Add AudioStreamRegistry. Move stream counting logic

content/browser/renderer_host/media/audio_output_delegate_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/media/audio_output_delegate.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "content/browser/audio_manager_thread.h"
 #include "content/browser/media/capture/audio_mirroring_manager.h"
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/media_observer.h"
 #include "content/public/test/test_browser_thread_bundle.h"
+#include "content/test/mock_audio_stream_registry.h"
 #include "media/audio/fake_audio_log_factory.h"
 #include "media/audio/fake_audio_manager.h"
 #include "media/base/media_switches.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using ::testing::_;
 using ::testing::InSequence;
 using ::testing::NotNull;
 using ::testing::StrictMock;
@@ skipping 37 matching lines @@
                                  int page_request_id,
                                  MediaStreamType stream_type,
                                  bool is_secure) override {}
 
   MOCK_METHOD2(OnCreatingAudioStream,
                void(int render_process_id, int render_frame_id));
 };
 
 class MockEventHandler : public AudioOutputDelegate::EventHandler {
  public:
-  MOCK_METHOD1(OnStreamStateChanged, void(bool playing));
   MOCK_METHOD3(OnStreamCreated,
                void(int stream_id,
                     base::SharedMemory* shared_memory,
                     base::CancelableSyncSocket* socket));
   MOCK_METHOD1(OnStreamError, void(int stream_id));
 };
 
 class DummyAudioOutputStream : public media::AudioOutputStream {
  public:
   // AudioOutputSteam implementation:
   bool Open() override { return true; }
   void Start(AudioSourceCallback* cb) override {}
   void Stop() override {}
   void SetVolume(double volume) override {}
   void GetVolume(double* volume) override { *volume = 1; }
   void Close() override {}
 };
 
 }  // namespace
 
 class AudioOutputDelegateTest : public testing::Test {
  public:
-  AudioOutputDelegateTest() {
+  AudioOutputDelegateTest()
+      : stream_registry_(new MockAudioStreamRegistry(kRenderProcessId)) {
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
         switches::kUseFakeDeviceForMediaStream);
 
     // This test uses real UI, IO and audio threads.
     // AudioOutputDelegate mainly interacts with the IO and audio threads,
     // but interacts with UI for bad messages, so using these threads should
     // approximate the real conditions of AudioOutputDelegate well.
     thread_bundle_ = base::MakeUnique<TestBrowserThreadBundle>(
         TestBrowserThreadBundle::Options::REAL_IO_THREAD);
     audio_thread_ = base::MakeUnique<AudioManagerThread>();
 
     audio_manager_.reset(new media::FakeAudioManager(
         audio_thread_->task_runner(), audio_thread_->worker_task_runner(),
         &log_factory_));
     media_stream_manager_ =
         base::MakeUnique<MediaStreamManager>(audio_manager_.get());
   }
 
+  ~AudioOutputDelegateTest() override {
+    stream_registry_.reset();
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE, base::Bind([]() {
+          AudioStreamRegistryImpl::
+              DetachAudioStreamsTrackerFromThreadForTesting();
+        }));
+  }
+
   // Test bodies are here, so that we can run them on the IO thread.
   void CreateTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void PlayTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     {
       InSequence s;
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(true));
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(false));
+      EXPECT_CALL(*stream_registry_, OutputStreamStateChanged(NotNull(), true));
+      EXPECT_CALL(*stream_registry_,
+                  OutputStreamStateChanged(NotNull(), false));
     }
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     delegate->OnPlayStream();
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void PauseTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     delegate->OnPauseStream();
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void PlayPausePlayTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     {
       InSequence s;
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(true));
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(false));
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(true));
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(false));
+      EXPECT_CALL(*stream_registry_, OutputStreamStateChanged(NotNull(), true));
+      EXPECT_CALL(*stream_registry_,
+                  OutputStreamStateChanged(NotNull(), false));
+      EXPECT_CALL(*stream_registry_, OutputStreamStateChanged(NotNull(), true));
+      EXPECT_CALL(*stream_registry_,
+                  OutputStreamStateChanged(NotNull(), false));
     }
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     delegate->OnPlayStream();
     delegate->OnPauseStream();
     delegate->OnPlayStream();
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void PlayPlayTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     {
       InSequence s;
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(true));
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(false));
+      EXPECT_CALL(*stream_registry_, OutputStreamStateChanged(NotNull(), true));
+      EXPECT_CALL(*stream_registry_,
+                  OutputStreamStateChanged(NotNull(), false));
     }
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     delegate->OnPlayStream();
     delegate->OnPlayStream();
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void CreateDivertTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     DummyAudioOutputStream stream;
     delegate->controller()->StartDiverting(&stream);
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void CreateDivertPauseTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     DummyAudioOutputStream stream;
     delegate->controller()->StartDiverting(&stream);
 
     SyncWithAllThreads();
     delegate->OnPauseStream();
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void PlayDivertTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     {
       InSequence s;
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(true));
-      EXPECT_CALL(event_handler_, OnStreamStateChanged(false));
+      EXPECT_CALL(*stream_registry_, OutputStreamStateChanged(NotNull(), true));
+      EXPECT_CALL(*stream_registry_,
+                  OutputStreamStateChanged(NotNull(), false));
     }
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     DummyAudioOutputStream stream;
     delegate->OnPlayStream();
     delegate->controller()->StartDiverting(&stream);
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void ErrorTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(event_handler_, OnStreamError(kStreamId));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     delegate->controller()->OnError(nullptr);
 
     SyncWithAllThreads();
 
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void CreateAndDestroyTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void PlayAndDestroyTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
 
     SyncWithAllThreads();
 
     delegate->OnPlayStream();
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
   void ErrorAndDestroyTest(base::Closure done) {
     EXPECT_CALL(media_observer_,
                 OnCreatingAudioStream(kRenderProcessId, kRenderFrameId));
     EXPECT_CALL(event_handler_,
                 OnStreamCreated(kStreamId, NotNull(), NotNull()));
     EXPECT_CALL(mirroring_manager_,
                 AddDiverter(kRenderProcessId, kRenderFrameId, NotNull()));
+    EXPECT_CALL(*stream_registry_, RegisterOutputStream(NotNull()));
     EXPECT_CALL(mirroring_manager_, RemoveDiverter(NotNull()));
+    EXPECT_CALL(*stream_registry_, DeregisterOutputStream(NotNull()));
 
     AudioOutputDelegate::UniquePtr delegate = AudioOutputDelegate::Create(
-        &event_handler_, audio_manager_.get(),
+        &event_handler_, stream_registry_.get(), audio_manager_.get(),
         log_factory_.CreateAudioLog(
             media::AudioLogFactory::AUDIO_OUTPUT_CONTROLLER),
         &mirroring_manager_, &media_observer_, kStreamId, kRenderFrameId,
         kRenderProcessId, audio_manager_->GetDefaultOutputStreamParameters(),
         kDefaultDeviceId);
     SyncWithAllThreads();
 
     delegate->controller()->OnError(nullptr);
     delegate.reset();
     SyncWithAllThreads();
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, done);
   }
 
  protected:
   // MediaStreamManager uses a DestructionObserver, so it must outlive the
   // TestBrowserThreadBundle.
   std::unique_ptr<MediaStreamManager> media_stream_manager_;
   std::unique_ptr<TestBrowserThreadBundle> thread_bundle_;
   std::unique_ptr<AudioManagerThread> audio_thread_;
   media::ScopedAudioManagerPtr audio_manager_;
   StrictMock<MockAudioMirroringManager> mirroring_manager_;
   StrictMock<MockEventHandler> event_handler_;
   StrictMock<MockObserver> media_observer_;
+  std::unique_ptr<MockAudioStreamRegistry, BrowserThread::DeleteOnIOThread>
+      stream_registry_;
   media::FakeAudioLogFactory log_factory_;
 
  private:
   void SyncWithAllThreads() {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
     // New tasks might be posted while we are syncing, but in every iteration at
     // least one task will be run. 20 iterations should be enough for our code.
     for (int i = 0; i < 20; ++i) {
       {
         base::MessageLoop::ScopedNestableTaskAllower allower(
@@ skipping 104 matching lines @@
 TEST_F(AudioOutputDelegateTest, ErrorAndDestroy) {
   base::RunLoop l;
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&AudioOutputDelegateTest::PlayAndDestroyTest,
                  base::Unretained(this), l.QuitClosure()));
   l.Run();
 }
 
 }  // namespace content