Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/audio_manager.cc

Index: media/audio/audio_manager.cc
diff --git a/media/audio/audio_manager.cc b/media/audio/audio_manager.cc
index 4b98e36910f500ecd31402fcf2a7ffec1a277a74..a1d3ec9f1a38c519b417411b579989b2d7adad4f 100644
--- a/media/audio/audio_manager.cc
+++ b/media/audio/audio_manager.cc
@@ -241,38 +241,8 @@ AudioManagerHelper* GetHelper() {
 
 }  // namespace
 
-void AudioManagerDeleter::operator()(const AudioManager* instance) const {
-  CHECK(instance);
-  // We reset g_last_created here instead of in the destructor of AudioManager
-  // because the destructor runs on the audio thread. We want to always change
-  // g_last_created from the main thread.
-  if (g_last_created == instance) {
-    g_last_created = nullptr;
-  } else {
-    // We create multiple instances of AudioManager only when testing.
-    // We should not encounter this case in production.
-    LOG(WARNING) << "Multiple instances of AudioManager detected";
-  }
-
-#if defined(OS_MACOSX)
-  // If we are on Mac, tasks after this point are not executed, hence this is
-  // the only chance to delete the audio manager (which on Mac lives on the
-  // main browser thread instead of a dedicated audio thread). If we don't
-  // delete here, the CoreAudio thread can keep providing callbacks, which
-  // uses a state that is destroyed in ~BrowserMainLoop().
-  // See http://crbug.com/623703 for more details.
-  DCHECK(instance->GetTaskRunner()->BelongsToCurrentThread());
-  delete instance;
-#else
-  // AudioManager must be destroyed on the audio thread.
-  if (!instance->GetTaskRunner()->DeleteSoon(FROM_HERE, instance)) {
-    LOG(WARNING) << "Failed to delete AudioManager instance.";
-  }
-#endif
-}
-
 // Forward declaration of the platform specific AudioManager factory function.
-ScopedAudioManagerPtr CreateAudioManager(
+std::unique_ptr<AudioManager> CreateAudioManager(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
     AudioLogFactory* audio_log_factory);
@@ -300,18 +270,26 @@ AudioManager::AudioManager(
 }
 
 AudioManager::~AudioManager() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (g_last_created == this) {
+    g_last_created = nullptr;
+  } else {
+    // We create multiple instances of AudioManager only when testing.
+    // We should not encounter this case in production.
+    LOG(WARNING) << "Multiple instances of AudioManager detected";
+  }
 }
 
 // static
-ScopedAudioManagerPtr AudioManager::Create(
+std::unique_ptr<AudioManager> AudioManager::Create(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> file_task_runner,
     AudioLogFactory* audio_log_factory) {
   DCHECK(task_runner);
   DCHECK(worker_task_runner);
-  ScopedAudioManagerPtr manager = CreateAudioManager(
+  std::unique_ptr<AudioManager> manager = CreateAudioManager(
       std::move(task_runner), std::move(worker_task_runner), audio_log_factory);
 #if BUILDFLAG(ENABLE_WEBRTC)
   manager->InitializeOutputDebugRecording(std::move(file_task_runner));
@@ -320,7 +298,7 @@ ScopedAudioManagerPtr AudioManager::Create(
 }
 
 // static
-ScopedAudioManagerPtr AudioManager::CreateForTesting(
+std::unique_ptr<AudioManager> AudioManager::CreateForTesting(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
 #if defined(OS_WIN)
   GetHelper()->InitializeCOMForTesting();