Revert r21137 to fix Chromium mac valgrind

TBR=scherkus

Review URL: http://codereview.chromium.org/159122

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21154 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 190 insertions, 188 deletions

diff --git a/media/audio/audio_output.h b/media/audio/audio_output.h
index a12742e..4793e71 100644
--- a/media/audio/audio_output.h
+++ b/media/audio/audio_output.h
@@ -91,7 +91,9 @@ class AudioOutputStream {
 
   // Starts playing audio and generating AudioSourceCallback::OnMoreData().
   // Since implementor of AudioOutputStream may have internal buffers, right
-  // after calling this method initial buffers are fetched.
+  // after calling this method initial buffers are fetched. User of this
+  // object should prepare |AudioOutputStream::GetNumBuffers()| before calling
+  // AudioOutputStream::Start().
   //
   // The output stream does not take ownership of this callback.
   virtual void Start(AudioSourceCallback* callback) = 0;
@@ -112,6 +114,11 @@ class AudioOutputStream {
   // After calling this method, the object should not be used anymore.
   virtual void Close() = 0;
 
+  // Gets the number of internal buffers used in this output stream. This
+  // method is useful for providing information about how user of this object
+  // should prepare initial buffers before calling AudioOutputStream::Start().
+  virtual size_t GetNumBuffers() = 0;
+
  protected:
   virtual ~AudioOutputStream() {}
 };
@@ -157,6 +164,11 @@ class AudioManager {
   virtual void MuteAll() = 0;
   virtual void UnMuteAll() = 0;
 
+  // For testing purposes only. Returns the internal buffer of the last
+  // AUDIO_MOCK AudioOutputStream closed. Returns NULL if none closed yet.
+  // The buffer size is the same as passed to AudioOutputStream::Open().
+  virtual const void* GetLastMockBuffer() = 0;
+
   // Get AudioManager singleton.
   // TODO(cpu): Define threading requirements for interacting with AudioManager.
   static AudioManager* GetAudioManager();
diff --git a/media/audio/fake_audio_output_stream.cc b/media/audio/fake_audio_output_stream.cc
index 6eb5417..e69de29 100644
--- a/media/audio/fake_audio_output_stream.cc
+++ b/media/audio/fake_audio_output_stream.cc
@@ -1,72 +0,0 @@
-// Copyright (c) 2009 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 "base/at_exit.h"
-#include "media/audio/fake_audio_output_stream.h"
-
-bool FakeAudioOutputStream::has_created_fake_stream_ = false;
-FakeAudioOutputStream* FakeAudioOutputStream::last_fake_stream_ = NULL;
-
-// static
-AudioOutputStream* FakeAudioOutputStream::MakeFakeStream() {
-  if (!has_created_fake_stream_)
-    base::AtExitManager::RegisterCallback(&DestroyLastFakeStream, NULL);
-  has_created_fake_stream_ = true;
-
-  return new FakeAudioOutputStream();
-}
-
-// static
-FakeAudioOutputStream* FakeAudioOutputStream::GetLastFakeStream() {
-  return last_fake_stream_;
-}
-
-bool FakeAudioOutputStream::Open(size_t packet_size) {
-  if (packet_size < sizeof(int16))
-    return false;
-  packet_size_ = packet_size;
-  buffer_.reset(new char[packet_size_]);
-  return true;
-}
-
-void FakeAudioOutputStream::Start(AudioSourceCallback* callback)  {
-  callback_ = callback;
-  memset(buffer_.get(), 0, packet_size_);
-  callback_->OnMoreData(this, buffer_.get(), packet_size_);
-}
-
-void FakeAudioOutputStream::Stop() {
-}
-
-void FakeAudioOutputStream::SetVolume(double left_level, double right_level) {
-  left_volume_ = left_level;
-  right_volume_ = right_level;
-}
-
-void FakeAudioOutputStream::GetVolume(double* left_level, double* right_level) {
-  *left_level = left_volume_;
-  *right_level = right_volume_;
-}
-
-void FakeAudioOutputStream::Close() {
-  callback_->OnClose(this);
-  callback_ = NULL;
-
-  if (last_fake_stream_)
-    delete last_fake_stream_;
-  last_fake_stream_ = this;
-}
-
-FakeAudioOutputStream::FakeAudioOutputStream()
-    : left_volume_(0),
-      right_volume_(0),
-      callback_(NULL),
-      packet_size_(0) {
-}
-
-// static
-void FakeAudioOutputStream::DestroyLastFakeStream(void* param) {
-  if (last_fake_stream_)
-    delete last_fake_stream_;
-}
diff --git a/media/audio/fake_audio_output_stream.h b/media/audio/fake_audio_output_stream.h
index 189a7ad..e69de29 100644
--- a/media/audio/fake_audio_output_stream.h
+++ b/media/audio/fake_audio_output_stream.h
@@ -1,50 +0,0 @@
-// Copyright (c) 2009 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.
-//
-// A fake implementation of AudioOutputStream. It is used for testing purpose.
-// TODO(hclam): Implement a thread in this fake output stream to simulate an
-// audio output stream reading from AudioSourceCallback.
-
-#ifndef MEDIA_AUDIO_FAKE_AUDIO_OUTPUT_STREAM_H_
-#define MEDIA_AUDIO_FAKE_AUDIO_OUTOUT_STREAM_H_
-
-#include <vector>
-
-#include "base/scoped_ptr.h"
-#include "media/audio/audio_output.h"
-
-class FakeAudioOutputStream : public AudioOutputStream {
- public:
-  static AudioOutputStream* MakeFakeStream();
-  static FakeAudioOutputStream* GetLastFakeStream();
-
-  virtual bool Open(size_t packet_size);
-  virtual void Start(AudioSourceCallback* callback);
-  virtual void Stop();
-  virtual void SetVolume(double left_level, double right_level);
-  virtual void GetVolume(double* left_level, double* right_level);
-  virtual void Close();
-
-  char* buffer() { return buffer_.get(); }
-  double left_volume() { return left_volume_; }
-  double right_volume() { return right_volume_; }
-
- private:
-  FakeAudioOutputStream();
-  virtual ~FakeAudioOutputStream() {}
-
-  static void DestroyLastFakeStream(void* param);
-  static bool has_created_fake_stream_;
-  static FakeAudioOutputStream* last_fake_stream_;
-
-  double left_volume_;
-  double right_volume_;
-  AudioSourceCallback* callback_;
-  scoped_ptr_malloc<char> buffer_;
-  size_t packet_size_;
-
-  DISALLOW_COPY_AND_ASSIGN(FakeAudioOutputStream);
-};
-
-#endif  // MEDIA_AUDIO_FAKE_AUDIO_OUTPUT_STREAM_H_
diff --git a/media/audio/linux/alsa_output.cc b/media/audio/linux/alsa_output.cc
index 08075de..e7dab51 100644
--- a/media/audio/linux/alsa_output.cc
+++ b/media/audio/linux/alsa_output.cc
@@ -527,3 +527,7 @@ void AlsaPCMOutputStream::SetVolume(double left_level, double right_level) {
 void AlsaPCMOutputStream::GetVolume(double* left_level, double* right_level) {
   NOTIMPLEMENTED();
 }
+
+size_t AlsaPCMOutputStream::GetNumBuffers() {
+  return 0;
+}
diff --git a/media/audio/linux/alsa_output.h b/media/audio/linux/alsa_output.h
index 850ab7f..42cd3c8 100644
--- a/media/audio/linux/alsa_output.h
+++ b/media/audio/linux/alsa_output.h
@@ -65,6 +65,7 @@ class AlsaPCMOutputStream :
   virtual void Stop();
   virtual void SetVolume(double left_level, double right_level);
   virtual void GetVolume(double* left_level, double* right_level);
+  virtual size_t GetNumBuffers();
 
  private:
   // Closes the playback handle, reporting errors if any occur.  Returns true
diff --git a/media/audio/linux/audio_manager_linux.cc b/media/audio/linux/audio_manager_linux.cc
index a9d299f..69e8b9b 100644
--- a/media/audio/linux/audio_manager_linux.cc
+++ b/media/audio/linux/audio_manager_linux.cc
@@ -6,7 +6,6 @@
 
 #include "base/at_exit.h"
 #include "base/logging.h"
-#include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/linux/alsa_output.h"
 
 namespace {
@@ -28,15 +27,11 @@ AudioOutputStream* AudioManagerLinux::MakeAudioStream(Format format,
   // surround40, surround51, etc.
   //
   // http://0pointer.de/blog/projects/guide-to-sound-apis.html
-  if (format == AudioManager::AUDIO_MOCK) {
-    return FakeAudioOutputStream::MakeFakeStream();
-  } else {
-    AlsaPCMOutputStream* stream =
-        new AlsaPCMOutputStream(AlsaPCMOutputStream::kDefaultDevice,
-                                100 /* 100ms minimal buffer */,
-                                format, channels, sample_rate, bits_per_sample);
-    return stream;
-  }
+  AlsaPCMOutputStream* stream =
+      new AlsaPCMOutputStream(AlsaPCMOutputStream::kDefaultDevice,
+                              100 /* 100ms minimal buffer */,
+                              format, channels, sample_rate, bits_per_sample);
+  return stream;
 }
 
 AudioManagerLinux::AudioManagerLinux() {
@@ -55,6 +50,12 @@ void AudioManagerLinux::UnMuteAll() {
   NOTIMPLEMENTED();
 }
 
+const void* AudioManagerLinux::GetLastMockBuffer() {
+  // TODO(ajwong): Implement.
+  NOTIMPLEMENTED();
+  return NULL;
+}
+
 // TODO(ajwong): Collapse this with the windows version.
 void DestroyAudioManagerLinux(void* not_used) {
   delete g_audio_manager;
diff --git a/media/audio/linux/audio_manager_linux.h b/media/audio/linux/audio_manager_linux.h
index 191e687..5b369a1 100644
--- a/media/audio/linux/audio_manager_linux.h
+++ b/media/audio/linux/audio_manager_linux.h
@@ -19,6 +19,7 @@ class AudioManagerLinux : public AudioManager {
                                              char bits_per_sample);
   virtual void MuteAll();
   virtual void UnMuteAll();
+  virtual const void* GetLastMockBuffer();
 
  private:
   // Friend function for invoking the private destructor at exit.
diff --git a/media/audio/mac/audio_manager_mac.cc b/media/audio/mac/audio_manager_mac.cc
index a921dfb..7a8e15b 100644
--- a/media/audio/mac/audio_manager_mac.cc
+++ b/media/audio/mac/audio_manager_mac.cc
@@ -5,7 +5,6 @@
 #include <CoreAudio/AudioHardware.h>
 
 #include "base/at_exit.h"
-#include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/audio/mac/audio_output_mac.h"
 
@@ -20,9 +19,8 @@ bool AudioManagerMac::HasAudioDevices() {
 AudioOutputStream* AudioManagerMac::MakeAudioStream(Format format, int channels,
                                                     int sample_rate,
                                                     char bits_per_sample) {
-  if (format == AUDIO_MOCK)
-    return FakeAudioOutputStream::MakeFakeStream();
-  else if (format != AUDIO_PCM_LINEAR)
+  // TODO(cpu): add mock format.
+  if (format != AUDIO_PCM_LINEAR)
     return NULL;
   return new PCMQueueOutAudioOutputStream(this, channels, sample_rate,
                                           bits_per_sample);
@@ -36,15 +34,19 @@ void AudioManagerMac::UnMuteAll() {
   // TODO(cpu): implement.
 }
 
+const void* AudioManagerMac::GetLastMockBuffer() {
+  // TODO(cpu): implement.
+  return NULL;
+}
+
 // Called by the stream when it has been released by calling Close().
 void AudioManagerMac::ReleaseStream(PCMQueueOutAudioOutputStream* stream) {
   delete stream;
 }
 
 namespace {
-
-AudioManagerMac* g_audio_manager = NULL;
-
+  AudioManagerMac* g_audio_manager = NULL;
+  
 }  // namespace.
 
 void DestroyAudioManagerMac(void* param) {
diff --git a/media/audio/mac/audio_manager_mac.h b/media/audio/mac/audio_manager_mac.h
index 51ee58a..46cb2a5 100644
--- a/media/audio/mac/audio_manager_mac.h
+++ b/media/audio/mac/audio_manager_mac.h
@@ -24,6 +24,7 @@ class AudioManagerMac : public AudioManager {
                                              char bits_per_sample);
   virtual void MuteAll();
   virtual void UnMuteAll();
+  virtual const void* GetLastMockBuffer();
 
   // Mac-only method to free a stream created in MakeAudioStream.
   // It is called internally by the audio stream when it has been closed.
diff --git a/media/audio/mac/audio_output_mac.cc b/media/audio/mac/audio_output_mac.cc
index 657e91a..4d7c6bb 100644
--- a/media/audio/mac/audio_output_mac.cc
+++ b/media/audio/mac/audio_output_mac.cc
@@ -145,6 +145,10 @@ void PCMQueueOutAudioOutputStream::GetVolume(double* left_level,
   // TODO(cpu): Implement.
 }
 
+size_t PCMQueueOutAudioOutputStream::GetNumBuffers() {
+  return kNumBuffers;
+}
+
 // Note to future hackers of this function: Do not add locks here because we
 // call out to third party source that might do crazy things including adquire
 // external locks or somehow re-enter here because its legal for them to call
diff --git a/media/audio/mac/audio_output_mac.h b/media/audio/mac/audio_output_mac.h
index 340e1eb..d1129b3 100644
--- a/media/audio/mac/audio_output_mac.h
+++ b/media/audio/mac/audio_output_mac.h
@@ -35,6 +35,7 @@ class PCMQueueOutAudioOutputStream : public AudioOutputStream {
   virtual void Stop();
   virtual void SetVolume(double left_level, double right_level);
   virtual void GetVolume(double* left_level, double* right_level);
+  virtual size_t GetNumBuffers();
 
  private:
   // The audio is double buffered.
diff --git a/media/audio/simple_sources_unittest.cc b/media/audio/simple_sources_unittest.cc
index ef6a5a7..32176b7 100644
--- a/media/audio/simple_sources_unittest.cc
+++ b/media/audio/simple_sources_unittest.cc
@@ -6,7 +6,6 @@
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
 #include "base/time.h"
-#include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/simple_sources.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -61,48 +60,3 @@ TEST(SimpleSourcesTest, PushSourceSmallerWrite) {
 
   push_source.OnClose(NULL);
 }
-
-// Validate that the SineWaveAudioSource writes the expected values for
-// the FORMAT_16BIT_MONO. The values are carefully selected so rounding issues
-// do not affect the result. We also test that AudioManager::GetLastMockBuffer
-// works.
-TEST(SimpleSources, SineWaveAudio16MonoTest) {
-  const size_t samples = 1024;
-  const size_t bytes_per_sample = 2;
-  const int freq = 200;
-
-  SineWaveAudioSource source(SineWaveAudioSource::FORMAT_16BIT_LINEAR_PCM, 1,
-                             freq, AudioManager::kTelephoneSampleRate);
-
-  AudioManager* audio_man = AudioManager::GetAudioManager();
-  ASSERT_TRUE(NULL != audio_man);
-  AudioOutputStream* oas =
-      audio_man->MakeAudioStream(AudioManager::AUDIO_MOCK, 1,
-                                 AudioManager::kTelephoneSampleRate,
-                                 bytes_per_sample * 2);
-  ASSERT_TRUE(NULL != oas);
-  EXPECT_TRUE(oas->Open(samples * bytes_per_sample));
-
-  oas->Start(&source);
-  oas->Stop();
-  oas->Close();
-
-  ASSERT_TRUE(FakeAudioOutputStream::GetLastFakeStream());
-  const int16* last_buffer =
-      reinterpret_cast<int16*>(
-          FakeAudioOutputStream::GetLastFakeStream()->buffer());
-  ASSERT_TRUE(NULL != last_buffer);
-
-  size_t half_period = AudioManager::kTelephoneSampleRate / (freq * 2);
-
-  // Spot test positive incursion of sine wave.
-  EXPECT_EQ(0, last_buffer[0]);
-  EXPECT_EQ(5126, last_buffer[1]);
-  EXPECT_TRUE(last_buffer[1] < last_buffer[2]);
-  EXPECT_TRUE(last_buffer[2] < last_buffer[3]);
-  // Spot test negative incursion of sine wave.
-  EXPECT_EQ(0, last_buffer[half_period]);
-  EXPECT_EQ(-5126, last_buffer[half_period + 1]);
-  EXPECT_TRUE(last_buffer[half_period + 1] > last_buffer[half_period + 2]);
-  EXPECT_TRUE(last_buffer[half_period + 2] > last_buffer[half_period + 3]);
-}
diff --git a/media/audio/win/audio_manager_win.h b/media/audio/win/audio_manager_win.h
index f060fc4..12a4c06 100644
--- a/media/audio/win/audio_manager_win.h
+++ b/media/audio/win/audio_manager_win.h
@@ -11,6 +11,7 @@
 #include "media/audio/audio_output.h"
 
 class PCMWaveOutAudioOutputStream;
+class AudioOutputStreamMockWin;
 
 // Windows implementation of the AudioManager singleton. This class is internal
 // to the audio output and only internal users can call methods not exposed by
@@ -25,10 +26,12 @@ class AudioManagerWin : public AudioManager {
                                              char bits_per_sample);
   virtual void MuteAll();
   virtual void UnMuteAll();
+  virtual const void* GetLastMockBuffer();
 
   // Windows-only methods to free a stream created in MakeAudioStream. These
   // are called internally by the audio stream when it has been closed.
   void ReleaseStream(PCMWaveOutAudioOutputStream* stream);
+  void ReleaseStream(AudioOutputStreamMockWin* stream);
 
  private:
   friend void DestroyAudioManagerWin(void *);
diff --git a/media/audio/win/audio_output_win.cc b/media/audio/win/audio_output_win.cc
index f7eac01..bc8c712 100644
--- a/media/audio/win/audio_output_win.cc
+++ b/media/audio/win/audio_output_win.cc
@@ -9,10 +9,81 @@
 
 #include "base/at_exit.h"
 #include "base/basictypes.h"
-#include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/win/audio_manager_win.h"
 #include "media/audio/win/waveout_output_win.h"
 
+// A do-nothing audio stream. It behaves like a regular audio stream but does
+// not have any side effect, except possibly the creation and tear-down of
+// of a thread. It is useful to test code that uses audio streams such as
+// audio sources.
+class AudioOutputStreamMockWin : public AudioOutputStream {
+ public:
+  explicit AudioOutputStreamMockWin(AudioManagerWin* manager)
+      : manager_(manager),
+        callback_(NULL),
+        buffer_(NULL),
+        packet_size_(0),
+        left_volume_(1.0),
+        right_volume_(1.0) {
+  }
+
+  virtual ~AudioOutputStreamMockWin() {
+    delete[] buffer_;
+    packet_size_ = 0;
+  }
+
+  virtual bool Open(size_t packet_size) {
+    if (packet_size < sizeof(int16))
+      return false;
+    packet_size_ = packet_size;
+    buffer_ = new char[packet_size_];
+    return true;
+  }
+
+  virtual void Start(AudioSourceCallback* callback)  {
+    callback_ = callback;
+    memset(buffer_, 0, packet_size_);
+    callback_->OnMoreData(this, buffer_, packet_size_);
+  }
+
+  // TODO(cpu): flesh out Start and Stop methods. We need a thread to
+  // perform periodic callbacks.
+  virtual void Stop() {
+  }
+
+  virtual void SetVolume(double left_level, double right_level) {
+    left_volume_ = left_level;
+    right_volume_ = right_level;
+  }
+
+  virtual void GetVolume(double* left_level, double* right_level) {
+    *left_level = left_volume_;
+    *right_level = right_volume_;
+  }
+
+  virtual size_t GetNumBuffers() {
+    return 1;
+  }
+
+  virtual void Close() {
+    callback_->OnClose(this);
+    callback_ = NULL;
+    manager_->ReleaseStream(this);
+  }
+
+  char* buffer() {
+    return buffer_;
+  }
+
+ private:
+  AudioManagerWin* manager_;
+  AudioSourceCallback* callback_;
+  char* buffer_;
+  size_t packet_size_;
+  double left_volume_;
+  double right_volume_;
+};
+
 namespace {
 
 // The next 3 constants are some sensible limits to prevent integer overflow
@@ -31,10 +102,18 @@ const int kMaxChannels = 6;
 const int kMaxSampleRate = 192000;
 const int kMaxBitsPerSample = 64;
 
+AudioOutputStreamMockWin* g_last_mock_stream = NULL;
 AudioManagerWin* g_audio_manager = NULL;
 
+void ReplaceLastMockStream(AudioOutputStreamMockWin* newer) {
+  if (g_last_mock_stream)
+    delete g_last_mock_stream;
+  g_last_mock_stream = newer;
+}
+
 }  // namespace.
 
+
 bool AudioManagerWin::HasAudioDevices() {
   return (::waveOutGetNumDevs() != 0);
 }
@@ -43,6 +122,7 @@ bool AudioManagerWin::HasAudioDevices() {
 // should suffice most windows user's needs.
 // - PCMWaveOutAudioOutputStream: Based on the waveOutWrite API (in progress)
 // - PCMDXSoundAudioOutputStream: Based on DirectSound or XAudio (future work).
+
 AudioOutputStream* AudioManagerWin::MakeAudioStream(Format format, int channels,
                                                     int sample_rate,
                                                     char bits_per_sample) {
@@ -52,7 +132,7 @@ AudioOutputStream* AudioManagerWin::MakeAudioStream(Format format, int channels,
     return NULL;
 
   if (format == AUDIO_MOCK) {
-    return FakeAudioOutputStream::MakeFakeStream();
+    return new AudioOutputStreamMockWin(this);
   } else if (format == AUDIO_PCM_LINEAR) {
     return new PCMWaveOutAudioOutputStream(this, channels, sample_rate,
                                            bits_per_sample, WAVE_MAPPER);
@@ -65,6 +145,15 @@ void AudioManagerWin::ReleaseStream(PCMWaveOutAudioOutputStream* stream) {
     delete stream;
 }
 
+void AudioManagerWin::ReleaseStream(AudioOutputStreamMockWin *stream) {
+  // Note that we keep the last mock stream so GetLastMockBuffer() works.
+  ReplaceLastMockStream(stream);
+}
+
+const void* AudioManagerWin::GetLastMockBuffer() {
+  return (g_last_mock_stream) ? g_last_mock_stream->buffer() : NULL;
+}
+
 void AudioManagerWin::MuteAll() {
 }
 
@@ -72,6 +161,7 @@ void AudioManagerWin::UnMuteAll() {
 }
 
 AudioManagerWin::~AudioManagerWin() {
+  ReplaceLastMockStream(NULL);
 }
 
 void DestroyAudioManagerWin(void* param) {
diff --git a/media/audio/win/audio_output_win_unittest.cc b/media/audio/win/audio_output_win_unittest.cc
index f47bd9c..fae74ac 100644
--- a/media/audio/win/audio_output_win_unittest.cc
+++ b/media/audio/win/audio_output_win_unittest.cc
@@ -193,6 +193,51 @@ TEST(WinAudioTest, MockStreamBasicCallbacks) {
   EXPECT_EQ(1, source.was_closed());
 }
 
+// Validate that the SineWaveAudioSource writes the expected values for
+// the FORMAT_16BIT_MONO. The values are carefully selected so rounding issues
+// do not affect the result. We also test that AudioManager::GetLastMockBuffer
+// works.
+// TODO(hclam): move this test to SimpleSourcesTest once mock audio stream is
+// implemented on other platform.
+TEST(WinAudioTest, SineWaveAudio16MonoTest) {
+  const size_t samples = 1024;
+  const size_t bytes_per_sample = 2;
+  const int freq = 200;
+
+  SineWaveAudioSource source(SineWaveAudioSource::FORMAT_16BIT_LINEAR_PCM, 1,
+                             freq, AudioManager::kTelephoneSampleRate);
+
+  AudioManager* audio_man = AudioManager::GetAudioManager();
+  ASSERT_TRUE(NULL != audio_man);
+  AudioOutputStream* oas =
+      audio_man->MakeAudioStream(AudioManager::AUDIO_MOCK, 1,
+                                 AudioManager::kTelephoneSampleRate,
+                                 bytes_per_sample * 2);
+  ASSERT_TRUE(NULL != oas);
+  EXPECT_TRUE(oas->Open(samples * bytes_per_sample));
+
+  oas->Start(&source);
+  oas->Stop();
+  oas->Close();
+
+  const int16* last_buffer =
+      reinterpret_cast<const int16*>(audio_man->GetLastMockBuffer());
+  ASSERT_TRUE(NULL != last_buffer);
+
+  size_t half_period = AudioManager::kTelephoneSampleRate / (freq * 2);
+
+  // Spot test positive incursion of sine wave.
+  EXPECT_EQ(0, last_buffer[0]);
+  EXPECT_EQ(5126, last_buffer[1]);
+  EXPECT_TRUE(last_buffer[1] < last_buffer[2]);
+  EXPECT_TRUE(last_buffer[2] < last_buffer[3]);
+  // Spot test negative incursion of sine wave.
+  EXPECT_EQ(0, last_buffer[half_period]);
+  EXPECT_EQ(-5126, last_buffer[half_period + 1]);
+  EXPECT_TRUE(last_buffer[half_period + 1] > last_buffer[half_period + 2]);
+  EXPECT_TRUE(last_buffer[half_period + 2] > last_buffer[half_period + 3]);
+}
+
 // ===========================================================================
 // Validation of AudioManager::AUDIO_PCM_LINEAR
 //
diff --git a/media/audio/win/waveout_output_win.cc b/media/audio/win/waveout_output_win.cc
index 124d8e7..d8d2ebdd 100644
--- a/media/audio/win/waveout_output_win.cc
+++ b/media/audio/win/waveout_output_win.cc
@@ -215,6 +215,10 @@ void PCMWaveOutAudioOutputStream::GetVolume(double* left_level,
   *right_level = volume_;
 }
 
+size_t PCMWaveOutAudioOutputStream::GetNumBuffers() {
+  return kNumBuffers;
+}
+
 void PCMWaveOutAudioOutputStream::HandleError(MMRESULT error) {
   DLOG(WARNING) << "PCMWaveOutAudio error " << error;
   callback_->OnError(this, error);
diff --git a/media/audio/win/waveout_output_win.h b/media/audio/win/waveout_output_win.h
index 3f822e9..ea9bdef 100644
--- a/media/audio/win/waveout_output_win.h
+++ b/media/audio/win/waveout_output_win.h
@@ -40,6 +40,7 @@ class PCMWaveOutAudioOutputStream : public AudioOutputStream {
   virtual void Stop();
   virtual void SetVolume(double left_level, double right_level);
   virtual void GetVolume(double* left_level, double* right_level);
+  virtual size_t GetNumBuffers();
 
   // Sends a buffer to the audio driver for playback.
   void QueueNextPacket(WAVEHDR* buffer);