diff --git a/services/audio/output_controller_unittest.cc b/services/audio/output_controller_unittest.cc
index e4614e27354e1e..1f51b7d2a6c8d0 100644
--- a/services/audio/output_controller_unittest.cc
+++ b/services/audio/output_controller_unittest.cc
@@ -269,13 +269,13 @@ class MockSnooper : public Snoopable::Snooper {
 
 // A FakeAudioManager that produces MockAudioOutputStreams, and tracks the last
 // stream that was created and the last stream that was closed.
-class AudioManagerForControllerTest : public media::FakeAudioManager {
+class AudioManagerForControllerTest final : public media::FakeAudioManager {
  public:
   AudioManagerForControllerTest()
       : media::FakeAudioManager(std::make_unique<media::TestAudioThread>(false),
                                 &fake_audio_log_factory_) {}
 
-  ~AudioManagerForControllerTest() final = default;
+  ~AudioManagerForControllerTest() override = default;
 
   MockAudioOutputStream* last_created_stream() const {
     return last_created_stream_;
diff --git a/services/audio/public/cpp/output_device_unittest.cc b/services/audio/public/cpp/output_device_unittest.cc
index 7939ff04ffd41d..cdb142355b31ae 100644
--- a/services/audio/public/cpp/output_device_unittest.cc
+++ b/services/audio/public/cpp/output_device_unittest.cc
@@ -95,10 +95,10 @@ class MockAudioOutputIPC : public media::AudioOutputIPC {
   MOCK_METHOD1(SetVolume, void(double volume));
 };
 
-class FakeOutputStreamFactory : public audio::FakeStreamFactory {
+class FakeOutputStreamFactory final : public audio::FakeStreamFactory {
  public:
   FakeOutputStreamFactory() : stream_(), stream_receiver_(&stream_) {}
-  ~FakeOutputStreamFactory() final {}
+  ~FakeOutputStreamFactory() override {}
 
   void CreateOutputStream(
       mojo::PendingReceiver<media::mojom::AudioOutputStream> stream_receiver,
diff --git a/services/tracing/public/cpp/stack_sampling/loader_lock_sampling_thread_win.h b/services/tracing/public/cpp/stack_sampling/loader_lock_sampling_thread_win.h
index 2ef881727e57d7..fc0ed3b0277951 100644
--- a/services/tracing/public/cpp/stack_sampling/loader_lock_sampling_thread_win.h
+++ b/services/tracing/public/cpp/stack_sampling/loader_lock_sampling_thread_win.h
@@ -18,11 +18,11 @@ class LoaderLockSampler;
 // being held. This is a dedicated thread, instead of using the ThreadPool, so
 // that there's never a chance of the lock being sampled from a thread that
 // runs other code that takes the lock.
-class COMPONENT_EXPORT(TRACING_CPP) LoaderLockSamplingThread
+class COMPONENT_EXPORT(TRACING_CPP) LoaderLockSamplingThread final
     : public base::Thread {
  public:
   LoaderLockSamplingThread();
-  ~LoaderLockSamplingThread() final;
+  ~LoaderLockSamplingThread() override;
 
   LoaderLockSamplingThread(const LoaderLockSamplingThread& other) = delete;
   LoaderLockSamplingThread& operator=(const LoaderLockSamplingThread& other) =