor.Wait();
+      }
+      return CUBEB_OK;
     }
-    return CUBEB_OK;
   }
   MockCubeb::AsMock(context)->StartStream(this);
   return CUBEB_OK;
 }
 
 int MockCubebStream::Stop() {
+  MockCubeb::AsMock(context)->StopStream(this);
+  MutexAutoLock l(mMutex);
   mOutputVerificationEvent.Notify(std::make_tuple(
       mAudioVerifier.PreSilenceSamples(), mAudioVerifier.EstimatedFreq(),
       mAudioVerifier.CountDiscontinuities()));
-  MockCubeb::AsMock(context)->StopStream(this);
-  mStreamStop = true;
   NotifyState(CUBEB_STATE_STOPPED);
   return CUBEB_OK;
 }
 
-uint64_t MockCubebStream::Position() { return mPosition; }
+uint64_t MockCubebStream::Position() {
+  MutexAutoLock l(mMutex);
+  return mPosition;
+}
 
 void MockCubebStream::Destroy() {
   // Stop() even if cubeb_stream_stop() has already been called, as with
@@ -248,11 +262,15 @@ void MockCubebStream::Destroy() {
   // This provides an extra STOPPED state callback as with audioipc.
   // It also ensures that this stream is removed from MockCubeb::mLiveStreams.
   Stop();
-  mDestroyed = true;
+  {
+    MutexAutoLock l(mMutex);
+    mDestroyed = true;
+  }
   MockCubeb::AsMock(context)->StreamDestroy(this);
 }
 
 int MockCubebStream::SetName(char const* aName) {
+  MutexAutoLock l(mMutex);
   mName = aName;
   mNameSetEvent.Notify(mName);
   return CUBEB_OK;
@@ -260,6 +278,7 @@ int MockCubebStream::SetName(char const* aName) {
 
 int MockCubebStream::RegisterDeviceChangedCallback(
     cubeb_device_changed_callback aDeviceChangedCallback) {
+  MutexAutoLock l(mMutex);
   if (mDeviceChangedCallback && aDeviceChangedCallback) {
     return CUBEB_ERROR_INVALID_PARAMETER;
   }
@@ -267,14 +286,41 @@ int MockCubebStream::RegisterDeviceChangedCallback(
   return CUBEB_OK;
 }
 
+int MockCubebStream::SetInputProcessingParams(
+    cubeb_input_processing_params aParams) {
+  MockCubeb* mock = MockCubeb::AsMock(context);
+  auto res = mock->SupportedInputProcessingParams();
+  if (res.isErr()) {
+    return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+  cubeb_input_processing_params supported = res.unwrap();
+  if ((supported & aParams) != aParams) {
+    return CUBEB_ERROR_INVALID_PARAMETER;
+  }
+  return mock->InputProcessingApplyRv();
+}
+
 cubeb_stream* MockCubebStream::AsCubebStream() {
-  MOZ_ASSERT(!mDestroyed);
+  MutexAutoLock l(mMutex);
+  return AsCubebStreamLocked();
+}
+
+cubeb_stream* MockCubebStream::AsCubebStreamLocked() {
+  MOZ_RELEASE_ASSERT(!mDestroyed);
+  mMutex.AssertCurrentThreadOwns();
   return reinterpret_cast<cubeb_stream*>(this);
 }
 
 MockCubebStream* MockCubebStream::AsMock(cubeb_stream* aStream) {
   auto* mockStream = reinterpret_cast<MockCubebStream*>(aStream);
-  MOZ_ASSERT(!mockStream->mDestroyed);
+  MutexAutoLock l(mockStream->mMutex);
+  return AsMockLocked(aStream);
+}
+
+MockCubebStream* MockCubebStream::AsMockLocked(cubeb_stream* aStream) {
+  auto* mockStream = reinterpret_cast<MockCubebStream*>(aStream);
+  mockStream->mMutex.AssertCurrentThreadOwns();
+  MOZ_RELEASE_ASSERT(!mockStream->mDestroyed);
   return mockStream;
 }
 
@@ -285,58 +331,96 @@ cubeb_devid MockCubebStream::GetOutputDeviceID() const {
 }
 
 uint32_t MockCubebStream::InputChannels() const {
+  MutexAutoLock l(mMutex);
+  return InputChannelsLocked();
+}
+
+uint32_t MockCubebStream::InputChannelsLocked() const {
+  mMutex.AssertCurrentThreadOwns();
   return mAudioGenerator.ChannelCount();
 }
 
 uint32_t MockCubebStream::OutputChannels() const {
+  MutexAutoLock l(mMutex);
+  return OutputChannelsLocked();
+}
+
+uint32_t MockCubebStream::OutputChannelsLocked() const {
+  mMutex.AssertCurrentThreadOwns();
   return mOutputParams.channels;
 }
 
 uint32_t MockCubebStream::SampleRate() const {
+  MutexAutoLock l(mMutex);
+  return SampleRateLocked();
+}
+
+uint32_t MockCubebStream::SampleRateLocked() const {
+  mMutex.AssertCurrentThreadOwns();
   return mAudioGenerator.mSampleRate;
 }
 
 uint32_t MockCubebStream::InputFrequency() const {
+  MutexAutoLock l(mMutex);
+  return InputFrequencyLocked();
+}
+
+uint32_t MockCubebStream::InputFrequencyLocked() const {
+  mMutex.AssertCurrentThreadOwns();
   return mAudioGenerator.mFrequency;
 }
 
+Maybe<cubeb_state> MockCubebStream::State() const {
+  MutexAutoLock l(mMutex);
+  return mState;
+}
+
 nsTArray<AudioDataValue>&& MockCubebStream::TakeRecordedOutput() {
+  MutexAutoLock l(mMutex);
   return std::move(mRecordedOutput);
 }
 
 nsTArray<AudioDataValue>&& MockCubebStream::TakeRecordedInput() {
+  MutexAutoLock l(mMutex);
   return std::move(mRecordedInput);
 }
 
 void MockCubebStream::SetDriftFactor(float aDriftFactor) {
-  MOZ_ASSERT(mRunningMode == MockCubeb::RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == MockCubeb::RunningMode::Automatic);
+  MutexAutoLock l(mMutex);
   mDriftFactor = aDriftFactor;
 }
 
-void MockCubebStream::ForceError() { mForceErrorState = true; }
+void MockCubebStream::ForceError() {
+  MutexAutoLock l(mMutex);
+  mForceErrorState = true;
+}
 
 void MockCubebStream::ForceDeviceChanged() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
+  MutexAutoLock l(mMutex);
   mForceDeviceChanged = true;
 };
 
 void MockCubebStream::NotifyDeviceChangedNow() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Manual);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Manual);
   NotifyDeviceChanged();
 }
 
 void MockCubebStream::Thaw() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
   MonitorAutoLock l(mFrozenStartMonitor);
   mFrozenStart = false;
   mFrozenStartMonitor.Notify();
 }
 
 void MockCubebStream::SetOutputRecordingEnabled(bool aEnabled) {
+  MutexAutoLock l(mMutex);
   mOutputRecordingEnabled = aEnabled;
 }
 
 void MockCubebStream::SetInputRecordingEnabled(bool aEnabled) {
+  MutexAutoLock l(mMutex);
   mInputRecordingEnabled = aEnabled;
 }
 
@@ -370,33 +454,43 @@ MediaEventSource<void>& MockCubebStream::DeviceChangeForcedEvent() {
 }
 
 KeepProcessing MockCubebStream::ManualDataCallback(long aNrFrames) {
-  MOZ_ASSERT(mRunningMode == RunningMode::Manual);
-  MOZ_ASSERT(aNrFrames <= kMaxNrFrames);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Manual);
+  MOZ_RELEASE_ASSERT(aNrFrames <= kMaxNrFrames);
+  MutexAutoLock l(mMutex);
   return Process(aNrFrames);
 }
 
 KeepProcessing MockCubebStream::Process(long aNrFrames) {
+  mMutex.AssertCurrentThreadOwns();
+  if (!mState || *mState != CUBEB_STATE_STARTED) {
+    return KeepProcessing::InvalidState;
+  }
   if (mInputParams.rate) {
     mAudioGenerator.GenerateInterleaved(mInputBuffer, aNrFrames);
   }
-  cubeb_stream* stream = AsCubebStream();
+  cubeb_stream* stream = AsCubebStreamLocked();
   const long outframes =
       mDataCallback(stream, mUserPtr, mHasInput ? mInputBuffer : nullptr,
                     mHasOutput ? mOutputBuffer : nullptr, aNrFrames);
 
-  if (mInputRecordingEnabled && mHasInput) {
-    mRecordedInput.AppendElements(mInputBuffer, outframes * InputChannels());
-  }
-  if (mOutputRecordingEnabled && mHasOutput) {
-    mRecordedOutput.AppendElements(mOutputBuffer, outframes * OutputChannels());
-  }
-  mAudioVerifier.AppendDataInterleaved(mOutputBuffer, outframes,
-                                       MAX_OUTPUT_CHANNELS);
-  mPosition += outframes;
+  if (outframes > 0) {
+    if (mInputRecordingEnabled && mHasInput) {
+      mRecordedInput.AppendElements(mInputBuffer,
+                                    outframes * InputChannelsLocked());
+    }
+    if (mOutputRecordingEnabled && mHasOutput) {
+      mRecordedOutput.AppendElements(mOutputBuffer,
+
+                                     outframes * OutputChannelsLocked());
+    }
+    mAudioVerifier.AppendDataInterleaved(mOutputBuffer, outframes,
+                                         MAX_OUTPUT_CHANNELS);
+    mPosition += outframes;
 
-  mFramesProcessedEvent.Notify(outframes);
-  if (mAudioVerifier.PreSilenceEnded()) {
-    mFramesVerifiedEvent.Notify(outframes);
+    mFramesProcessedEvent.Notify(outframes);
+    if (mAudioVerifier.PreSilenceEnded()) {
+      mFramesVerifiedEvent.Notify(outframes);
+    }
   }
 
   if (outframes < aNrFrames) {
@@ -422,8 +516,9 @@ KeepProcessing MockCubebStream::Process(long aNrFrames) {
 }
 
 KeepProcessing MockCubebStream::Process10Ms() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
-  uint32_t rate = SampleRate();
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
+  MutexAutoLock l(mMutex);
+  uint32_t rate = SampleRateLocked();
   const long nrFrames =
       static_cast<long>(static_cast<float>(rate * 10) * mDriftFactor) /
       PR_MSEC_PER_SEC;
@@ -431,11 +526,14 @@ KeepProcessing MockCubebStream::Process10Ms() {
 }
 
 void MockCubebStream::NotifyState(cubeb_state aState) {
-  mStateCallback(AsCubebStream(), mUserPtr, aState);
+  mMutex.AssertCurrentThreadOwns();
+  mState = Some(aState);
+  mStateCallback(AsCubebStreamLocked(), mUserPtr, aState);
   mStateEvent.Notify(aState);
 }
 
 void MockCubebStream::NotifyDeviceChanged() {
+  MutexAutoLock l(mMutex);
   mDeviceChangedCallback(this->mUserPtr);
   mDeviceChangedForcedEvent.Notify();
 }
@@ -445,20 +543,20 @@ MockCubeb::MockCubeb() : MockCubeb(MockCubeb::RunningMode::Automatic) {}
 MockCubeb::MockCubeb(RunningMode aRunningMode)
     : ops(&mock_ops), mRunningMode(aRunningMode) {}
 
-MockCubeb::~MockCubeb() { MOZ_ASSERT(!mFakeAudioThread); };
+MockCubeb::~MockCubeb() { MOZ_RELEASE_ASSERT(!mFakeAudioThread); };
 
 void MockCubeb::Destroy() {
-  MOZ_ASSERT(mHasCubebContext);
+  MOZ_RELEASE_ASSERT(mHasCubebContext);
   {
     auto streams = mLiveStreams.Lock();
-    MOZ_ASSERT(streams->IsEmpty());
+    MOZ_RELEASE_ASSERT(streams->IsEmpty());
   }
   mDestroyed = true;
   Release();
 }
 
 cubeb* MockCubeb::AsCubebContext() {
-  MOZ_ASSERT(!mDestroyed);
+  MOZ_RELEASE_ASSERT(!mDestroyed);
   if (mHasCubebContext.compareExchange(false, true)) {
     AddRef();
   }
@@ -467,7 +565,7 @@ cubeb* MockCubeb::AsCubebContext() {
 
 MockCubeb* MockCubeb::AsMock(cubeb* aContext) {
   auto* mockCubeb = reinterpret_cast<MockCubeb*>(aContext);
-  MOZ_ASSERT(!mockCubeb->mDestroyed);
+  MOZ_RELEASE_ASSERT(!mockCubeb->mDestroyed);
   return mockCubeb;
 }
 
@@ -528,6 +626,28 @@ int MockCubeb::RegisterDeviceCollectionChangeCallback(
   return CUBEB_OK;
 }
 
+Result<cubeb_input_processing_params, int>
+MockCubeb::SupportedInputProcessingParams() const {
+  const auto& [params, rv] = mSupportedInputProcessingParams;
+  if (rv != CUBEB_OK) {
+    return Err(rv);
+  }
+  return params;
+}
+
+void MockCubeb::SetSupportedInputProcessingParams(
+    cubeb_input_processing_params aParams, int aRv) {
+  mSupportedInputProcessingParams = std::make_pair(aParams, aRv);
+}
+
+void MockCubeb::SetInputProcessingApplyRv(int aRv) {
+  mInputProcessingParamsApplyRv = aRv;
+}
+
+int MockCubeb::InputProcessingApplyRv() const {
+  return mInputProcessingParamsApplyRv;
+}
+
 void MockCubeb::AddDevice(cubeb_device_info aDevice) {
   if (aDevice.type == CUBEB_DEVICE_TYPE_INPUT) {
     mInputDevices.AppendElement(aDevice);
@@ -613,12 +733,12 @@ void MockCubeb::SetSupportDeviceChangeCallback(bool aSupports) {
 void MockCubeb::ForceStreamInitError() { mStreamInitErrorState = true; }
 
 void MockCubeb::SetStreamStartFreezeEnabled(bool aEnabled) {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
   mStreamStartFreezeEnabled = aEnabled;
 }
 
 auto MockCubeb::ForceAudioThread() -> RefPtr<ForcedAudioThreadPromise> {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
   RefPtr<ForcedAudioThreadPromise> p =
       mForcedAudioThreadPromise.Ensure(__func__);
   mForcedAudioThread = true;
@@ -627,7 +747,7 @@ auto MockCubeb::ForceAudioThread() -> RefPtr<ForcedAudioThreadPromise> {
 }
 
 void MockCubeb::UnforceAudioThread() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
   mForcedAudioThread = false;
 }
 
@@ -660,12 +780,12 @@ void MockCubeb::StreamDestroy(MockCubebStream* aStream) {
 }
 
 void MockCubeb::GoFaster() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
   mFastMode = true;
 }
 
 void MockCubeb::DontGoFaster() {
-  MOZ_ASSERT(mRunningMode == RunningMode::Automatic);
+  MOZ_RELEASE_ASSERT(mRunningMode == RunningMode::Automatic);
   mFastMode = false;
 }
 
@@ -679,13 +799,17 @@ MockCubeb::StreamDestroyEvent() {
 }
 
 void MockCubeb::StartStream(MockCubebStream* aStream) {
+  if (aStream) {
+    aStream->mMutex.AssertNotCurrentThreadOwns();
+  }
   auto streams = mLiveStreams.Lock();
-  MOZ_ASSERT_IF(!aStream, mForcedAudioThread);
-  // Forcing an audio thread must happen before starting streams
-  MOZ_ASSERT_IF(!aStream, streams->IsEmpty());
   if (aStream) {
-    MOZ_ASSERT(!streams->Contains(aStream->mSelf));
+    MOZ_RELEASE_ASSERT(!streams->Contains(aStream->mSelf));
     streams->AppendElement(aStream->mSelf);
+  } else {
+    MOZ_RELEASE_ASSERT(mForcedAudioThread);
+    // Forcing an audio thread must happen before starting streams
+    MOZ_RELEASE_ASSERT(streams->IsEmpty());
   }
   if (!mFakeAudioThread && mRunningMode == RunningMode::Automatic) {
     AddRef();  // released when the thread exits
@@ -694,6 +818,7 @@ void MockCubeb::StartStream(MockCubebStream* aStream) {
 }
 
 void MockCubeb::StopStream(MockCubebStream* aStream) {
+  aStream->mMutex.AssertNotCurrentThreadOwns();
   {
     auto streams = mLiveStreams.Lock();
     if (!streams->Contains(aStream->mSelf)) {
@@ -719,7 +844,7 @@ void MockCubeb::ThreadFunction() {
         }
       }
       streams->RemoveElementsBy([](const auto& stream) { return !stream; });
-      MOZ_ASSERT(mFakeAudioThread);
+      MOZ_RELEASE_ASSERT(mFakeAudioThread);
       if (streams->IsEmpty() && !mForcedAudioThread) {
         // This leaks the std::thread if Gecko's main thread has already been
         // shut down.
diff --git a/dom/media/gtest/MockCubeb.h b/dom/media/gtest/MockCubeb.h
index ed6342a779..15689a4a4e 100644
--- a/dom/media/gtest/MockCubeb.h
+++ b/dom/media/gtest/MockCubeb.h
@@ -11,12 +11,15 @@
 #include "MediaEventSource.h"
 #include "mozilla/DataMutex.h"
 #include "mozilla/MozPromise.h"
+#include "mozilla/Result.h"
+#include "mozilla/ResultVariant.h"
 #include "mozilla/ThreadSafeWeakPtr.h"
 #include "nsTArray.h"
 
 #include <thread>
 #include <atomic>
 #include <chrono>
+#include <utility>
 
 namespace mozilla {
 const uint32_t MAX_OUTPUT_CHANNELS = 2;
@@ -68,6 +71,8 @@ struct cubeb_ops {
 // Keep those and the struct definition in sync with cubeb.h and
 // cubeb-internal.h
 void cubeb_mock_destroy(cubeb* context);
+static int cubeb_mock_get_supported_input_processing_params(
+    cubeb* context, cubeb_input_processing_params* params);
 static int cubeb_mock_enumerate_devices(cubeb* context, cubeb_device_type type,
                                         cubeb_device_collection* out);
 
@@ -101,6 +106,9 @@ static int cubeb_mock_stream_set_volume(cubeb_stream* stream, float volume);
 static int cubeb_mock_stream_set_name(cubeb_stream* stream,
                                       char const* stream_name);
 
+static int cubeb_mock_stream_set_input_processing_params(
+    cubeb_stream* stream, cubeb_input_processing_params);
+
 static int cubeb_mock_stream_register_device_changed_callback(
     cubeb_stream* stream,
     cubeb_device_changed_callback device_changed_callback);
@@ -122,7 +130,7 @@ cubeb_ops const mock_ops = {
     /*.get_min_latency =*/cubeb_mock_get_min_latency,
     /*.get_preferred_sample_rate =*/cubeb_mock_get_preferred_sample_rate,
     /*.get_supported_input_processing_params =*/
-    NULL,
+    cubeb_mock_get_supported_input_processing_params,
     /*.enumerate_devices =*/cubeb_mock_enumerate_devices,
     /*.device_collection_destroy =*/cubeb_mock_device_collection_destroy,
     /*.destroy =*/cubeb_mock_destroy,
@@ -139,7 +147,7 @@ cubeb_ops const mock_ops = {
 
     /*.stream_set_input_mute =*/NULL,
     /*.stream_set_input_processing_params =*/
-    NULL,
+    cubeb_mock_stream_set_input_processing_params,
     /*.stream_device_destroy =*/NULL,
     /*.stream_register_device_changed_callback =*/
     cubeb_mock_stream_register_device_changed_callback,
@@ -160,7 +168,7 @@ class MockCubebStream {
   void* mUserPtr;
 
  public:
-  enum class KeepProcessing { No, Yes };
+  enum class KeepProcessing { No, Yes, InvalidState };
   enum class RunningMode { Automatic, Manual };
 
   MockCubebStream(cubeb* aContext, char const* aStreamName,
@@ -175,50 +183,56 @@ class MockCubebStream {
 
   ~MockCubebStream();
 
-  int Start();
-  int Stop();
-  uint64_t Position();
-  void Destroy();
-  int SetName(char const* aName);
+  int Start() MOZ_EXCLUDES(mMutex);
+  int Stop() MOZ_EXCLUDES(mMutex);
+  uint64_t Position() MOZ_EXCLUDES(mMutex);
+  void Destroy() MOZ_EXCLUDES(mMutex);
+  int SetName(char const* aName) MOZ_EXCLUDES(mMutex);
   int RegisterDeviceChangedCallback(
-      cubeb_device_changed_callback aDeviceChangedCallback);
+      cubeb_device_changed_callback aDeviceChangedCallback)
+      MOZ_EXCLUDES(mMutex);
+  int SetInputProcessingParams(cubeb_input_processing_params aParams);
 
-  cubeb_stream* AsCubebStream();
+  cubeb_stream* AsCubebStream() MOZ_EXCLUDES(mMutex);
   static MockCubebStream* AsMock(cubeb_stream* aStream);
 
-  char const* StreamName() const { return mName.get(); }
+  char const* StreamName() const MOZ_EXCLUDES(mMutex) {
+    MutexAutoLock l(mMutex);
+    return mName.get();
+  }
   cubeb_devid GetInputDeviceID() const;
   cubeb_devid GetOutputDeviceID() const;
 
-  uint32_t InputChannels() const;
-  uint32_t OutputChannels() const;
-  uint32_t SampleRate() const;
-  uint32_t InputFrequency() const;
+  uint32_t InputChannels() const MOZ_EXCLUDES(mMutex);
+  uint32_t OutputChannels() const MOZ_EXCLUDES(mMutex);
+  uint32_t SampleRate() const MOZ_EXCLUDES(mMutex);
+  uint32_t InputFrequency() const MOZ_EXCLUDES(mMutex);
+  Maybe<cubeb_state> State() const MOZ_EXCLUDES(mMutex);
 
-  void SetDriftFactor(float aDriftFactor);
-  void ForceError();
-  void ForceDeviceChanged();
-  void Thaw();
+  void SetDriftFactor(float aDriftFactor) MOZ_EXCLUDES(mMutex);
+  void ForceError() MOZ_EXCLUDES(mMutex);
+  void ForceDeviceChanged() MOZ_EXCLUDES(mMutex);
+  void Thaw() MOZ_EXCLUDES(mMutex);
 
   // For RunningMode::Manual, drive this MockCubebStream forward.
-  KeepProcessing ManualDataCallback(long aNrFrames);
+  KeepProcessing ManualDataCallback(long aNrFrames) MOZ_EXCLUDES(mMutex);
 
   // For RunningMode::Manual, notify the client of a DeviceChanged event
   // synchronously.
-  void NotifyDeviceChangedNow();
+  void NotifyDeviceChangedNow() MOZ_EXCLUDES(mMutex);
 
   // Enable input recording for this driver. This is best called before
   // the thread is running, but is safe to call whenever.
-  void SetOutputRecordingEnabled(bool aEnabled);
+  void SetOutputRecordingEnabled(bool aEnabled) MOZ_EXCLUDES(mMutex);
   // Enable input recording for this driver. This is best called before
   // the thread is running, but is safe to call whenever.
-  void SetInputRecordingEnabled(bool aEnabled);
+  void SetInputRecordingEnabled(bool aEnabled) MOZ_EXCLUDES(mMutex);
   // Get the recorded output from this stream. This doesn't copy, and therefore
   // only works once.
-  nsTArray<AudioDataValue>&& TakeRecordedOutput();
+  nsTArray<AudioDataValue>&& TakeRecordedOutput() MOZ_EXCLUDES(mMutex);
   // Get the recorded input from this stream. This doesn't copy, and therefore
   // only works once.
-  nsTArray<AudioDataValue>&& TakeRecordedInput();
+  nsTArray<AudioDataValue>&& TakeRecordedInput() MOZ_EXCLUDES(mMutex);
 
   MediaEventSource<nsCString>& NameSetEvent();
   MediaEventSource<cubeb_state>& StateEvent();
@@ -232,7 +246,13 @@ class MockCubebStream {
   MediaEventSource<void>& DeviceChangeForcedEvent();
 
  private:
-  KeepProcessing Process(long aNrFrames);
+  cubeb_stream* AsCubebStreamLocked() MOZ_REQUIRES(mMutex);
+  static MockCubebStream* AsMockLocked(cubeb_stream* aStream);
+  uint32_t InputChannelsLocked() const MOZ_REQUIRES(mMutex);
+  uint32_t OutputChannelsLocked() const MOZ_REQUIRES(mMutex);
+  uint32_t SampleRateLocked() const MOZ_REQUIRES(mMutex);
+  uint32_t InputFrequencyLocked() const MOZ_REQUIRES(mMutex);
+  KeepProcessing Process(long aNrFrames) MOZ_REQUIRES(mMutex);
   KeepProcessing Process10Ms();
 
  public:
@@ -242,52 +262,58 @@ class MockCubebStream {
   SmartMockCubebStream* const mSelf;
 
  private:
-  void NotifyState(cubeb_state aState);
-  void NotifyDeviceChanged();
+  void NotifyState(cubeb_state aState) MOZ_REQUIRES(mMutex);
+  void NotifyDeviceChanged() MOZ_EXCLUDES(mMutex);
 
   static constexpr long kMaxNrFrames = 1920;
+  // Mutex guarding most members to ensure state is in sync.
+  mutable Mutex mMutex{"MockCubebStream::mMutex"};
   // Monitor used to block start until mFrozenStart is false.
-  Monitor mFrozenStartMonitor MOZ_UNANNOTATED;
+  Monitor mFrozenStartMonitor MOZ_ACQUIRED_BEFORE(mMutex);
   // Whether this stream should wait for an explicit start request before
-  // starting. Protected by FrozenStartMonitor.
-  bool mFrozenStart;
+  // starting.
+  bool mFrozenStart MOZ_GUARDED_BY(mFrozenStartMonitor);
+  // The stream's most recently issued state change, if any has occurred.
   // Used to abort a frozen start if cubeb_stream_start() is called currently
   // with a blocked cubeb_stream_start() call.
-  std::atomic_bool mStreamStop{true};
+  Maybe<cubeb_state> mState MOZ_GUARDED_BY(mMutex);
   // Whether or not the output-side of this stream (what is written from the
   // callback output buffer) is recorded in an internal buffer. The data is then
   // available via `GetRecordedOutput`.
-  std::atomic_bool mOutputRecordingEnabled{false};
+  bool mOutputRecordingEnabled MOZ_GUARDED_BY(mMutex) = false;
   // Whether or not the input-side of this stream (what is written from the
   // callback input buffer) is recorded in an internal buffer. The data is then
   // available via `TakeRecordedInput`.
-  std::atomic_bool mInputRecordingEnabled{false};
+  bool mInputRecordingEnabled MOZ_GUARDED_BY(mMutex) = false;
   // The audio buffer used on data callback.
-  AudioDataValue mOutputBuffer[MAX_OUTPUT_CHANNELS * kMaxNrFrames] = {};
-  AudioDataValue mInputBuffer[MAX_INPUT_CHANNELS * kMaxNrFrames] = {};
+  AudioDataValue mOutputBuffer[MAX_OUTPUT_CHANNELS *
+                               kMaxNrFrames] MOZ_GUARDED_BY(mMutex) = {};
+  AudioDataValue mInputBuffer[MAX_INPUT_CHANNELS * kMaxNrFrames] MOZ_GUARDED_BY(
+      mMutex) = {};
   // The audio callback
-  cubeb_data_callback mDataCallback = nullptr;
+  const cubeb_data_callback mDataCallback = nullptr;
   // The stream state callback
-  cubeb_state_callback mStateCallback = nullptr;
+  const cubeb_state_callback mStateCallback = nullptr;
   // The device changed callback
-  cubeb_device_changed_callback mDeviceChangedCallback = nullptr;
+  cubeb_device_changed_callback mDeviceChangedCallback MOZ_GUARDED_BY(mMutex) =
+      nullptr;
   // A name for this stream
-  nsCString mName;
+  nsCString mName MOZ_GUARDED_BY(mMutex);
   // The stream params
-  cubeb_stream_params mOutputParams = {};
-  cubeb_stream_params mInputParams = {};
+  cubeb_stream_params mOutputParams MOZ_GUARDED_BY(mMutex) = {};
+  cubeb_stream_params mInputParams MOZ_GUARDED_BY(mMutex) = {};
   /* Device IDs */
-  cubeb_devid mInputDeviceID;
-  cubeb_devid mOutputDeviceID;
-
-  std::atomic<float> mDriftFactor{1.0};
-  std::atomic_bool mFastMode{false};
-  std::atomic_bool mForceErrorState{false};
-  std::atomic_bool mForceDeviceChanged{false};
-  std::atomic_bool mDestroyed{false};
-  std::atomic<uint64_t> mPosition{0};
-  AudioGenerator<AudioDataValue> mAudioGenerator;
-  AudioVerifier<AudioDataValue> mAudioVerifier;
+  const cubeb_devid mInputDeviceID;
+  const cubeb_devid mOutputDeviceID;
+
+  float mDriftFactor MOZ_GUARDED_BY(mMutex) = 1.0;
+  bool mFastMode MOZ_GUARDED_BY(mMutex) = false;
+  bool mForceErrorState MOZ_GUARDED_BY(mMutex) = false;
+  bool mForceDeviceChanged MOZ_GUARDED_BY(mMutex) = false;
+  bool mDestroyed MOZ_GUARDED_BY(mMutex) = false;
+  uint64_t mPosition MOZ_GUARDED_BY(mMutex) = 0;
+  AudioGenerator<AudioDataValue> mAudioGenerator MOZ_GUARDED_BY(mMutex);
+  AudioVerifier<AudioDataValue> mAudioVerifier MOZ_GUARDED_BY(mMutex);
 
   MediaEventProducer<nsCString> mNameSetEvent;
   MediaEventProducer<cubeb_state> mStateEvent;
@@ -299,12 +325,29 @@ class MockCubebStream {
   MediaEventProducer<void> mDeviceChangedForcedEvent;
   // The recorded data, copied from the output_buffer of the callback.
   // Interleaved.
-  nsTArray<AudioDataValue> mRecordedOutput;
+  nsTArray<AudioDataValue> mRecordedOutput MOZ_GUARDED_BY(mMutex);
   // The recorded data, copied from the input buffer of the callback.
   // Interleaved.
-  nsTArray<AudioDataValue> mRecordedInput;
+  nsTArray<AudioDataValue> mRecordedInput MOZ_GUARDED_BY(mMutex);
 };
 
+inline std::ostream& operator<<(std::ostream& aStream,
+                                const MockCubebStream::KeepProcessing& aVal) {
+  switch (aVal) {
+    case MockCubebStream::KeepProcessing::Yes:
+      aStream << "KeepProcessing::Yes";
+      return aStream;
+    case MockCubebStream::KeepProcessing::No:
+      aStream << "KeepProcessing::No";
+      return aStream;
+    case MockCubebStream::KeepProcessing::InvalidState:
+      aStream << "KeepProcessing::InvalidState";
+      return aStream;
+  }
+  aStream << "KeepProcessing(invalid " << static_cast<uint32_t>(aVal) << ")";
+  return aStream;
+}
+
 class SmartMockCubebStream
     : public MockCubebStream,
       public SupportsThreadSafeWeakPtr<SmartMockCubebStream> {
@@ -362,6 +405,16 @@ class MockCubeb {
       cubeb_device_type aDevType,
       cubeb_device_collection_changed_callback aCallback, void* aUserPtr);
 
+  Result<cubeb_input_processing_params, int> SupportedInputProcessingParams()
+      const;
+  void SetSupportedInputProcessingParams(cubeb_input_processing_params aParams,
+                                         int aRv);
+  // Set the rv to be returned when SetInputProcessingParams for any stream of
+  // this context would apply the params to the stream, i.e. after passing the
+  // supported-params check.
+  void SetInputProcessingApplyRv(int aRv);
+  int InputProcessingApplyRv() const;
+
   // Control API
 
   // Add an input or output device to this backend. This calls the device
@@ -455,6 +508,10 @@ class MockCubeb {
   // notification via a system callback. If not, Gecko is expected to re-query
   // the list every time.
   bool mSupportsDeviceCollectionChangedCallback = true;
+  std::pair<cubeb_input_processing_params, int>
+      mSupportedInputProcessingParams = std::make_pair(
+          CUBEB_INPUT_PROCESSING_PARAM_NONE, CUBEB_ERROR_NOT_SUPPORTED);
+  int mInputProcessingParamsApplyRv = CUBEB_OK;
   const RunningMode mRunningMode;
   Atomic<bool> mStreamInitErrorState;
   // Whether new MockCubebStreams should be frozen on start.
@@ -502,6 +559,18 @@ int cubeb_mock_register_device_collection_changed(
       devtype, callback, user_ptr);
 }
 
+int cubeb_mock_get_supported_input_processing_params(
+    cubeb* context, cubeb_input_processing_params* params) {
+  Result<cubeb_input_processing_params, int> res =
+      MockCubeb::AsMock(context)->SupportedInputProcessingParams();
+  if (res.isErr()) {
+    *params = CUBEB_INPUT_PROCESSING_PARAM_NONE;
+    return res.unwrapErr();
+  }
+  *params = res.unwrap();
+  return CUBEB_OK;
+}
+
 int cubeb_mock_stream_init(
     cubeb* context, cubeb_stream** stream, char const* stream_name,
     cubeb_devid input_device, cubeb_stream_params* input_stream_params,
@@ -562,6 +631,11 @@ int cubeb_mock_stream_register_device_changed_callback(
       device_changed_callback);
 }
 
+static int cubeb_mock_stream_set_input_processing_params(
+    cubeb_stream* stream, cubeb_input_processing_params params) {
+  return MockCubebStream::AsMock(stream)->SetInputProcessingParams(params);
+}
+
 int cubeb_mock_get_min_latency(cubeb* context, cubeb_stream_params params,
                                uint32_t* latency_ms) {
   *latency_ms = 10;
diff --git a/dom/media/gtest/TestAudioCallbackDriver.cpp b/dom/media/gtest/TestAudioCallbackDriver.cpp
index 050395fa44..9c8c9bd107 100644
--- a/dom/media/gtest/TestAudioCallbackDriver.cpp
+++ b/dom/media/gtest/TestAudioCallbackDriver.cpp
@@ -9,34 +9,39 @@
 #include "GraphDriver.h"
 
 #include "gmock/gmock.h"
-#include "gtest/gtest-printers.h"
 #include "gtest/gtest.h"
 
 #include "MediaTrackGraphImpl.h"
 #include "mozilla/gtest/WaitFor.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/SyncRunnable.h"
-#include "mozilla/UniquePtr.h"
 #include "nsTArray.h"
 
 #include "MockCubeb.h"
 
-using namespace mozilla;
+namespace mozilla {
+
 using IterationResult = GraphInterface::IterationResult;
 using ::testing::_;
 using ::testing::AnyNumber;
+using ::testing::AtMost;
+using ::testing::Eq;
+using ::testing::InSequence;
 using ::testing::NiceMock;
 
 class MockGraphInterface : public GraphInterface {
   NS_DECL_THREADSAFE_ISUPPORTS
   explicit MockGraphInterface(TrackRate aSampleRate)
       : mSampleRate(aSampleRate) {}
-  MOCK_METHOD0(NotifyInputStopped, void());
-  MOCK_METHOD5(NotifyInputData, void(const AudioDataValue*, size_t, TrackRate,
-                                     uint32_t, uint32_t));
-  MOCK_METHOD0(DeviceChanged, void());
+  MOCK_METHOD(void, NotifyInputStopped, ());
+  MOCK_METHOD(void, NotifyInputData,
+              (const AudioDataValue*, size_t, TrackRate, uint32_t, uint32_t));
+  MOCK_METHOD(void, NotifySetRequestedInputProcessingParamsResult,
+              (AudioCallbackDriver*, cubeb_input_processing_params,
+               (Result<cubeb_input_processing_params, int>&&)));
+  MOCK_METHOD(void, DeviceChanged, ());
 #ifdef DEBUG
-  MOCK_CONST_METHOD1(InDriverIteration, bool(const GraphDriver*));
+  MOCK_METHOD(bool, InDriverIteration, (const GraphDriver*), (const));
 #endif
   /* OneIteration cannot be mocked because IterationResult is non-memmovable and
    * cannot be passed as a parameter, which GMock does internally. */
@@ -81,7 +86,7 @@ class MockGraphInterface : public GraphInterface {
                 RefPtr<Runnable> aSwitchedRunnable = NS_NewRunnableFunction(
                     "DefaultNoopSwitchedRunnable", [] {})) {
     auto guard = mNextDriver.Lock();
-    MOZ_ASSERT(guard->isNothing());
+    MOZ_RELEASE_ASSERT(guard->isNothing());
     *guard =
         Some(std::make_tuple(std::move(aDriver), std::move(aSwitchedRunnable)));
   }
@@ -108,7 +113,7 @@ class MockGraphInterface : public GraphInterface {
 NS_IMPL_ISUPPORTS0(MockGraphInterface)
 
 TEST(TestAudioCallbackDriver, StartStop)
-MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
+MOZ_CAN_RUN_SCRIPT_BOUNDARY {
   const TrackRate rate = 44100;
   MockCubeb* cubeb = new MockCubeb();
   CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
@@ -118,7 +123,8 @@ MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
   EXPECT_CALL(*graph, NotifyInputStopped).Times(0);
 
   driver = MakeRefPtr<AudioCallbackDriver>(graph, nullptr, rate, 2, 0, nullptr,
-                                           nullptr, AudioInputType::Unknown);
+                                           nullptr, AudioInputType::Unknown,
+                                           CUBEB_INPUT_PROCESSING_PARAM_NONE);
   EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
   EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
 
@@ -135,7 +141,7 @@ MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
   EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
 }
 
-void TestSlowStart(const TrackRate aRate) MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
+void TestSlowStart(const TrackRate aRate) MOZ_CAN_RUN_SCRIPT_BOUNDARY {
   std::cerr << "TestSlowStart with rate " << aRate << std::endl;
 
   MockCubeb* cubeb = new MockCubeb();
@@ -177,15 +183,17 @@ void TestSlowStart(const TrackRate aRate) MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
       });
 
   driver = MakeRefPtr<AudioCallbackDriver>(graph, nullptr, aRate, 2, 2, nullptr,
-                                           (void*)1, AudioInputType::Voice);
+                                           (void*)1, AudioInputType::Voice,
+                                           CUBEB_INPUT_PROCESSING_PARAM_NONE);
   EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
   EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
 
   graph->SetCurrentDriver(driver);
   graph->SetEnsureNextIteration(true);
 
+  auto initPromise = TakeN(cubeb->StreamInitEvent(), 1);
   driver->Start();
-  RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
+  auto [stream] = WaitFor(initPromise).unwrap()[0];
   cubeb->SetStreamStartFreezeEnabled(false);
 
   const size_t fallbackIterations = 3;
@@ -234,7 +242,7 @@ void TestSlowStart(const TrackRate aRate) MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
 }
 
 TEST(TestAudioCallbackDriver, SlowStart)
-MOZ_CAN_RUN_SCRIPT_FOR_DEFINITION {
+{
   TestSlowStart(1000);   // 10ms = 10 <<< 128 samples
   TestSlowStart(8000);   // 10ms = 80  <  128 samples
   TestSlowStart(44100);  // 10ms = 441 >  128 samples
@@ -252,7 +260,7 @@ class MOZ_STACK_CLASS AutoSetter {
       : mVal(aVal), mNew(aNew), mOld(mVal.exchange(aNew)) {}
   ~AutoSetter() {
     DebugOnly<T> oldNew = mVal.exchange(mOld);
-    MOZ_ASSERT(oldNew == mNew);
+    MOZ_RELEASE_ASSERT(oldNew == mNew);
   }
 };
 #endif
@@ -265,12 +273,13 @@ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
 
   auto graph = MakeRefPtr<MockGraphInterface>(rate);
   auto driver = MakeRefPtr<AudioCallbackDriver>(
-      graph, nullptr, rate, 2, 1, nullptr, (void*)1, AudioInputType::Voice);
+      graph, nullptr, rate, 2, 1, nullptr, (void*)1, AudioInputType::Voice,
+      CUBEB_INPUT_PROCESSING_PARAM_NONE);
   EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
   EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
 
 #ifdef DEBUG
-  std::atomic<std::thread::id> threadInDriverIteration((std::thread::id()));
+  std::atomic<std::thread::id> threadInDriverIteration{std::thread::id()};
   EXPECT_CALL(*graph, InDriverIteration(driver.get())).WillRepeatedly([&] {
     return std::this_thread::get_id() == threadInDriverIteration;
   });
@@ -279,17 +288,24 @@ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
   EXPECT_CALL(*graph, NotifyInputData(_, 0, rate, 1, _)).Times(AnyNumber());
   EXPECT_CALL(*graph, NotifyInputData(_, ignoredFrameCount, _, _, _)).Times(0);
   EXPECT_CALL(*graph, DeviceChanged);
+  Result<cubeb_input_processing_params, int> expected =
+      Err(CUBEB_ERROR_NOT_SUPPORTED);
+  EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                          driver.get(), CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                          Eq(std::ref(expected))));
 
   graph->SetCurrentDriver(driver);
   graph->SetEnsureNextIteration(true);
   // This starts the fallback driver.
+  auto initPromise = TakeN(cubeb->StreamInitEvent(), 1);
   driver->Start();
-  RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
+  auto [stream] = WaitFor(initPromise).unwrap()[0];
 
   // Wait for the audio driver to have started the stream before running data
   // callbacks. driver->Start() does a dispatch to the cubeb operation thread
   // and starts the stream there.
-  nsCOMPtr<nsIEventTarget> cubebOpThread = CUBEB_TASK_THREAD;
+  nsCOMPtr<nsIEventTarget> cubebOpThread =
+      CubebUtils::GetCubebOperationThread();
   MOZ_ALWAYS_SUCCEEDS(SyncRunnable::DispatchToThread(
       cubebOpThread, NS_NewRunnableFunction(__func__, [] {})));
 
@@ -393,85 +409,412 @@ MOZ_CAN_RUN_SCRIPT_BOUNDARY {
 
   auto graph = MakeRefPtr<MockGraphInterface>(rate);
   auto driver = MakeRefPtr<AudioCallbackDriver>(
-      graph, nullptr, rate, 2, 1, nullptr, (void*)1, AudioInputType::Voice);
+      graph, nullptr, rate, 2, 1, nullptr, (void*)1, AudioInputType::Voice,
+      CUBEB_INPUT_PROCESSING_PARAM_NONE);
   EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
   EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
 
   auto newDriver = MakeRefPtr<AudioCallbackDriver>(
-      graph, nullptr, rate, 2, 1, nullptr, (void*)1, AudioInputType::Voice);
+      graph, nullptr, rate, 2, 1, nullptr, (void*)1, AudioInputType::Voice,
+      CUBEB_INPUT_PROCESSING_PARAM_NONE);
   EXPECT_FALSE(newDriver->ThreadRunning()) << "Verify thread is not running";
   EXPECT_FALSE(newDriver->IsStarted()) << "Verify thread is not started";
 
 #ifdef DEBUG
-  std::atomic<std::thread::id> threadInDriverIteration(
-      (std::this_thread::get_id()));
+  std::atomic<std::thread::id> threadInDriverIteration{
+      std::this_thread::get_id()};
   EXPECT_CALL(*graph, InDriverIteration(_)).WillRepeatedly([&] {
     return std::this_thread::get_id() == threadInDriverIteration;
   });
 #endif
   EXPECT_CALL(*graph, NotifyInputData(_, 0, rate, 1, _)).Times(AnyNumber());
-  EXPECT_CALL(*graph, DeviceChanged);
+  // This only happens if the first fallback driver is stopped by the audio
+  // driver handover rather than the driver switch. It happens when the
+  // subsequent audio callback performs the switch.
+  EXPECT_CALL(*graph, NotifyInputStopped()).Times(AtMost(1));
+  Result<cubeb_input_processing_params, int> expected =
+      Err(CUBEB_ERROR_NOT_SUPPORTED);
+  EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                          driver.get(), CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                          Eq(std::ref(expected))));
+  EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                          newDriver.get(), CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                          Eq(std::ref(expected))));
 
   graph->SetCurrentDriver(driver);
   graph->SetEnsureNextIteration(true);
+  auto initPromise = TakeN(cubeb->StreamInitEvent(), 1);
   // This starts the fallback driver.
   driver->Start();
-  RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
+  RefPtr<SmartMockCubebStream> stream;
+  std::tie(stream) = WaitFor(initPromise).unwrap()[0];
 
   // Wait for the audio driver to have started or the DeviceChanged event will
   // be ignored. driver->Start() does a dispatch to the cubeb operation thread
   // and starts the stream there.
-  nsCOMPtr<nsIEventTarget> cubebOpThread = CUBEB_TASK_THREAD;
+  nsCOMPtr<nsIEventTarget> cubebOpThread =
+      CubebUtils::GetCubebOperationThread();
   MOZ_ALWAYS_SUCCEEDS(SyncRunnable::DispatchToThread(
       cubebOpThread, NS_NewRunnableFunction(__func__, [] {})));
 
-#ifdef DEBUG
-  AutoSetter as(threadInDriverIteration, std::this_thread::get_id());
-#endif
+  initPromise = TakeN(cubeb->StreamInitEvent(), 1);
+  Monitor mon(__func__);
+  bool canContinueToStartNextDriver = false;
+  bool continued = false;
 
   // This marks the audio driver as running.
   EXPECT_EQ(stream->ManualDataCallback(0),
             MockCubebStream::KeepProcessing::Yes);
 
-  // If a fallback driver callback happens between the audio callback above, and
-  // the SwitchTo below, the audio driver will perform the switch instead of the
-  // fallback since the fallback will have stopped. This test may therefore
-  // intermittently take different code paths.
-
-  // Stop the fallback driver by switching audio driver in the graph.
-  {
-    Monitor mon(__func__);
-    MonitorAutoLock lock(mon);
-    bool switched = false;
-    graph->SwitchTo(newDriver, NS_NewRunnableFunction(__func__, [&] {
-                      MonitorAutoLock lock(mon);
-                      switched = true;
-                      lock.Notify();
-                    }));
-    while (!switched) {
-      lock.Wait();
-    }
+  // To satisfy TSAN's lock-order-inversion checking we avoid locking stream's
+  // mMutex (by calling ManualDataCallback) under mon. The SwitchTo runnable
+  // below already locks mon under stream's mMutex.
+  MonitorAutoLock lock(mon);
+
+  // If a fallback driver callback happens between the audio callback
+  // above, and the SwitchTo below, the driver will enter
+  // `FallbackDriverState::None`, relying on the audio driver to
+  // iterate the graph, including performing the driver switch. This
+  // test may therefore intermittently take different code paths.
+  // Note however that the fallback driver runs every ~10ms while the
+  // time from the manual callback above to telling the mock graph to
+  // switch drivers below is much much shorter. The vast majority of
+  // test runs will exercise the intended code path.
+
+  // Make the fallback driver enter FallbackDriverState::Stopped by
+  // switching audio driver in the graph.
+  graph->SwitchTo(newDriver, NS_NewRunnableFunction(__func__, [&] {
+                    MonitorAutoLock lock(mon);
+                    // Block the fallback driver on its thread until
+                    // the test on main thread has finished testing
+                    // what it needs.
+                    while (!canContinueToStartNextDriver) {
+                      lock.Wait();
+                    }
+                    // Notify the test that it can take these
+                    // variables off the stack now.
+                    continued = true;
+                    lock.Notify();
+                  }));
+
+  // Wait for the fallback driver to stop running.
+  while (driver->OnFallback()) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
   }
 
-  {
+  if (driver->HasFallback()) {
+    // Driver entered FallbackDriverState::Stopped as desired.
+    // Proceed with a DeviceChangedCallback.
+
+    EXPECT_CALL(*graph, DeviceChanged);
+
+    {
 #ifdef DEBUG
-    AutoSetter as(threadInDriverIteration, std::thread::id());
+      AutoSetter as(threadInDriverIteration, std::thread::id());
 #endif
-    // After stopping the fallback driver, but before newDriver has stopped the
-    // old audio driver, fire a DeviceChanged event to ensure it is handled
-    // properly.
-    AudioCallbackDriver::DeviceChangedCallback_s(driver);
+      // After stopping the fallback driver, but before newDriver has
+      // stopped the old audio driver, fire a DeviceChanged event to
+      // ensure it is handled properly.
+      AudioCallbackDriver::DeviceChangedCallback_s(driver);
+    }
+
+    EXPECT_FALSE(driver->OnFallback())
+        << "DeviceChangedCallback after stopping must not start the "
+           "fallback driver again";
   }
 
+  // Iterate the audio driver on a background thread in case the fallback
+  // driver completed the handover to the audio driver before the switch
+  // above. Doing the switch would deadlock as the switch runnable waits on
+  // mon.
+  NS_DispatchBackgroundTask(NS_NewRunnableFunction(
+      "DeviceChangeAfterStop::postSwitchManualAudioCallback", [stream] {
+        // An audio callback after switching must tell the stream to stop.
+        EXPECT_EQ(stream->ManualDataCallback(0),
+                  MockCubebStream::KeepProcessing::No);
+      }));
+
+  // Unblock the fallback driver.
+  canContinueToStartNextDriver = true;
+  lock.Notify();
+
+  // Wait for the fallback driver to continue, so we can clear the
+  // stack.
+  while (!continued) {
+    lock.Wait();
+  }
+
+  // Wait for newDriver's cubeb stream to init.
+  std::tie(stream) = WaitFor(initPromise).unwrap()[0];
+
   graph->StopIterating();
   newDriver->EnsureNextIteration();
   while (newDriver->OnFallback()) {
     std::this_thread::sleep_for(std::chrono::milliseconds(1));
   }
 
-  // This will block until all events have been queued.
-  MOZ_KnownLive(driver)->Shutdown();
-  MOZ_KnownLive(newDriver)->Shutdown();
+  {
+#ifdef DEBUG
+    AutoSetter as(threadInDriverIteration, std::thread::id());
+#endif
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::No);
+  }
+
   // Drain the event queue.
   NS_ProcessPendingEvents(nullptr);
 }
+
+void TestInputProcessingOnStart(
+    MockCubeb* aCubeb, cubeb_input_processing_params aRequested,
+    const Result<cubeb_input_processing_params, int>& aExpected)
+    MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+  const TrackRate rate = 44100;
+
+  auto graph = MakeRefPtr<NiceMock<MockGraphInterface>>(rate);
+  auto driver = MakeRefPtr<AudioCallbackDriver>(
+      graph, nullptr, rate, 2, 1, nullptr, nullptr, AudioInputType::Voice,
+      aRequested);
+  EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
+  EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
+
+#ifdef DEBUG
+  std::atomic_bool inGraphIteration{false};
+  ON_CALL(*graph, InDriverIteration(_)).WillByDefault([&] {
+    return inGraphIteration.load() && NS_IsMainThread();
+  });
+#endif
+  bool notified = false;
+  EXPECT_CALL(*graph, NotifyInputStopped).Times(0);
+  EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                          driver.get(), aRequested, Eq(std::ref(aExpected))))
+      .WillOnce([&] { notified = true; });
+
+  graph->SetCurrentDriver(driver);
+  auto initPromise = TakeN(aCubeb->StreamInitEvent(), 1);
+  driver->Start();
+  auto [stream] = WaitFor(initPromise).unwrap()[0];
+
+  // Wait for the audio driver to have started the stream before running data
+  // callbacks. driver->Start() does a dispatch to the cubeb operation thread
+  // and starts the stream there.
+  nsCOMPtr<nsIEventTarget> cubebOpThread =
+      CubebUtils::GetCubebOperationThread();
+  MOZ_ALWAYS_SUCCEEDS(SyncRunnable::DispatchToThread(
+      cubebOpThread, NS_NewRunnableFunction(__func__, [] {})));
+
+  // This makes the fallback driver stop on its next callback.
+  {
+#ifdef DEBUG
+    AutoSetter as(inGraphIteration, true);
+#endif
+    while (driver->OnFallback()) {
+      stream->ManualDataCallback(0);
+      std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    }
+  }
+
+  while (!notified) {
+    NS_ProcessNextEvent();
+  }
+
+  // This will block untill all events have been executed.
+  MOZ_KnownLive(driver)->Shutdown();
+  EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
+  EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
+}
+
+TEST(TestAudioCallbackDriver, InputProcessingOnStart)
+{
+  constexpr cubeb_input_processing_params allParams =
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+      CUBEB_INPUT_PROCESSING_PARAM_AUTOMATIC_GAIN_CONTROL |
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION |
+      CUBEB_INPUT_PROCESSING_PARAM_VOICE_ISOLATION;
+
+  MockCubeb* cubeb = new MockCubeb(MockCubeb::RunningMode::Manual);
+  CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
+
+  // Not supported by backend.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_ERROR_NOT_SUPPORTED);
+  TestInputProcessingOnStart(cubeb,
+                             CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                             Err(CUBEB_ERROR_NOT_SUPPORTED));
+
+  // Not supported by params.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_OK);
+  TestInputProcessingOnStart(cubeb,
+                             CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                             CUBEB_INPUT_PROCESSING_PARAM_NONE);
+
+  // Successful all.
+  cubeb->SetSupportedInputProcessingParams(allParams, CUBEB_OK);
+  TestInputProcessingOnStart(cubeb, allParams, allParams);
+
+  // Successful partial.
+  TestInputProcessingOnStart(cubeb,
+                             CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                             CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+
+  // Not supported by stream.
+  cubeb->SetInputProcessingApplyRv(CUBEB_ERROR);
+  TestInputProcessingOnStart(
+      cubeb, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION, Err(CUBEB_ERROR));
+}
+
+TEST(TestAudioCallbackDriver, InputProcessingWhileRunning)
+MOZ_CAN_RUN_SCRIPT_BOUNDARY {
+  constexpr TrackRate rate = 44100;
+  constexpr cubeb_input_processing_params allParams =
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+      CUBEB_INPUT_PROCESSING_PARAM_AUTOMATIC_GAIN_CONTROL |
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION |
+      CUBEB_INPUT_PROCESSING_PARAM_VOICE_ISOLATION;
+  constexpr int applyError = 99;
+
+  int numNotifications = 0;
+  const auto signal = [&]() mutable {
+    MOZ_ASSERT(NS_IsMainThread());
+    ++numNotifications;
+  };
+  const auto waitForSignal = [&](int aNotification) {
+    while (numNotifications < aNotification) {
+      NS_ProcessNextEvent();
+    }
+  };
+  MockCubeb* cubeb = new MockCubeb(MockCubeb::RunningMode::Manual);
+  CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
+
+  auto graph = MakeRefPtr<NiceMock<MockGraphInterface>>(rate);
+  auto driver = MakeRefPtr<AudioCallbackDriver>(
+      graph, nullptr, rate, 2, 1, nullptr, nullptr, AudioInputType::Voice,
+      CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
+  EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
+
+  EXPECT_CALL(*graph, NotifyInputStopped).Times(0);
+  // Expectations
+  const Result<cubeb_input_processing_params, int> noneResult =
+      CUBEB_INPUT_PROCESSING_PARAM_NONE;
+  const Result<cubeb_input_processing_params, int> aecResult =
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION;
+  const Result<cubeb_input_processing_params, int> allResult = allParams;
+  const Result<cubeb_input_processing_params, int> notSupportedResult =
+      Err(CUBEB_ERROR_NOT_SUPPORTED);
+  const Result<cubeb_input_processing_params, int> applyErrorResult =
+      Err(applyError);
+  {
+    InSequence s;
+
+    // Notified on start.
+    EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                            driver.get(), CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                            Eq(std::ref(notSupportedResult))))
+        .WillOnce(signal);
+    // Not supported by backend.
+    EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                            driver.get(),
+                            CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION,
+                            Eq(std::ref(notSupportedResult))))
+        .WillOnce(signal);
+    // Not supported by params.
+    EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                            driver.get(),
+                            CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                            Eq(std::ref(noneResult))))
+        .WillOnce(signal);
+    // Successful all.
+    EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                            driver.get(), allParams, Eq(std::ref(allResult))))
+        .WillOnce(signal);
+    // Successful partial.
+    EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                            driver.get(),
+                            CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                            Eq(std::ref(aecResult))))
+        .WillOnce(signal);
+    // Not supported by stream.
+    EXPECT_CALL(*graph, NotifySetRequestedInputProcessingParamsResult(
+                            driver.get(),
+                            CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION,
+                            Eq(std::ref(applyErrorResult))))
+        .WillOnce(signal);
+  }
+
+#ifdef DEBUG
+  std::atomic_bool inGraphIteration{false};
+  ON_CALL(*graph, InDriverIteration(_)).WillByDefault([&] {
+    return inGraphIteration.load() && NS_IsMainThread();
+  });
+#endif
+
+  const auto setParams = [&](cubeb_input_processing_params aParams) {
+    {
+#ifdef DEBUG
+      AutoSetter as(inGraphIteration, true);
+#endif
+      driver->SetRequestedInputProcessingParams(aParams);
+    }
+  };
+
+  graph->SetCurrentDriver(driver);
+  auto initPromise = TakeN(cubeb->StreamInitEvent(), 1);
+  driver->Start();
+  auto [stream] = WaitFor(initPromise).unwrap()[0];
+
+  // Wait for the audio driver to have started the stream before running data
+  // callbacks. driver->Start() does a dispatch to the cubeb operation thread
+  // and starts the stream there.
+  nsCOMPtr<nsIEventTarget> cubebOpThread =
+      CubebUtils::GetCubebOperationThread();
+  MOZ_ALWAYS_SUCCEEDS(SyncRunnable::DispatchToThread(
+      cubebOpThread, NS_NewRunnableFunction(__func__, [] {})));
+
+  // This makes the fallback driver stop on its next callback.
+
+  {
+#ifdef DEBUG
+    AutoSetter as(inGraphIteration, true);
+#endif
+    while (driver->OnFallback()) {
+      stream->ManualDataCallback(0);
+      std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    }
+  }
+  waitForSignal(1);
+
+  // Not supported by backend.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_ERROR_NOT_SUPPORTED);
+  setParams(CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION);
+  waitForSignal(2);
+
+  // Not supported by params.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_OK);
+  setParams(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+  waitForSignal(3);
+
+  // Successful all.
+  cubeb->SetSupportedInputProcessingParams(allParams, CUBEB_OK);
+  setParams(allParams);
+  waitForSignal(4);
+
+  // Successful partial.
+  setParams(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+  waitForSignal(5);
+
+  // Not supported by stream.
+  cubeb->SetInputProcessingApplyRv(applyError);
+  setParams(CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION);
+  waitForSignal(6);
+
+  // This will block untill all events have been executed.
+  MOZ_KnownLive(driver)->Shutdown();
+  EXPECT_FALSE(driver->ThreadRunning()) << "Verify thread is not running";
+  EXPECT_FALSE(driver->IsStarted()) << "Verify thread is not started";
+}
+
+}  // namespace mozilla
diff --git a/dom/media/gtest/TestAudioInputProcessing.cpp b/dom/media/gtest/TestAudioInputProcessing.cpp
index d21c37a900..e357839768 100644
--- a/dom/media/gtest/TestAudioInputProcessing.cpp
+++ b/dom/media/gtest/TestAudioInputProcessing.cpp
@@ -428,3 +428,178 @@ TEST(TestAudioInputProcessing, Downmixing)
   aip->Stop(graph);
   track->Destroy();
 }
+
+TEST(TestAudioInputProcessing, DisabledPlatformProcessing)
+{
+  const TrackRate rate = 44100;
+  const uint32_t channels = 1;
+  auto graph = MakeRefPtr<NiceMock<MockGraph>>(rate);
+  graph->Init(channels);
+
+  auto aip = MakeRefPtr<AudioInputProcessing>(channels);
+
+  MediaEnginePrefs settings;
+  settings.mUsePlatformProcessing = false;
+  settings.mAecOn = true;
+  aip->ApplySettings(graph, nullptr, settings);
+  aip->Start(graph);
+
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_NONE);
+
+  aip->Stop(graph);
+  graph->Destroy();
+}
+
+TEST(TestAudioInputProcessing, EnabledPlatformProcessing)
+{
+  const TrackRate rate = 44100;
+  const uint32_t channels = 1;
+  auto graph = MakeRefPtr<NiceMock<MockGraph>>(rate);
+  graph->Init(channels);
+
+  auto aip = MakeRefPtr<AudioInputProcessing>(channels);
+
+  MediaEnginePrefs settings;
+  settings.mUsePlatformProcessing = true;
+  settings.mAecOn = true;
+  aip->ApplySettings(graph, nullptr, settings);
+  aip->Start(graph);
+
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+
+  aip->Stop(graph);
+  graph->Destroy();
+}
+
+namespace webrtc {
+bool operator==(const AudioProcessing::Config& aLhs,
+                const AudioProcessing::Config& aRhs) {
+  return aLhs.echo_canceller.enabled == aRhs.echo_canceller.enabled &&
+         (aLhs.gain_controller1.enabled == aRhs.gain_controller1.enabled ||
+          aLhs.gain_controller2.enabled == aRhs.gain_controller2.enabled) &&
+         aLhs.noise_suppression.enabled == aRhs.noise_suppression.enabled;
+}
+
+static std::ostream& operator<<(
+    std::ostream& aStream, const webrtc::AudioProcessing::Config& aConfig) {
+  aStream << "webrtc::AudioProcessing::Config[";
+  bool hadPrior = false;
+  if (aConfig.echo_canceller.enabled) {
+    aStream << "AEC";
+    hadPrior = true;
+  }
+  if (aConfig.gain_controller1.enabled || aConfig.gain_controller2.enabled) {
+    if (hadPrior) {
+      aStream << ", ";
+    }
+    aStream << "AGC";
+  }
+  if (aConfig.noise_suppression.enabled) {
+    if (hadPrior) {
+      aStream << ", ";
+    }
+    aStream << "NS";
+  }
+  aStream << "]";
+  return aStream;
+}
+}  // namespace webrtc
+
+TEST(TestAudioInputProcessing, PlatformProcessing)
+{
+  const TrackRate rate = 44100;
+  const uint32_t channels = 1;
+  auto graph = MakeRefPtr<NiceMock<MockGraph>>(rate);
+  graph->Init(channels);
+
+  auto aip = MakeRefPtr<AudioInputProcessing>(channels);
+
+  MediaEnginePrefs settings;
+  settings.mUsePlatformProcessing = true;
+  settings.mAecOn = true;
+  aip->ApplySettings(graph, nullptr, settings);
+  aip->Start(graph);
+
+  webrtc::AudioProcessing::Config echoOnlyConfig;
+  echoOnlyConfig.echo_canceller.enabled = true;
+  webrtc::AudioProcessing::Config echoNoiseConfig = echoOnlyConfig;
+  echoNoiseConfig.noise_suppression.enabled = true;
+
+  // Config is applied, and platform processing requested.
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+  EXPECT_EQ(aip->AppliedConfig(graph), echoOnlyConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+
+  // Platform processing params successfully applied.
+  aip->NotifySetRequestedInputProcessingParamsResult(
+      graph, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+  // Turns off the equivalent APM config.
+  EXPECT_EQ(aip->AppliedConfig(graph), webrtc::AudioProcessing::Config());
+  EXPECT_TRUE(aip->IsPassThrough(graph));
+
+  // Simulate an error after a driver switch.
+  aip->NotifySetRequestedInputProcessingParamsResult(
+      graph, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION, Err(CUBEB_ERROR));
+  // The APM config is turned back on, and platform processing is requested to
+  // be turned off.
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  EXPECT_EQ(aip->AppliedConfig(graph), echoOnlyConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+
+  // Pretend there was a response for an old request.
+  aip->NotifySetRequestedInputProcessingParamsResult(
+      graph, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+  // It does nothing since we are requesting NONE now.
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  EXPECT_EQ(aip->AppliedConfig(graph), echoOnlyConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+
+  // Turn it off as requested.
+  aip->NotifySetRequestedInputProcessingParamsResult(
+      graph, CUBEB_INPUT_PROCESSING_PARAM_NONE,
+      CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  EXPECT_EQ(aip->AppliedConfig(graph), echoOnlyConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+
+  // Test partial support for the requested params.
+  settings.mNoiseOn = true;
+  aip->ApplySettings(graph, nullptr, settings);
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+                CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION);
+  EXPECT_EQ(aip->AppliedConfig(graph), echoNoiseConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+  // Only noise suppression was supported in the platform.
+  aip->NotifySetRequestedInputProcessingParamsResult(
+      graph,
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+          CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION,
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION);
+  // In the APM only echo cancellation is applied.
+  EXPECT_EQ(aip->AppliedConfig(graph), echoOnlyConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+
+  // Test error for partial support.
+  aip->NotifySetRequestedInputProcessingParamsResult(
+      graph,
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+          CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION,
+      Err(CUBEB_ERROR));
+  // The full config is applied in the APM, and NONE is requested.
+  EXPECT_EQ(aip->RequestedInputProcessingParams(graph),
+            CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  EXPECT_EQ(aip->AppliedConfig(graph), echoNoiseConfig);
+  EXPECT_FALSE(aip->IsPassThrough(graph));
+
+  aip->Stop(graph);
+  graph->Destroy();
+}
diff --git a/dom/media/gtest/TestAudioInputSource.cpp b/dom/media/gtest/TestAudioInputSource.cpp
index f3f18b26a9..5defd1d053 100644
--- a/dom/media/gtest/TestAudioInputSource.cpp
+++ b/dom/media/gtest/TestAudioInputSource.cpp
@@ -10,16 +10,22 @@
 #include "gtest/gtest.h"
 
 #include "MockCubeb.h"
+#include "mozilla/Result.h"
 #include "mozilla/gtest/WaitFor.h"
 #include "nsContentUtils.h"
 
 using namespace mozilla;
 using testing::ContainerEq;
 
-namespace {
+// Short-hand for DispatchToCurrentThread with a function.
 #define DispatchFunction(f) \
   NS_DispatchToCurrentThread(NS_NewRunnableFunction(__func__, f))
-}  // namespace
+
+// Short-hand for draining the current threads event queue, i.e. processing
+// those runnables dispatched per above.
+#define ProcessEventQueue()                     \
+  while (NS_ProcessNextEvent(nullptr, false)) { \
+  }
 
 class MockEventListener : public AudioInputSource::EventListener {
  public:
@@ -63,7 +69,10 @@ TEST(TestAudioInputSource, StartAndStop)
 
   // Make sure start and stop works.
   {
-    DispatchFunction([&] { ais->Start(); });
+    DispatchFunction([&] {
+      ais->Init();
+      ais->Start();
+    });
     RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
     EXPECT_TRUE(stream->mHasInput);
     EXPECT_FALSE(stream->mHasOutput);
@@ -79,7 +88,10 @@ TEST(TestAudioInputSource, StartAndStop)
 
   // Make sure restart is ok.
   {
-    DispatchFunction([&] { ais->Start(); });
+    DispatchFunction([&] {
+      ais->Init();
+      ais->Start();
+    });
     RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
     EXPECT_TRUE(stream->mHasInput);
     EXPECT_FALSE(stream->mHasOutput);
@@ -133,7 +145,10 @@ TEST(TestAudioInputSource, DataOutputBeforeStartAndAfterStop)
     EXPECT_TRUE(data.IsNull());
   }
 
-  DispatchFunction([&] { ais->Start(); });
+  DispatchFunction([&] {
+    ais->Init();
+    ais->Start();
+  });
   RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream->mHasInput);
   EXPECT_FALSE(stream->mHasOutput);
@@ -206,7 +221,10 @@ TEST(TestAudioInputSource, ErrorCallback)
       sourceRate, targetRate);
   ASSERT_TRUE(ais);
 
-  DispatchFunction([&] { ais->Start(); });
+  DispatchFunction([&] {
+    ais->Init();
+    ais->Start();
+  });
   RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream->mHasInput);
   EXPECT_FALSE(stream->mHasOutput);
@@ -251,7 +269,10 @@ TEST(TestAudioInputSource, DeviceChangedCallback)
       sourceRate, targetRate);
   ASSERT_TRUE(ais);
 
-  DispatchFunction([&] { ais->Start(); });
+  DispatchFunction([&] {
+    ais->Init();
+    ais->Start();
+  });
   RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream->mHasInput);
   EXPECT_FALSE(stream->mHasOutput);
@@ -267,3 +288,82 @@ TEST(TestAudioInputSource, DeviceChangedCallback)
 
   ais = nullptr;  // Drop the SharedThreadPool here.
 }
+
+TEST(TestAudioInputSource, InputProcessing)
+{
+  MockCubeb* cubeb = new MockCubeb();
+  CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
+
+  const AudioInputSource::Id sourceId = 1;
+  const CubebUtils::AudioDeviceID deviceId = (CubebUtils::AudioDeviceID)1;
+  const uint32_t channels = 2;
+  const PrincipalHandle testPrincipal =
+      MakePrincipalHandle(nsContentUtils::GetSystemPrincipal());
+  const TrackRate sourceRate = 44100;
+  const TrackRate targetRate = 48000;
+  using ProcessingPromise =
+      AudioInputSource::SetRequestedProcessingParamsPromise;
+
+  auto listener = MakeRefPtr<MockEventListener>();
+  EXPECT_CALL(*listener,
+              AudioStateCallback(
+                  sourceId, AudioInputSource::EventListener::State::Started))
+      .Times(0);
+  EXPECT_CALL(*listener,
+              AudioStateCallback(
+                  sourceId, AudioInputSource::EventListener::State::Stopped))
+      .Times(10);
+
+  RefPtr<AudioInputSource> ais = MakeRefPtr<AudioInputSource>(
+      std::move(listener), sourceId, deviceId, channels, true, testPrincipal,
+      sourceRate, targetRate);
+
+  const auto test =
+      [&](cubeb_input_processing_params aRequested,
+          const Result<cubeb_input_processing_params, int>& aExpected) {
+        RefPtr<ProcessingPromise> p;
+        DispatchFunction([&] {
+          ais->Init();
+          p = ais->SetRequestedProcessingParams(aRequested);
+        });
+        ProcessEventQueue();
+        EXPECT_EQ(WaitFor(p), aExpected);
+
+        DispatchFunction([&] { ais->Stop(); });
+        Unused << WaitFor(cubeb->StreamDestroyEvent());
+      };
+
+  // Not supported by backend.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_ERROR_NOT_SUPPORTED);
+  test(CUBEB_INPUT_PROCESSING_PARAM_NONE, Err(CUBEB_ERROR_NOT_SUPPORTED));
+
+  // Not supported by params.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_OK);
+  test(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+       CUBEB_INPUT_PROCESSING_PARAM_NONE);
+
+  constexpr cubeb_input_processing_params allParams =
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION |
+      CUBEB_INPUT_PROCESSING_PARAM_AUTOMATIC_GAIN_CONTROL |
+      CUBEB_INPUT_PROCESSING_PARAM_VOICE_ISOLATION;
+
+  // Successful all.
+  cubeb->SetSupportedInputProcessingParams(allParams, CUBEB_OK);
+  test(allParams, allParams);
+
+  // Successful partial.
+  test(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+       CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+
+  // Not supported by stream.
+  // Note this also tests that AudioInputSource resets its configured params
+  // state from the previous successful test.
+  constexpr int propagatedError = 99;
+  cubeb->SetInputProcessingApplyRv(propagatedError);
+  test(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION, Err(propagatedError));
+
+  ais = nullptr;  // Drop the SharedThreadPool here.
+}
diff --git a/dom/media/gtest/TestAudioRingBuffer.cpp b/dom/media/gtest/TestAudioRingBuffer.cpp
index 082323efd1..3da39780f1 100644
--- a/dom/media/gtest/TestAudioRingBuffer.cpp
+++ b/dom/media/gtest/TestAudioRingBuffer.cpp
@@ -1094,7 +1094,7 @@ TEST(TestAudioRingBuffer, PrependSilenceNoWrapShort)
   EXPECT_THAT(out, ElementsAre(2, 3, 4, 5, 0, 0, 6, 7));
 }
 
-TEST(TestAudioRingBuffer, SetLengthBytesNoWrapFloat)
+TEST(TestAudioRingBuffer, EnsureLengthBytesNoWrapFloat)
 {
   AudioRingBuffer rb(6 * sizeof(float));
   rb.SetSampleFormat(AUDIO_FORMAT_FLOAT32);
@@ -1106,7 +1106,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesNoWrapFloat)
   EXPECT_EQ(rb.AvailableWrite(), 0u);
   EXPECT_EQ(rb.Capacity(), 6u);
 
-  EXPECT_TRUE(rb.SetLengthBytes(11 * sizeof(float)));
+  EXPECT_TRUE(rb.EnsureLengthBytes(11 * sizeof(float)));
   float out[10] = {};
   rv = rb.Read(Span(out, 10));
   EXPECT_EQ(rv, 5u);
@@ -1116,7 +1116,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesNoWrapFloat)
   EXPECT_THAT(out, ElementsAre(.1, .2, .3, .4, .5, 0, 0, 0, 0, 0));
 }
 
-TEST(TestAudioRingBuffer, SetLengthBytesNoWrapShort)
+TEST(TestAudioRingBuffer, EnsureLengthBytesNoWrapShort)
 {
   AudioRingBuffer rb(6 * sizeof(short));
   rb.SetSampleFormat(AUDIO_FORMAT_S16);
@@ -1128,7 +1128,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesNoWrapShort)
   EXPECT_EQ(rb.AvailableWrite(), 0u);
   EXPECT_EQ(rb.Capacity(), 6u);
 
-  EXPECT_TRUE(rb.SetLengthBytes(11 * sizeof(short)));
+  EXPECT_TRUE(rb.EnsureLengthBytes(11 * sizeof(short)));
   short out[10] = {};
   rv = rb.Read(Span(out, 10));
   EXPECT_EQ(rv, 5u);
@@ -1138,7 +1138,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesNoWrapShort)
   EXPECT_THAT(out, ElementsAre(1, 2, 3, 4, 5, 0, 0, 0, 0, 0));
 }
 
-TEST(TestAudioRingBuffer, SetLengthBytesWrap1PartFloat)
+TEST(TestAudioRingBuffer, EnsureLengthBytesWrap1PartFloat)
 {
   AudioRingBuffer rb(6 * sizeof(float));
   rb.SetSampleFormat(AUDIO_FORMAT_FLOAT32);
@@ -1158,7 +1158,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap1PartFloat)
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 0u);
 
-  EXPECT_TRUE(rb.SetLengthBytes(11 * sizeof(float)));
+  EXPECT_TRUE(rb.EnsureLengthBytes(11 * sizeof(float)));
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 5u);
 
@@ -1175,7 +1175,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap1PartFloat)
   EXPECT_THAT(out, ElementsAre(.1, .2, .3, .4, .5, .6, .7, 0, 0, 0));
 }
 
-TEST(TestAudioRingBuffer, SetLengthBytesWrap1PartShort)
+TEST(TestAudioRingBuffer, EnsureLengthBytesWrap1PartShort)
 {
   AudioRingBuffer rb(6 * sizeof(short));
   rb.SetSampleFormat(AUDIO_FORMAT_S16);
@@ -1195,7 +1195,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap1PartShort)
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 0u);
 
-  EXPECT_TRUE(rb.SetLengthBytes(11 * sizeof(short)));
+  EXPECT_TRUE(rb.EnsureLengthBytes(11 * sizeof(short)));
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 5u);
 
@@ -1212,7 +1212,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap1PartShort)
   EXPECT_THAT(out, ElementsAre(1, 2, 3, 4, 5, 6, 7, 0, 0, 0));
 }
 
-TEST(TestAudioRingBuffer, SetLengthBytesWrap2PartsFloat)
+TEST(TestAudioRingBuffer, EnsureLengthBytesWrap2PartsFloat)
 {
   AudioRingBuffer rb(6 * sizeof(float));
   rb.SetSampleFormat(AUDIO_FORMAT_FLOAT32);
@@ -1232,7 +1232,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap2PartsFloat)
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 0u);
 
-  EXPECT_TRUE(rb.SetLengthBytes(8 * sizeof(float)));
+  EXPECT_TRUE(rb.EnsureLengthBytes(8 * sizeof(float)));
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 2u);
 
@@ -1249,7 +1249,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap2PartsFloat)
   EXPECT_THAT(out, ElementsAre(.1, .2, .3, .4, .5, .6, .7, 0));
 }
 
-TEST(TestAudioRingBuffer, SetLengthBytesWrap2PartsShort)
+TEST(TestAudioRingBuffer, EnsureLengthBytesWrap2PartsShort)
 {
   AudioRingBuffer rb(6 * sizeof(short));
   rb.SetSampleFormat(AUDIO_FORMAT_S16);
@@ -1269,7 +1269,7 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap2PartsShort)
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 0u);
 
-  EXPECT_TRUE(rb.SetLengthBytes(8 * sizeof(short)));
+  EXPECT_TRUE(rb.EnsureLengthBytes(8 * sizeof(short)));
   EXPECT_EQ(rb.AvailableRead(), 5u);
   EXPECT_EQ(rb.AvailableWrite(), 2u);
 
@@ -1285,3 +1285,29 @@ TEST(TestAudioRingBuffer, SetLengthBytesWrap2PartsShort)
   EXPECT_EQ(rb.Capacity(), 8u);
   EXPECT_THAT(out, ElementsAre(1, 2, 3, 4, 5, 6, 7, 0));
 }
+
+TEST(TestAudioRingBuffer, EnsureLengthShorter)
+{
+  AudioRingBuffer rb(5 * sizeof(float));
+  rb.SetSampleFormat(AUDIO_FORMAT_FLOAT32);
+
+  float in[5] = {.1, .2, .3, .4, .5};
+  EXPECT_EQ(rb.Write(Span(in, 5)), 4u);
+  EXPECT_EQ(rb.AvailableRead(), 4u);
+  EXPECT_EQ(rb.AvailableWrite(), 0u);
+  EXPECT_EQ(rb.Capacity(), 5u);
+
+  float out[5] = {};
+  EXPECT_EQ(rb.Read(Span(out, 3)), 3u);
+  EXPECT_THAT(out, ElementsAre(.1, .2, .3, 0, 0));
+  EXPECT_EQ(rb.AvailableRead(), 1u);
+  EXPECT_EQ(rb.AvailableWrite(), 3u);
+
+  EXPECT_TRUE(rb.EnsureLengthBytes(3 * sizeof(float)));
+  EXPECT_EQ(rb.AvailableRead(), 1u);
+  EXPECT_EQ(rb.AvailableWrite(), 3u);
+  EXPECT_EQ(rb.Capacity(), 5u);
+  EXPECT_EQ(rb.Write(Span(in, 5)), 3u);
+  EXPECT_EQ(rb.Read(Span(out, 5)), 4u);
+  EXPECT_THAT(out, ElementsAre(.4, .1, .2, .3, 0));
+}
diff --git a/dom/media/gtest/TestAudioTrackGraph.cpp b/dom/media/gtest/TestAudioTrackGraph.cpp
index 7be1224ab9..b1202277ce 100644
--- a/dom/media/gtest/TestAudioTrackGraph.cpp
+++ b/dom/media/gtest/TestAudioTrackGraph.cpp
@@ -21,9 +21,13 @@
 #include "WavDumper.h"
 
 using namespace mozilla;
+using testing::Eq;
+using testing::InSequence;
+using testing::Return;
+using testing::StrictMock;
 
 // Short-hand for InvokeAsync on the current thread.
-#define Invoke(f) InvokeAsync(GetCurrentSerialEventTarget(), __func__, f)
+#define InvokeAsync(f) InvokeAsync(GetCurrentSerialEventTarget(), __func__, f)
 
 // Short-hand for DispatchToCurrentThread with a function.
 #define DispatchFunction(f) \
@@ -33,6 +37,12 @@ using namespace mozilla;
 #define DispatchMethod(t, m, args...) \
   NS_DispatchToCurrentThread(NewRunnableMethod(__func__, t, m, ##args))
 
+// Short-hand for draining the current threads event queue, i.e. processing
+// those runnables dispatched per above.
+#define ProcessEventQueue()                     \
+  while (NS_ProcessNextEvent(nullptr, false)) { \
+  }
+
 namespace {
 #ifdef MOZ_WEBRTC
 /*
@@ -111,6 +121,44 @@ struct StopNonNativeInput : public ControlMessage {
   void Run() override { mInputTrack->StopAudio(); }
 };
 
+// Helper for detecting when fallback driver has been switched away, for use
+// with RunningMode::Manual.
+class OnFallbackListener : public MediaTrackListener {
+  const RefPtr<MediaTrack> mTrack;
+  Atomic<bool> mOnFallback{true};
+
+ public:
+  explicit OnFallbackListener(MediaTrack* aTrack) : mTrack(aTrack) {}
+
+  void Reset() { mOnFallback = true; }
+  bool OnFallback() { return mOnFallback; }
+
+  void NotifyOutput(MediaTrackGraph*, TrackTime) override {
+    if (auto* ad =
+            mTrack->GraphImpl()->CurrentDriver()->AsAudioCallbackDriver()) {
+      mOnFallback = ad->OnFallback();
+    }
+  }
+};
+
+class MockAudioDataListener : public AudioDataListener {
+ protected:
+  ~MockAudioDataListener() = default;
+
+ public:
+  MockAudioDataListener() = default;
+
+  MOCK_METHOD(uint32_t, RequestedInputChannelCount, (MediaTrackGraph*),
+              (const));
+  MOCK_METHOD(cubeb_input_processing_params, RequestedInputProcessingParams,
+              (MediaTrackGraph*), (const));
+  MOCK_METHOD(bool, IsVoiceInput, (MediaTrackGraph*), (const));
+  MOCK_METHOD(void, DeviceChanged, (MediaTrackGraph*));
+  MOCK_METHOD(void, Disconnect, (MediaTrackGraph*));
+  MOCK_METHOD(void, NotifySetRequestedInputProcessingParamsResult,
+              (MediaTrackGraph*, cubeb_input_processing_params,
+               (const Result<cubeb_input_processing_params, int>&)));
+};
 }  // namespace
 
 /*
@@ -164,7 +212,7 @@ TEST(TestAudioTrackGraph, DifferentDeviceIDs)
     // graph from the global hash table and let it shutdown.
 
     using SourceTrackPromise = MozPromise<SourceMediaTrack*, nsresult, true>;
-    auto p = Invoke([g] {
+    auto p = InvokeAsync([g] {
       return SourceTrackPromise::CreateAndResolve(
           g->CreateSourceTrack(MediaSegment::AUDIO), __func__);
     });
@@ -256,7 +304,7 @@ TEST(TestAudioTrackGraph, NotifyDeviceStarted)
       nullptr, GetMainThreadSerialEventTarget());
 
   RefPtr<SourceMediaTrack> dummySource;
-  Unused << WaitFor(Invoke([&] {
+  Unused << WaitFor(InvokeAsync([&] {
     // Dummy track to make graph rolling. Add it and remove it to remove the
     // graph from the global hash table and let it shutdown.
     dummySource = graph->CreateSourceTrack(MediaSegment::AUDIO);
@@ -522,7 +570,7 @@ TEST(TestAudioTrackGraph, NonNativeInputTrackErrorCallback)
 class TestDeviceInputConsumerTrack : public DeviceInputConsumerTrack {
  public:
   static TestDeviceInputConsumerTrack* Create(MediaTrackGraph* aGraph) {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     TestDeviceInputConsumerTrack* track =
         new TestDeviceInputConsumerTrack(aGraph->GraphRate());
     aGraph->AddTrack(track);
@@ -530,7 +578,7 @@ class TestDeviceInputConsumerTrack : public DeviceInputConsumerTrack {
   }
 
   void Destroy() {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     DisconnectDeviceInput();
     DeviceInputConsumerTrack::Destroy();
   }
@@ -543,7 +591,7 @@ class TestDeviceInputConsumerTrack : public DeviceInputConsumerTrack {
     if (mInputs.IsEmpty()) {
       GetData<AudioSegment>()->AppendNullData(aTo - aFrom);
     } else {
-      MOZ_ASSERT(mInputs.Length() == 1);
+      MOZ_RELEASE_ASSERT(mInputs.Length() == 1);
       AudioSegment data;
       DeviceInputConsumerTrack::GetInputSourceData(data, aFrom, aTo);
       GetData<AudioSegment>()->AppendFrom(&data);
@@ -555,7 +603,7 @@ class TestDeviceInputConsumerTrack : public DeviceInputConsumerTrack {
       return 0;
     }
     DeviceInputTrack* t = mInputs[0]->GetSource()->AsDeviceInputTrack();
-    MOZ_ASSERT(t);
+    MOZ_RELEASE_ASSERT(t);
     return t->NumberOfChannels();
   }
 
@@ -574,30 +622,23 @@ TEST(TestAudioTrackGraph, DeviceChangedCallback)
       CubebUtils::PreferredSampleRate(/* aShouldResistFingerprinting */ false),
       nullptr, GetMainThreadSerialEventTarget());
 
-  class TestAudioDataListener : public AudioDataListener {
+  class TestAudioDataListener : public StrictMock<MockAudioDataListener> {
    public:
-    TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice)
-        : mChannelCount(aChannelCount),
-          mIsVoice(aIsVoice),
-          mDeviceChangedCount(0) {}
-
-    uint32_t RequestedInputChannelCount(MediaTrackGraph* aGraph) override {
-      return mChannelCount;
-    }
-    bool IsVoiceInput(MediaTrackGraph* aGraph) const override {
-      return mIsVoice;
-    };
-    void DeviceChanged(MediaTrackGraph* aGraph) override {
-      ++mDeviceChangedCount;
+    TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice) {
+      EXPECT_CALL(*this, RequestedInputChannelCount)
+          .WillRepeatedly(Return(aChannelCount));
+      EXPECT_CALL(*this, RequestedInputProcessingParams)
+          .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_NONE));
+      EXPECT_CALL(*this, IsVoiceInput).WillRepeatedly(Return(aIsVoice));
+      {
+        InSequence s;
+        EXPECT_CALL(*this, DeviceChanged);
+        EXPECT_CALL(*this, Disconnect);
+      }
     }
-    void Disconnect(MediaTrackGraph* aGraph) override{/* Ignored */};
-    uint32_t DeviceChangedCount() { return mDeviceChangedCount; }
 
    private:
     ~TestAudioDataListener() = default;
-    const uint32_t mChannelCount;
-    const bool mIsVoice;
-    std::atomic<uint32_t> mDeviceChangedCount;
   };
 
   // Create a full-duplex AudioCallbackDriver by creating a NativeInputTrack.
@@ -610,7 +651,7 @@ TEST(TestAudioTrackGraph, DeviceChangedCallback)
   EXPECT_TRUE(track1->ConnectedToNativeDevice());
   EXPECT_FALSE(track1->ConnectedToNonNativeDevice());
   auto started =
-      Invoke([&] { return graphImpl->NotifyWhenDeviceStarted(nullptr); });
+      InvokeAsync([&] { return graphImpl->NotifyWhenDeviceStarted(nullptr); });
   RefPtr<SmartMockCubebStream> stream1 = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream1->mHasInput);
   EXPECT_TRUE(stream1->mHasOutput);
@@ -648,9 +689,6 @@ TEST(TestAudioTrackGraph, DeviceChangedCallback)
       WaitFor(cubeb->StreamDestroyEvent());
   EXPECT_EQ(destroyedStream.get(), stream2.get());
 
-  // Make sure we only have one device-changed event for the NativeInputTrack.
-  EXPECT_EQ(listener2->DeviceChangedCount(), 1U);
-
   // Destroy the NativeInputTrack.
   DispatchFunction([&] {
     track1->DisconnectDeviceInput();
@@ -658,9 +696,6 @@ TEST(TestAudioTrackGraph, DeviceChangedCallback)
   });
   destroyedStream = WaitFor(cubeb->StreamDestroyEvent());
   EXPECT_EQ(destroyedStream.get(), stream1.get());
-
-  // Make sure we only have one device-changed event for the NativeInputTrack.
-  EXPECT_EQ(listener1->DeviceChangedCount(), 1U);
 }
 
 // The native audio stream (a.k.a. GraphDriver) and the non-native audio stream
@@ -692,57 +727,32 @@ TEST(TestAudioTrackGraph, RestartAudioIfMaxChannelCountChanged)
 
   // A test-only AudioDataListener that simulates AudioInputProcessing's setter
   // and getter for the input channel count.
-  class TestAudioDataListener : public AudioDataListener {
+  class TestAudioDataListener : public StrictMock<MockAudioDataListener> {
    public:
-    TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice)
-        : mChannelCount(aChannelCount), mIsVoice(aIsVoice) {}
+    TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice) {
+      EXPECT_CALL(*this, RequestedInputChannelCount)
+          .WillRepeatedly(Return(aChannelCount));
+      EXPECT_CALL(*this, RequestedInputProcessingParams)
+          .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_NONE));
+      EXPECT_CALL(*this, IsVoiceInput).WillRepeatedly(Return(aIsVoice));
+      EXPECT_CALL(*this, Disconnect);
+    }
     // Main thread API
     void SetInputChannelCount(MediaTrackGraph* aGraph,
                               CubebUtils::AudioDeviceID aDevice,
                               uint32_t aChannelCount) {
-      MOZ_ASSERT(NS_IsMainThread());
-
-      struct Message : public ControlMessage {
-        MediaTrackGraph* mGraph;
-        TestAudioDataListener* mListener;
-        CubebUtils::AudioDeviceID mDevice;
-        uint32_t mChannelCount;
-
-        Message(MediaTrackGraph* aGraph, TestAudioDataListener* aListener,
-                CubebUtils::AudioDeviceID aDevice, uint32_t aChannelCount)
-            : ControlMessage(nullptr),
-              mGraph(aGraph),
-              mListener(aListener),
-              mDevice(aDevice),
-              mChannelCount(aChannelCount) {}
-        void Run() override {
-          mListener->mChannelCount = mChannelCount;
-          mGraph->ReevaluateInputDevice(mDevice);
-        }
-      };
-
-      static_cast<MediaTrackGraphImpl*>(aGraph)->AppendMessage(
-          MakeUnique<Message>(aGraph, this, aDevice, aChannelCount));
+      MOZ_RELEASE_ASSERT(NS_IsMainThread());
+      static_cast<MediaTrackGraphImpl*>(aGraph)
+          ->QueueControlMessageWithNoShutdown(
+              [this, self = RefPtr(this), aGraph, aDevice, aChannelCount] {
+                EXPECT_CALL(*this, RequestedInputChannelCount)
+                    .WillRepeatedly(Return(aChannelCount));
+                aGraph->ReevaluateInputDevice(aDevice);
+              });
     }
-    // Graph thread APIs: AudioDataListenerInterface implementations.
-    uint32_t RequestedInputChannelCount(MediaTrackGraph* aGraph) override {
-      aGraph->AssertOnGraphThread();
-      return mChannelCount;
-    }
-    bool IsVoiceInput(MediaTrackGraph* aGraph) const override {
-      return mIsVoice;
-    };
-    void DeviceChanged(MediaTrackGraph* aGraph) override { /* Ignored */
-    }
-    void Disconnect(MediaTrackGraph* aGraph) override{/* Ignored */};
 
    private:
     ~TestAudioDataListener() = default;
-
-    // Graph thread-only.
-    uint32_t mChannelCount;
-    // Any thread.
-    const bool mIsVoice;
   };
 
   // Request a new input channel count and expect to have a new stream.
@@ -841,8 +851,8 @@ TEST(TestAudioTrackGraph, RestartAudioIfMaxChannelCountChanged)
 
     EXPECT_TRUE(track1->ConnectedToNativeDevice());
     EXPECT_FALSE(track1->ConnectedToNonNativeDevice());
-    auto started =
-        Invoke([&] { return graphImpl->NotifyWhenDeviceStarted(nullptr); });
+    auto started = InvokeAsync(
+        [&] { return graphImpl->NotifyWhenDeviceStarted(nullptr); });
     nativeStream = WaitFor(cubeb->StreamInitEvent());
     EXPECT_TRUE(nativeStream->mHasInput);
     EXPECT_TRUE(nativeStream->mHasOutput);
@@ -947,30 +957,18 @@ TEST(TestAudioTrackGraph, RestartAudioIfMaxChannelCountChanged)
 // AudioDataListener. However, it only tests when MOZ_WEBRTC is defined.
 TEST(TestAudioTrackGraph, SwitchNativeInputDevice)
 {
-  class TestAudioDataListener : public AudioDataListener {
+  class TestAudioDataListener : public StrictMock<MockAudioDataListener> {
    public:
-    TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice)
-        : mChannelCount(aChannelCount),
-          mIsVoice(aIsVoice),
-          mDeviceChangedCount(0) {}
-
-    uint32_t RequestedInputChannelCount(MediaTrackGraph* aGraph) override {
-      return mChannelCount;
-    }
-    bool IsVoiceInput(MediaTrackGraph* aGraph) const override {
-      return mIsVoice;
-    };
-    void DeviceChanged(MediaTrackGraph* aGraph) override {
-      ++mDeviceChangedCount;
+    TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice) {
+      EXPECT_CALL(*this, RequestedInputChannelCount)
+          .WillRepeatedly(Return(aChannelCount));
+      EXPECT_CALL(*this, RequestedInputProcessingParams)
+          .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_NONE));
+      EXPECT_CALL(*this, IsVoiceInput).WillRepeatedly(Return(aIsVoice));
     }
-    void Disconnect(MediaTrackGraph* aGraph) override{/* Ignored */};
-    uint32_t DeviceChangedCount() { return mDeviceChangedCount; }
 
    private:
     ~TestAudioDataListener() = default;
-    const uint32_t mChannelCount;
-    const bool mIsVoice;
-    std::atomic<uint32_t> mDeviceChangedCount;
   };
 
   MockCubeb* cubeb = new MockCubeb();
@@ -1049,11 +1047,12 @@ TEST(TestAudioTrackGraph, SwitchNativeInputDevice)
   RefPtr<TestDeviceInputConsumerTrack> track1 =
       TestDeviceInputConsumerTrack::Create(graph);
   RefPtr<TestAudioDataListener> listener1 = new TestAudioDataListener(1, false);
+  EXPECT_CALL(*listener1, Disconnect);
   track1->ConnectDeviceInput(device1, listener1, PRINCIPAL_HANDLE_NONE);
   EXPECT_EQ(track1->DeviceId().value(), device1);
 
   auto started =
-      Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
+      InvokeAsync([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
 
   RefPtr<SmartMockCubebStream> stream1 = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream1->mHasInput);
@@ -1069,6 +1068,7 @@ TEST(TestAudioTrackGraph, SwitchNativeInputDevice)
   RefPtr<TestDeviceInputConsumerTrack> track2 =
       TestDeviceInputConsumerTrack::Create(graph);
   RefPtr<TestAudioDataListener> listener2 = new TestAudioDataListener(2, false);
+  EXPECT_CALL(*listener2, Disconnect).Times(2);
   track2->ConnectDeviceInput(device2, listener2, PRINCIPAL_HANDLE_NONE);
   EXPECT_EQ(track2->DeviceId().value(), device2);
 
@@ -1085,6 +1085,7 @@ TEST(TestAudioTrackGraph, SwitchNativeInputDevice)
   RefPtr<TestDeviceInputConsumerTrack> track3 =
       TestDeviceInputConsumerTrack::Create(graph);
   RefPtr<TestAudioDataListener> listener3 = new TestAudioDataListener(1, false);
+  EXPECT_CALL(*listener3, Disconnect).Times(2);
   track3->ConnectDeviceInput(device3, listener3, PRINCIPAL_HANDLE_NONE);
   EXPECT_EQ(track3->DeviceId().value(), device3);
 
@@ -1160,7 +1161,7 @@ TEST(TestAudioTrackGraph, ErrorCallback)
   // output from the graph.
   RefPtr<AudioProcessingTrack> processingTrack;
   RefPtr<AudioInputProcessing> listener;
-  auto started = Invoke([&] {
+  auto started = InvokeAsync([&] {
     processingTrack = AudioProcessingTrack::Create(graph);
     listener = new AudioInputProcessing(2);
     QueueExpectIsPassThrough(processingTrack, listener);
@@ -1225,7 +1226,7 @@ TEST(TestAudioTrackGraph, AudioProcessingTrack)
   RefPtr<ProcessedMediaTrack> outputTrack;
   RefPtr<MediaInputPort> port;
   RefPtr<AudioInputProcessing> listener;
-  auto p = Invoke([&] {
+  auto p = InvokeAsync([&] {
     processingTrack = AudioProcessingTrack::Create(graph);
     outputTrack = graph->CreateForwardedInputTrack(MediaSegment::AUDIO);
     outputTrack->QueueSetAutoend(false);
@@ -1282,7 +1283,7 @@ TEST(TestAudioTrackGraph, AudioProcessingTrack)
 
   EXPECT_EQ(estimatedFreq, inputFrequency);
   std::cerr << "PreSilence: " << preSilenceSamples << std::endl;
-  // We buffer 128 frames. See DeviceInputTrack::ProcessInput.
+  // We buffer 128 frames. See NativeInputTrack::NotifyInputData.
   EXPECT_GE(preSilenceSamples, 128U);
   // If the fallback system clock driver is doing a graph iteration before the
   // first audio driver iteration comes in, that iteration is ignored and
@@ -1297,13 +1298,17 @@ TEST(TestAudioTrackGraph, AudioProcessingTrack)
 
 TEST(TestAudioTrackGraph, ReConnectDeviceInput)
 {
-  MockCubeb* cubeb = new MockCubeb();
+  MockCubeb* cubeb = new MockCubeb(MockCubeb::RunningMode::Manual);
   CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
 
   // 48k is a native processing rate, and avoids a resampling pass compared
   // to 44.1k. The resampler may add take a few frames to stabilize, which show
   // as unexected discontinuities in the test.
   const TrackRate rate = 48000;
+  // Use a drift factor so that we don't dont produce perfect 10ms-chunks.
+  // This will exercise whatever buffers are in the audio processing pipeline,
+  // and the bookkeeping surrounding them.
+  const long step = 10 * rate * 1111 / 1000 / PR_MSEC_PER_SEC;
 
   MediaTrackGraph* graph = MediaTrackGraphImpl::GetInstance(
       MediaTrackGraph::SYSTEM_THREAD_DRIVER, /*Window ID*/ 1, rate, nullptr,
@@ -1315,7 +1320,8 @@ TEST(TestAudioTrackGraph, ReConnectDeviceInput)
   RefPtr<ProcessedMediaTrack> outputTrack;
   RefPtr<MediaInputPort> port;
   RefPtr<AudioInputProcessing> listener;
-  auto p = Invoke([&] {
+  RefPtr<OnFallbackListener> fallbackListener;
+  DispatchFunction([&] {
     processingTrack = AudioProcessingTrack::Create(graph);
     outputTrack = graph->CreateForwardedInputTrack(MediaSegment::AUDIO);
     outputTrack->QueueSetAutoend(false);
@@ -1337,54 +1343,65 @@ TEST(TestAudioTrackGraph, ReConnectDeviceInput)
     settings.mAgc2Forced = true;
     QueueApplySettings(processingTrack, listener, settings);
 
-    return graph->NotifyWhenDeviceStarted(nullptr);
+    fallbackListener = new OnFallbackListener(processingTrack);
+    processingTrack->AddListener(fallbackListener);
   });
 
   RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream->mHasInput);
-  Unused << WaitFor(p);
 
-  // Set a drift factor so that we don't dont produce perfect 10ms-chunks. This
-  // will exercise whatever buffers are in the audio processing pipeline, and
-  // the bookkeeping surrounding them.
-  stream->SetDriftFactor(1.111);
+  while (
+      stream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
 
-  // Wait for a second worth of audio data. GoFaster is dispatched through a
-  // ControlMessage so that it is called in the first audio driver iteration.
-  // Otherwise the audio driver might be going very fast while the fallback
-  // system clock driver is still in an iteration.
-  DispatchFunction([&] {
-    processingTrack->GraphImpl()->AppendMessage(MakeUnique<GoFaster>(cubeb));
-  });
-  {
-    uint32_t totalFrames = 0;
-    WaitUntil(stream->FramesProcessedEvent(), [&](uint32_t aFrames) {
-      totalFrames += aFrames;
-      return totalFrames > static_cast<uint32_t>(graph->GraphRate());
-    });
+  // Wait for the AudioCallbackDriver to come into effect.
+  while (fallbackListener->OnFallback()) {
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::Yes);
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Iterate for a second worth of audio data.
+  for (long frames = 0; frames < graph->GraphRate(); frames += step) {
+    stream->ManualDataCallback(step);
   }
-  cubeb->DontGoFaster();
 
   // Close the input to see that no asserts go off due to bad state.
   DispatchFunction([&] { processingTrack->DisconnectDeviceInput(); });
 
-  stream = WaitFor(cubeb->StreamInitEvent());
+  // Dispatch the disconnect message.
+  ProcessEventQueue();
+  // Run the disconnect message.
+  EXPECT_EQ(stream->ManualDataCallback(0),
+            MockCubebStream::KeepProcessing::Yes);
+  // Switch driver.
+  auto initPromise = TakeN(cubeb->StreamInitEvent(), 1);
+  EXPECT_EQ(stream->ManualDataCallback(0), MockCubebStream::KeepProcessing::No);
+  std::tie(stream) = WaitFor(initPromise).unwrap()[0];
   EXPECT_FALSE(stream->mHasInput);
-  Unused << WaitFor(
-      Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); }));
 
-  // Output-only. Wait for another second before unmuting.
-  DispatchFunction([&] {
-    processingTrack->GraphImpl()->AppendMessage(MakeUnique<GoFaster>(cubeb));
-  });
-  {
-    uint32_t totalFrames = 0;
-    WaitUntil(stream->FramesProcessedEvent(), [&](uint32_t aFrames) {
-      totalFrames += aFrames;
-      return totalFrames > static_cast<uint32_t>(graph->GraphRate());
-    });
+  while (
+      stream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Wait for the new AudioCallbackDriver to come into effect.
+  fallbackListener->Reset();
+  while (fallbackListener->OnFallback()) {
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::Yes);
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Output-only. Iterate for another second before unmuting.
+  for (long frames = 0; frames < graph->GraphRate(); frames += step) {
+    stream->ManualDataCallback(step);
   }
-  cubeb->DontGoFaster();
 
   // Re-open the input to again see that no asserts go off due to bad state.
   DispatchFunction([&] {
@@ -1392,27 +1409,40 @@ TEST(TestAudioTrackGraph, ReConnectDeviceInput)
     processingTrack->ConnectDeviceInput(deviceId, listener,
                                         PRINCIPAL_HANDLE_NONE);
   });
-
-  stream = WaitFor(cubeb->StreamInitEvent());
+  // Dispatch the connect message.
+  ProcessEventQueue();
+  // Run the connect message.
+  EXPECT_EQ(stream->ManualDataCallback(0),
+            MockCubebStream::KeepProcessing::Yes);
+  // Switch driver.
+  initPromise = TakeN(cubeb->StreamInitEvent(), 1);
+  EXPECT_EQ(stream->ManualDataCallback(0), MockCubebStream::KeepProcessing::No);
+  std::tie(stream) = WaitFor(initPromise).unwrap()[0];
   EXPECT_TRUE(stream->mHasInput);
-  Unused << WaitFor(
-      Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); }));
 
-  // Full-duplex. Wait for another second before finishing.
-  DispatchFunction([&] {
-    processingTrack->GraphImpl()->AppendMessage(MakeUnique<GoFaster>(cubeb));
-  });
-  {
-    uint32_t totalFrames = 0;
-    WaitUntil(stream->FramesProcessedEvent(), [&](uint32_t aFrames) {
-      totalFrames += aFrames;
-      return totalFrames > static_cast<uint32_t>(graph->GraphRate());
-    });
+  while (
+      stream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Wait for the new AudioCallbackDriver to come into effect.
+  fallbackListener->Reset();
+  while (fallbackListener->OnFallback()) {
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::Yes);
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Full-duplex. Iterate for another second before finishing.
+  for (long frames = 0; frames < graph->GraphRate(); frames += step) {
+    stream->ManualDataCallback(step);
   }
-  cubeb->DontGoFaster();
 
   // Clean up.
   DispatchFunction([&] {
+    processingTrack->RemoveListener(fallbackListener);
     outputTrack->RemoveAudioOutput((void*)1);
     outputTrack->Destroy();
     port->Destroy();
@@ -1422,7 +1452,14 @@ TEST(TestAudioTrackGraph, ReConnectDeviceInput)
     processingTrack->Destroy();
   });
 
-  uint32_t inputRate = stream->SampleRate();
+  // Dispatch the clean-up messages.
+  ProcessEventQueue();
+  // Run the clean-up messages.
+  EXPECT_EQ(stream->ManualDataCallback(0),
+            MockCubebStream::KeepProcessing::Yes);
+  // Shut down driver.
+  EXPECT_EQ(stream->ManualDataCallback(0), MockCubebStream::KeepProcessing::No);
+
   uint32_t inputFrequency = stream->InputFrequency();
   uint64_t preSilenceSamples;
   uint32_t estimatedFreq;
@@ -1431,17 +1468,12 @@ TEST(TestAudioTrackGraph, ReConnectDeviceInput)
       WaitFor(stream->OutputVerificationEvent());
 
   EXPECT_EQ(estimatedFreq, inputFrequency);
-  std::cerr << "PreSilence: " << preSilenceSamples << std::endl;
-  // We buffer 10ms worth of frames in non-passthrough mode, plus up to 128
-  // frames as we round up to the nearest block. See
-  // AudioInputProcessing::Process and DeviceInputTrack::PrcoessInput.
-  EXPECT_GE(preSilenceSamples, 128U + inputRate / 100);
-  // If the fallback system clock driver is doing a graph iteration before the
-  // first audio driver iteration comes in, that iteration is ignored and
-  // results in zeros. It takes one fallback driver iteration *after* the audio
-  // driver has started to complete the switch, *usually* resulting two
-  // 10ms-iterations of silence; sometimes only one.
-  EXPECT_LE(preSilenceSamples, 128U + 3 * inputRate / 100 /* 3*10ms */);
+  std::cerr << "PreSilence: " << preSilenceSamples << "\n";
+  // We buffer 128 frames. See NativeInputTrack::NotifyInputData.
+  // When not in passthrough the AudioInputProcessing packetizer also buffers
+  // 10ms of silence, pulled in from NativeInputTrack when being run by the
+  // fallback SystemClockDriver.
+  EXPECT_EQ(preSilenceSamples, WEBAUDIO_BLOCK_SIZE + rate / 100);
   // The waveform from AudioGenerator starts at 0, but we don't control its
   // ending, so we expect a discontinuity there. Note that this check is only
   // for the waveform on the stream *after* re-opening the input.
@@ -1467,7 +1499,7 @@ float rmsf32(AudioDataValue* aSamples, uint32_t aChannels, uint32_t aFrames) {
 
 TEST(TestAudioTrackGraph, AudioProcessingTrackDisabling)
 {
-  MockCubeb* cubeb = new MockCubeb();
+  MockCubeb* cubeb = new MockCubeb(MockCubeb::RunningMode::Manual);
   CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
 
   MediaTrackGraph* graph = MediaTrackGraphImpl::GetInstance(
@@ -1481,7 +1513,8 @@ TEST(TestAudioTrackGraph, AudioProcessingTrackDisabling)
   RefPtr<ProcessedMediaTrack> outputTrack;
   RefPtr<MediaInputPort> port;
   RefPtr<AudioInputProcessing> listener;
-  auto p = Invoke([&] {
+  RefPtr<OnFallbackListener> fallbackListener;
+  DispatchFunction([&] {
     processingTrack = AudioProcessingTrack::Create(graph);
     outputTrack = graph->CreateForwardedInputTrack(MediaSegment::AUDIO);
     outputTrack->QueueSetAutoend(false);
@@ -1495,32 +1528,36 @@ TEST(TestAudioTrackGraph, AudioProcessingTrackDisabling)
                                         PRINCIPAL_HANDLE_NONE);
     processingTrack->GraphImpl()->AppendMessage(
         MakeUnique<StartInputProcessing>(processingTrack, listener));
-    return graph->NotifyWhenDeviceStarted(nullptr);
+    fallbackListener = new OnFallbackListener(processingTrack);
+    processingTrack->AddListener(fallbackListener);
   });
 
+  ProcessEventQueue();
+
   RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream->mHasInput);
-  Unused << WaitFor(p);
+
+  while (
+      stream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Wait for the AudioCallbackDriver to come into effect.
+  while (fallbackListener->OnFallback()) {
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::Yes);
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
 
   stream->SetOutputRecordingEnabled(true);
 
   // Wait for a second worth of audio data.
-  uint64_t targetPosition = graph->GraphRate();
-  auto AdvanceToTargetPosition = [&] {
-    DispatchFunction([&] {
-      processingTrack->GraphImpl()->AppendMessage(MakeUnique<GoFaster>(cubeb));
-    });
-    WaitUntil(stream->FramesProcessedEvent(), [&](uint32_t aFrames) {
-      // Position() gives a more up-to-date indication than summing aFrames if
-      // multiple events are queued.
-      if (stream->Position() < targetPosition) {
-        return false;
-      }
-      cubeb->DontGoFaster();
-      return true;
-    });
-  };
-  AdvanceToTargetPosition();
+  const long step = graph->GraphRate() / 100;  // 10ms
+  for (long frames = 0; frames < graph->GraphRate(); frames += step) {
+    stream->ManualDataCallback(step);
+  }
 
   const uint32_t ITERATION_COUNT = 5;
   uint32_t iterations = ITERATION_COUNT;
@@ -1537,8 +1574,11 @@ TEST(TestAudioTrackGraph, AudioProcessingTrackDisabling)
       }
     });
 
-    targetPosition += graph->GraphRate();
-    AdvanceToTargetPosition();
+    ProcessEventQueue();
+
+    for (long frames = 0; frames < graph->GraphRate(); frames += step) {
+      stream->ManualDataCallback(step);
+    }
   }
 
   // Clean up.
@@ -1548,10 +1588,18 @@ TEST(TestAudioTrackGraph, AudioProcessingTrackDisabling)
     port->Destroy();
     processingTrack->GraphImpl()->AppendMessage(
         MakeUnique<StopInputProcessing>(processingTrack, listener));
+    processingTrack->RemoveListener(fallbackListener);
     processingTrack->DisconnectDeviceInput();
     processingTrack->Destroy();
   });
 
+  ProcessEventQueue();
+
+  // Close the input and switch driver.
+  while (stream->ManualDataCallback(0) != MockCubebStream::KeepProcessing::No) {
+    std::cerr << "Waiting for switch...\n";
+  }
+
   uint64_t preSilenceSamples;
   uint32_t estimatedFreq;
   uint32_t nrDiscontinuities;
@@ -1604,7 +1652,7 @@ TEST(TestAudioTrackGraph, SetRequestedInputChannelCount)
   EXPECT_EQ(track1->DeviceId().value(), device1);
 
   auto started =
-      Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
+      InvokeAsync([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
 
   RefPtr<SmartMockCubebStream> stream1 = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream1->mHasInput);
@@ -1829,7 +1877,7 @@ TEST(TestAudioTrackGraph, RestartAudioIfProcessingMaxChannelCountChanged)
     EXPECT_EQ(track1->DeviceId().value(), nativeDevice);
 
     auto started =
-        Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
+        InvokeAsync([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
 
     nativeStream = WaitFor(cubeb->StreamInitEvent());
     EXPECT_TRUE(nativeStream->mHasInput);
@@ -1961,44 +2009,23 @@ TEST(TestAudioTrackGraph, SetInputChannelCountBeforeAudioCallbackDriver)
   const CubebUtils::AudioDeviceID deviceId = (CubebUtils::AudioDeviceID)1;
   RefPtr<AudioProcessingTrack> track;
   RefPtr<AudioInputProcessing> listener;
-  {
-    MozPromiseHolder<GenericPromise> h;
-    RefPtr<GenericPromise> p = h.Ensure(__func__);
-
-    struct GuardMessage : public ControlMessage {
-      MozPromiseHolder<GenericPromise> mHolder;
-
-      GuardMessage(MediaTrack* aTrack,
-                   MozPromiseHolder<GenericPromise>&& aHolder)
-          : ControlMessage(aTrack), mHolder(std::move(aHolder)) {}
-      void Run() override {
-        mTrack->GraphImpl()->Dispatch(NS_NewRunnableFunction(
-            "TestAudioTrackGraph::SetInputChannel::Message::Resolver",
-            [holder = std::move(mHolder)]() mutable {
-              holder.Resolve(true, __func__);
-            }));
-      }
-    };
-
-    DispatchFunction([&] {
-      track = AudioProcessingTrack::Create(graph);
-      listener = new AudioInputProcessing(2);
-      QueueExpectIsPassThrough(track, listener);
-      track->SetInputProcessing(listener);
-
-      MediaEnginePrefs settings;
-      settings.mChannels = 1;
-      QueueApplySettings(track, listener, settings);
+  DispatchFunction([&] {
+    track = AudioProcessingTrack::Create(graph);
+    listener = new AudioInputProcessing(2);
+    QueueExpectIsPassThrough(track, listener);
+    track->SetInputProcessing(listener);
 
-      track->GraphImpl()->AppendMessage(
-          MakeUnique<GuardMessage>(track, std::move(h)));
-    });
+    MediaEnginePrefs settings;
+    settings.mChannels = 1;
+    QueueApplySettings(track, listener, settings);
+  });
 
-    Unused << WaitFor(p);
-  }
+  // Wait for AudioCallbackDriver to init output-only stream.
+  RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
+  EXPECT_FALSE(stream->mHasInput);
+  EXPECT_TRUE(stream->mHasOutput);
 
   // Open a full-duplex AudioCallbackDriver.
-
   RefPtr<MediaInputPort> port;
   DispatchFunction([&] {
     track->GraphImpl()->AppendMessage(
@@ -2006,22 +2033,13 @@ TEST(TestAudioTrackGraph, SetInputChannelCountBeforeAudioCallbackDriver)
     track->ConnectDeviceInput(deviceId, listener, PRINCIPAL_HANDLE_NONE);
   });
 
-  // MediaTrackGraph will create a output-only AudioCallbackDriver in
-  // CheckDriver before we open an audio input above, since AudioProcessingTrack
-  // is a audio-type MediaTrack, so we need to wait here until the duplex
-  // AudioCallbackDriver is created.
-  RefPtr<SmartMockCubebStream> stream;
-  SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
-      "TEST(TestAudioTrackGraph, SetInputChannelCountBeforeAudioCallbackDriver)"_ns,
-      [&] {
-        stream = WaitFor(cubeb->StreamInitEvent());
-        EXPECT_TRUE(stream->mHasOutput);
-        return stream->mHasInput;
-      });
+  stream = WaitFor(cubeb->StreamInitEvent());
+  EXPECT_TRUE(stream->mHasInput);
+  EXPECT_TRUE(stream->mHasOutput);
   EXPECT_EQ(stream->InputChannels(), 1U);
 
   Unused << WaitFor(
-      Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); }));
+      InvokeAsync([&] { return graph->NotifyWhenDeviceStarted(nullptr); }));
 
   // Clean up.
   DispatchFunction([&] {
@@ -2257,7 +2275,7 @@ TEST(TestAudioTrackGraph, SwitchNativeAudioProcessingTrack)
   EXPECT_EQ(track1->DeviceId().value(), device1);
 
   auto started =
-      Invoke([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
+      InvokeAsync([&] { return graph->NotifyWhenDeviceStarted(nullptr); });
 
   RefPtr<SmartMockCubebStream> stream1 = WaitFor(cubeb->StreamInitEvent());
   EXPECT_TRUE(stream1->mHasInput);
@@ -2350,23 +2368,6 @@ TEST(TestAudioTrackGraph, SwitchNativeAudioProcessingTrack)
   std::cerr << "No native input now" << std::endl;
 }
 
-class OnFallbackListener : public MediaTrackListener {
-  const RefPtr<MediaTrack> mTrack;
-  Atomic<bool> mOnFallback{true};
-
- public:
-  explicit OnFallbackListener(MediaTrack* aTrack) : mTrack(aTrack) {}
-
-  bool OnFallback() { return mOnFallback; }
-
-  void NotifyOutput(MediaTrackGraph*, TrackTime) override {
-    if (auto* ad =
-            mTrack->GraphImpl()->CurrentDriver()->AsAudioCallbackDriver()) {
-      mOnFallback = ad->OnFallback();
-    }
-  }
-};
-
 void TestCrossGraphPort(uint32_t aInputRate, uint32_t aOutputRate,
                         float aDriftFactor, uint32_t aRunTimeSeconds = 10,
                         uint32_t aNumExpectedUnderruns = 0) {
@@ -2409,6 +2410,13 @@ void TestCrossGraphPort(uint32_t aInputRate, uint32_t aOutputRate,
 
   RefPtr<SmartMockCubebStream> inputStream = WaitFor(cubeb->StreamInitEvent());
 
+  while (
+      inputStream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
   // Wait for the primary AudioCallbackDriver to come into effect.
   while (primaryFallbackListener->OnFallback()) {
     EXPECT_EQ(inputStream->ManualDataCallback(0),
@@ -2441,6 +2449,13 @@ void TestCrossGraphPort(uint32_t aInputRate, uint32_t aOutputRate,
   RefPtr<SmartMockCubebStream> partnerStream =
       WaitFor(cubeb->StreamInitEvent());
 
+  while (
+      partnerStream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
   // Process the CrossGraphTransmitter on the primary graph.
   EXPECT_EQ(inputStream->ManualDataCallback(0),
             MockCubebStream::KeepProcessing::Yes);
@@ -2453,8 +2468,7 @@ void TestCrossGraphPort(uint32_t aInputRate, uint32_t aOutputRate,
   }
 
   DispatchFunction([&] { receiver->RemoveListener(partnerFallbackListener); });
-  while (NS_ProcessNextEvent(nullptr, false)) {
-  }
+  ProcessEventQueue();
 
   nsIThread* currentThread = NS_GetCurrentThread();
   cubeb_state inputState = CUBEB_STATE_STARTED;
@@ -2499,8 +2513,7 @@ void TestCrossGraphPort(uint32_t aInputRate, uint32_t aOutputRate,
     processingTrack->Destroy();
   });
 
-  while (NS_ProcessNextEvent(nullptr, false)) {
-  }
+  ProcessEventQueue();
 
   EXPECT_EQ(inputStream->ManualDataCallback(0),
             MockCubebStream::KeepProcessing::Yes);
@@ -2816,6 +2829,221 @@ TEST(TestAudioInputProcessing, ClockDriftExpectation)
 }
 #endif  // MOZ_WEBRTC
 
+TEST(TestAudioTrackGraph, PlatformProcessing)
+{
+  constexpr cubeb_input_processing_params allParams =
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION |
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION |
+      CUBEB_INPUT_PROCESSING_PARAM_AUTOMATIC_GAIN_CONTROL |
+      CUBEB_INPUT_PROCESSING_PARAM_VOICE_ISOLATION;
+  MockCubeb* cubeb = new MockCubeb(MockCubeb::RunningMode::Manual);
+  cubeb->SetSupportedInputProcessingParams(allParams, CUBEB_OK);
+  CubebUtils::ForceSetCubebContext(cubeb->AsCubebContext());
+
+  MediaTrackGraph* graph = MediaTrackGraphImpl::GetInstance(
+      MediaTrackGraph::SYSTEM_THREAD_DRIVER, /*Window ID*/ 1,
+      CubebUtils::PreferredSampleRate(/* aShouldResistFingerprinting */ false),
+      nullptr, GetMainThreadSerialEventTarget());
+
+  const CubebUtils::AudioDeviceID device = (CubebUtils::AudioDeviceID)1;
+
+  // Set up mock listener.
+  RefPtr<MockAudioDataListener> listener = MakeRefPtr<MockAudioDataListener>();
+  EXPECT_CALL(*listener, IsVoiceInput).WillRepeatedly(Return(true));
+  EXPECT_CALL(*listener, RequestedInputChannelCount).WillRepeatedly(Return(1));
+  EXPECT_CALL(*listener, RequestedInputProcessingParams)
+      .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION));
+  EXPECT_CALL(*listener, Disconnect);
+
+  // Expectations.
+  const Result<cubeb_input_processing_params, int> notSupportedResult(
+      Err(CUBEB_ERROR_NOT_SUPPORTED));
+  const Result<cubeb_input_processing_params, int> errorResult(
+      Err(CUBEB_ERROR));
+  const Result<cubeb_input_processing_params, int> noneResult(
+      CUBEB_INPUT_PROCESSING_PARAM_NONE);
+  const Result<cubeb_input_processing_params, int> echoResult(
+      CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION);
+  const Result<cubeb_input_processing_params, int> noiseResult(
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION);
+  Atomic<int> numProcessingParamsResults(0);
+  {
+    InSequence s;
+    // On first driver start.
+    EXPECT_CALL(*listener,
+                NotifySetRequestedInputProcessingParamsResult(
+                    graph, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                    Eq(std::ref(echoResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+    // After requesting something else.
+    EXPECT_CALL(*listener,
+                NotifySetRequestedInputProcessingParamsResult(
+                    graph, CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION,
+                    Eq(std::ref(noiseResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+    // After error request.
+    EXPECT_CALL(*listener,
+                NotifySetRequestedInputProcessingParamsResult(
+                    graph, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                    Eq(std::ref(errorResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+    // After requesting None.
+    EXPECT_CALL(*listener, NotifySetRequestedInputProcessingParamsResult(
+                               graph, CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                               Eq(std::ref(noneResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+    // After driver switch.
+    EXPECT_CALL(*listener, NotifySetRequestedInputProcessingParamsResult(
+                               graph, CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                               Eq(std::ref(noneResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+    // After requesting something not supported.
+    EXPECT_CALL(*listener,
+                NotifySetRequestedInputProcessingParamsResult(
+                    graph, CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION,
+                    Eq(std::ref(noneResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+    // After requesting something with backend not supporting processing params.
+    EXPECT_CALL(*listener,
+                NotifySetRequestedInputProcessingParamsResult(
+                    graph, CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION,
+                    Eq(std::ref(notSupportedResult))))
+        .WillOnce([&] { ++numProcessingParamsResults; });
+  }
+
+  // Open a device.
+  RefPtr<TestDeviceInputConsumerTrack> track;
+  RefPtr<OnFallbackListener> fallbackListener;
+  DispatchFunction([&] {
+    track = TestDeviceInputConsumerTrack::Create(graph);
+    track->ConnectDeviceInput(device, listener, PRINCIPAL_HANDLE_NONE);
+    fallbackListener = new OnFallbackListener(track);
+    track->AddListener(fallbackListener);
+  });
+
+  RefPtr<SmartMockCubebStream> stream = WaitFor(cubeb->StreamInitEvent());
+  EXPECT_TRUE(stream->mHasInput);
+  EXPECT_TRUE(stream->mHasOutput);
+  EXPECT_EQ(stream->InputChannels(), 1U);
+  EXPECT_EQ(stream->GetInputDeviceID(), device);
+
+  while (
+      stream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  const auto waitForResult = [&](int aNumResult) {
+    while (numProcessingParamsResults < aNumResult) {
+      EXPECT_EQ(stream->ManualDataCallback(0),
+                MockCubebStream::KeepProcessing::Yes);
+      NS_ProcessNextEvent();
+      std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    }
+  };
+
+  // Wait for the AudioCallbackDriver to come into effect.
+  while (fallbackListener->OnFallback()) {
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::Yes);
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Wait for the first result after driver creation.
+  waitForResult(1);
+
+  // Request new processing params.
+  EXPECT_CALL(*listener, RequestedInputProcessingParams)
+      .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION));
+  waitForResult(2);
+
+  // Test with returning error on new request.
+  cubeb->SetInputProcessingApplyRv(CUBEB_ERROR);
+  EXPECT_CALL(*listener, RequestedInputProcessingParams)
+      .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION));
+  waitForResult(3);
+
+  // Test unsetting all params.
+  cubeb->SetInputProcessingApplyRv(CUBEB_OK);
+  EXPECT_CALL(*listener, RequestedInputProcessingParams)
+      .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_NONE));
+  waitForResult(4);
+
+  // Switch driver.
+  EXPECT_CALL(*listener, RequestedInputChannelCount).WillRepeatedly(Return(2));
+  DispatchFunction([&] {
+    track->QueueControlMessageWithNoShutdown(
+        [&] { graph->ReevaluateInputDevice(device); });
+  });
+  ProcessEventQueue();
+  // Process the reevaluation message.
+  EXPECT_EQ(stream->ManualDataCallback(0),
+            MockCubebStream::KeepProcessing::Yes);
+  // Perform the switch.
+  auto initPromise = TakeN(cubeb->StreamInitEvent(), 1);
+  EXPECT_EQ(stream->ManualDataCallback(0), MockCubebStream::KeepProcessing::No);
+  std::tie(stream) = WaitFor(initPromise).unwrap()[0];
+  EXPECT_TRUE(stream->mHasInput);
+  EXPECT_TRUE(stream->mHasOutput);
+  EXPECT_EQ(stream->InputChannels(), 2U);
+  EXPECT_EQ(stream->GetInputDeviceID(), device);
+
+  while (
+      stream->State()
+          .map([](cubeb_state aState) { return aState != CUBEB_STATE_STARTED; })
+          .valueOr(true)) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Wait for the new AudioCallbackDriver to come into effect.
+  fallbackListener->Reset();
+  while (fallbackListener->OnFallback()) {
+    EXPECT_EQ(stream->ManualDataCallback(0),
+              MockCubebStream::KeepProcessing::Yes);
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+
+  // Wait for the first result after driver creation.
+  waitForResult(5);
+
+  // Test requesting something not supported.
+  cubeb->SetSupportedInputProcessingParams(
+      CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION |
+          CUBEB_INPUT_PROCESSING_PARAM_AUTOMATIC_GAIN_CONTROL |
+          CUBEB_INPUT_PROCESSING_PARAM_VOICE_ISOLATION,
+      CUBEB_OK);
+  EXPECT_CALL(*listener, RequestedInputProcessingParams)
+      .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_ECHO_CANCELLATION));
+  waitForResult(6);
+
+  // Test requesting something when unsupported by backend.
+  cubeb->SetSupportedInputProcessingParams(CUBEB_INPUT_PROCESSING_PARAM_NONE,
+                                           CUBEB_ERROR_NOT_SUPPORTED);
+  EXPECT_CALL(*listener, RequestedInputProcessingParams)
+      .WillRepeatedly(Return(CUBEB_INPUT_PROCESSING_PARAM_NOISE_SUPPRESSION));
+  waitForResult(7);
+
+  // Clean up.
+  DispatchFunction([&] {
+    track->RemoveListener(fallbackListener);
+    track->Destroy();
+  });
+  ProcessEventQueue();
+  // Process the destroy message.
+  EXPECT_EQ(stream->ManualDataCallback(0),
+            MockCubebStream::KeepProcessing::Yes);
+  // Shut down.
+  EXPECT_EQ(stream->ManualDataCallback(0), MockCubebStream::KeepProcessing::No);
+  RefPtr<SmartMockCubebStream> destroyedStream =
+      WaitFor(cubeb->StreamDestroyEvent());
+  EXPECT_EQ(destroyedStream.get(), stream.get());
+  {
+    NativeInputTrack* native = graph->GetNativeInputTrackMainThread();
+    ASSERT_TRUE(!native);
+  }
+}
+
 #undef Invoke
 #undef DispatchFunction
 #undef DispatchMethod
diff --git a/dom/media/gtest/TestCDMStorage.cpp b/dom/media/gtest/TestCDMStorage.cpp
index d6249cc95f..57bbbd9298 100644
--- a/dom/media/gtest/TestCDMStorage.cpp
+++ b/dom/media/gtest/TestCDMStorage.cpp
@@ -58,7 +58,7 @@ template <typename T>
 static nsresult EnumerateCDMStorageDir(const nsACString& aDir, T&& aDirIter) {
   RefPtr<GeckoMediaPluginServiceParent> service =
       GeckoMediaPluginServiceParent::GetSingleton();
-  MOZ_ASSERT(service);
+  MOZ_RELEASE_ASSERT(service);
 
   // $profileDir/gmp/$platform/
   nsCOMPtr<nsIFile> path;
@@ -94,7 +94,7 @@ class GMPShutdownObserver : public nsIRunnable, public nsIObserver {
   NS_DECL_THREADSAFE_ISUPPORTS
 
   NS_IMETHOD Run() override {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     nsCOMPtr<nsIObserverService> observerService =
         mozilla::services::GetObserverService();
     EXPECT_TRUE(observerService);
@@ -133,7 +133,7 @@ class NotifyObserversTask : public Runnable {
   explicit NotifyObserversTask(const char* aTopic)
       : mozilla::Runnable("NotifyObserversTask"), mTopic(aTopic) {}
   NS_IMETHOD Run() override {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     nsCOMPtr<nsIObserverService> observerService =
         mozilla::services::GetObserverService();
     if (observerService) {
@@ -153,7 +153,7 @@ class ClearCDMStorageTask : public nsIRunnable, public nsIObserver {
   NS_DECL_THREADSAFE_ISUPPORTS
 
   NS_IMETHOD Run() override {
-    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
     nsCOMPtr<nsIObserverService> observerService =
         mozilla::services::GetObserverService();
     EXPECT_TRUE(observerService);
@@ -272,7 +272,7 @@ static nsCString GetNodeId(const nsAString& aOrigin,
 static bool IsCDMStorageIsEmpty() {
   RefPtr<GeckoMediaPluginServiceParent> service =
       GeckoMediaPluginServiceParent::GetSingleton();
-  MOZ_ASSERT(service);
+  MOZ_RELEASE_ASSERT(service);
   nsCOMPtr<nsIFile> storage;
   nsresult rv = service->GetStorageDir(getter_AddRefs(storage));
   EXPECT_NS_SUCCEEDED(rv);
@@ -286,14 +286,14 @@ static bool IsCDMStorageIsEmpty() {
 static void AssertIsOnGMPThread() {
   RefPtr<GeckoMediaPluginService> service =
       GeckoMediaPluginService::GetGeckoMediaPluginService();
-  MOZ_ASSERT(service);
+  MOZ_RELEASE_ASSERT(service);
   nsCOMPtr<nsIThread> thread;
   service->GetThread(getter_AddRefs(thread));
-  MOZ_ASSERT(thread);
+  MOZ_RELEASE_ASSERT(thread);
   nsCOMPtr<nsIThread> currentThread;
-  DebugOnly<nsresult> rv = NS_GetCurrentThread(getter_AddRefs(currentThread));
-  MOZ_ASSERT(NS_SUCCEEDED(rv));
-  MOZ_ASSERT(currentThread == thread);
+  nsresult rv = NS_GetCurrentThread(getter_AddRefs(currentThread));
+  MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+  MOZ_RELEASE_ASSERT(currentThread == thread);
 }
 
 class CDMStorageTest {
@@ -1049,8 +1049,8 @@ class CDMStorageTest {
 
     constexpr auto data = "Just_some_arbitrary_data."_ns;
 
-    MOZ_ASSERT(longRecordName.Length() < GMP_MAX_RECORD_NAME_SIZE);
-    MOZ_ASSERT(longRecordName.Length() > 260);  // Windows MAX_PATH
+    MOZ_RELEASE_ASSERT(longRecordName.Length() < GMP_MAX_RECORD_NAME_SIZE);
+    MOZ_RELEASE_ASSERT(longRecordName.Length() > 260);  // Windows MAX_PATH
 
     nsCString response("stored ");
     response.Append(longRecordName);
diff --git a/dom/media/gtest/TestDeviceInputTrack.cpp b/dom/media/gtest/TestDeviceInputTrack.cpp
index 14b5227f9d..fca06d5e4a 100644
--- a/dom/media/gtest/TestDeviceInputTrack.cpp
+++ b/dom/media/gtest/TestDeviceInputTrack.cpp
@@ -87,7 +87,7 @@ TEST_F(TestDeviceInputTrack, DeviceInputConsumerTrack) {
   class TestDeviceInputConsumerTrack : public DeviceInputConsumerTrack {
    public:
     static TestDeviceInputConsumerTrack* Create(MediaTrackGraph* aGraph) {
-      MOZ_ASSERT(NS_IsMainThread());
+      MOZ_RELEASE_ASSERT(NS_IsMainThread());
       TestDeviceInputConsumerTrack* track =
           new TestDeviceInputConsumerTrack(aGraph->GraphRate());
       aGraph->AddTrack(track);
@@ -95,7 +95,7 @@ TEST_F(TestDeviceInputTrack, DeviceInputConsumerTrack) {
     }
 
     void Destroy() {
-      MOZ_ASSERT(NS_IsMainThread());
+      MOZ_RELEASE_ASSERT(NS_IsMainThread());
       DisconnectDeviceInput();
       DeviceInputConsumerTrack::Destroy();
     }
@@ -108,7 +108,7 @@ TEST_F(TestDeviceInputTrack, DeviceInputConsumerTrack) {
         return 0;
       }
       DeviceInputTrack* t = mInputs[0]->GetSource()->AsDeviceInputTrack();
-      MOZ_ASSERT(t);
+      MOZ_RELEASE_ASSERT(t);
       return t->NumberOfChannels();
     }
 
@@ -122,16 +122,26 @@ TEST_F(TestDeviceInputTrack, DeviceInputConsumerTrack) {
     TestAudioDataListener(uint32_t aChannelCount, bool aIsVoice)
         : mChannelCount(aChannelCount), mIsVoice(aIsVoice) {}
     // Graph thread APIs: AudioDataListenerInterface implementations.
-    uint32_t RequestedInputChannelCount(MediaTrackGraph* aGraph) override {
+    uint32_t RequestedInputChannelCount(
+        MediaTrackGraph* aGraph) const override {
       aGraph->AssertOnGraphThread();
       return mChannelCount;
     }
+    cubeb_input_processing_params RequestedInputProcessingParams(
+        MediaTrackGraph*) const override {
+      return CUBEB_INPUT_PROCESSING_PARAM_NONE;
+    }
     bool IsVoiceInput(MediaTrackGraph* aGraph) const override {
       return mIsVoice;
     };
     void DeviceChanged(MediaTrackGraph* aGraph) override { /* Ignored */
     }
     void Disconnect(MediaTrackGraph* aGraph) override{/* Ignored */};
+    void NotifySetRequestedInputProcessingParamsResult(
+        MediaTrackGraph* aGraph, cubeb_input_processing_params aRequestedParams,
+        const Result<cubeb_input_processing_params, int>& aResult) override {
+      /* Ignored */
+    }
 
    private:
     ~TestAudioDataListener() = default;
diff --git a/dom/media/gtest/TestMP4Demuxer.cpp b/dom/media/gtest/TestMP4Demuxer.cpp
index 43dfdf19a4..1a1bde8035 100644
--- a/dom/media/gtest/TestMP4Demuxer.cpp
+++ b/dom/media/gtest/TestMP4Demuxer.cpp
@@ -56,7 +56,7 @@ class MP4DemuxerBinding {
   }
 
   RefPtr<GenericPromise> CheckTrackKeyFrame(MediaTrackDemuxer* aTrackDemuxer) {
-    MOZ_ASSERT(mTaskQueue->IsCurrentThreadIn());
+    MOZ_RELEASE_ASSERT(mTaskQueue->IsCurrentThreadIn());
 
     RefPtr<MediaTrackDemuxer> track = aTrackDemuxer;
     RefPtr<MP4DemuxerBinding> binding = this;
@@ -97,7 +97,7 @@ class MP4DemuxerBinding {
   }
 
   RefPtr<GenericPromise> CheckTrackSamples(MediaTrackDemuxer* aTrackDemuxer) {
-    MOZ_ASSERT(mTaskQueue->IsCurrentThreadIn());
+    MOZ_RELEASE_ASSERT(mTaskQueue->IsCurrentThreadIn());
 
     RefPtr<MediaTrackDemuxer> track = aTrackDemuxer;
     RefPtr<MP4DemuxerBinding> binding = this;
diff --git a/dom/media/gtest/TestMediaDataEncoder.cpp b/dom/media/gtest/TestMediaDataEncoder.cpp
index 39c92fb19c..fefedcce43 100644
--- a/dom/media/gtest/TestMediaDataEncoder.cpp
+++ b/dom/media/gtest/TestMediaDataEncoder.cpp
@@ -193,7 +193,7 @@ static already_AddRefed<MediaDataEncoder> CreateH264Encoder(
 }
 
 void WaitForShutdown(const RefPtr<MediaDataEncoder>& aEncoder) {
-  MOZ_ASSERT(aEncoder);
+  MOZ_RELEASE_ASSERT(aEncoder);
 
   Maybe<bool> result;
   // media::Await() supports exclusive promises only, but ShutdownPromise is
diff --git a/dom/media/gtest/TestWebMWriter.cpp b/dom/media/gtest/TestWebMWriter.cpp
index 837ee6a2c6..5384fd7c99 100644
--- a/dom/media/gtest/TestWebMWriter.cpp
+++ b/dom/media/gtest/TestWebMWriter.cpp
@@ -223,7 +223,7 @@ struct WebMioData {
 };
 
 static int webm_read(void* aBuffer, size_t aLength, void* aUserData) {
-  NS_ASSERTION(aUserData, "aUserData must point to a valid WebMioData");
+  MOZ_RELEASE_ASSERT(aUserData, "aUserData must point to a valid WebMioData");
   WebMioData* ioData = static_cast<WebMioData*>(aUserData);
 
   // Check the read length.
@@ -247,7 +247,7 @@ static int webm_read(void* aBuffer, size_t aLength, void* aUserData) {
 }
 
 static int webm_seek(int64_t aOffset, int aWhence, void* aUserData) {
-  NS_ASSERTION(aUserData, "aUserData must point to a valid WebMioData");
+  MOZ_RELEASE_ASSERT(aUserData, "aUserData must point to a valid WebMioData");
   WebMioData* ioData = static_cast<WebMioData*>(aUserData);
 
   if (Abs(aOffset) > ioData->data.Length()) {
@@ -281,7 +281,7 @@ static int webm_seek(int64_t aOffset, int aWhence, void* aUserData) {
 }
 
 static int64_t webm_tell(void* aUserData) {
-  NS_ASSERTION(aUserData, "aUserData must point to a valid WebMioData");
+  MOZ_RELEASE_ASSERT(aUserData, "aUserData must point to a valid WebMioData");
   WebMioData* ioData = static_cast<WebMioData*>(aUserData);
   return ioData->offset.isValid() ? ioData->offset.value() : -1;
 }