Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/audio_system_impl_unittest.cc

Index: media/audio/audio_system_impl_unittest.cc
diff --git a/media/audio/audio_system_impl_unittest.cc b/media/audio/audio_system_impl_unittest.cc
index 7aa5fbf2efcc5395a65e1bdb02158ad596d28092..7f0037935c21fe8e9b0e588f1604dd106a3c8724 100644
--- a/media/audio/audio_system_impl_unittest.cc
+++ b/media/audio/audio_system_impl_unittest.cc
@@ -12,7 +12,9 @@
 #include "base/threading/thread_checker.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "media/audio/audio_device_description.h"
+#include "media/audio/audio_thread_impl.h"
 #include "media/audio/mock_audio_manager.h"
+#include "media/audio/test_audio_thread.h"
 #include "media/base/test_helpers.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -33,7 +35,6 @@ class AudioSystemImplTest : public testing::TestWithParam<bool> {
  public:
   AudioSystemImplTest()
       : use_audio_thread_(GetParam()),
-        audio_thread_("AudioSystemThread"),
         input_params_(AudioParameters::AUDIO_PCM_LINEAR,
                       CHANNEL_LAYOUT_MONO,
                       AudioParameters::kTelephoneSampleRate,
@@ -49,15 +50,8 @@ class AudioSystemImplTest : public testing::TestWithParam<bool> {
                                AudioParameters::kTelephoneSampleRate,
                                16,
                                AudioParameters::kTelephoneSampleRate / 30) {
-    if (use_audio_thread_) {
-      audio_thread_.StartAndWaitForTesting();
-      audio_manager_.reset(
-          new media::MockAudioManager(audio_thread_.task_runner()));
-    } else {
-      audio_manager_.reset(new media::MockAudioManager(
-          base::ThreadTaskRunnerHandle::Get().get()));
-    }
-
+    audio_manager_ = base::MakeUnique<MockAudioManager>(
+        base::MakeUnique<TestAudioThread>(use_audio_thread_));
     audio_manager_->SetInputStreamParameters(input_params_);
     audio_manager_->SetOutputStreamParameters(output_params_);
     audio_manager_->SetDefaultOutputStreamParameters(default_output_params_);
@@ -78,13 +72,7 @@ class AudioSystemImplTest : public testing::TestWithParam<bool> {
     EXPECT_EQ(AudioSystem::Get(), audio_system_.get());
   }
 
-  ~AudioSystemImplTest() override {
-    // Deleting |audio_manager_| on its thread.
-    audio_system_.reset();
-    EXPECT_EQ(AudioSystem::Get(), nullptr);
-    audio_manager_.reset();
-    audio_thread_.Stop();
-  }
+  ~AudioSystemImplTest() override { audio_manager_->Shutdown(); }
 
   void OnAudioParams(const AudioParameters& expected,
                      const AudioParameters& received) {
@@ -133,7 +121,7 @@ class AudioSystemImplTest : public testing::TestWithParam<bool> {
       return;
     }
     WaitableMessageLoopEvent event;
-    audio_thread_.task_runner()->PostTaskAndReply(
+    audio_manager_->GetTaskRunner()->PostTaskAndReply(
         FROM_HERE, base::Bind(&base::DoNothing), event.GetClosure());
     // Runs the loop and waits for the |audio_thread_| to call event's closure,
     // which means AudioSystem reply containing device parameters is already
@@ -154,8 +142,7 @@ class AudioSystemImplTest : public testing::TestWithParam<bool> {
   base::MessageLoop message_loop_;
   base::ThreadChecker thread_checker_;
   bool use_audio_thread_;
-  base::Thread audio_thread_;
-  MockAudioManager::UniquePtr audio_manager_;
+  std::unique_ptr<media::MockAudioManager> audio_manager_;
   std::unique_ptr<media::AudioSystem> audio_system_;
   AudioParameters input_params_;
   AudioParameters output_params_;