Reland: "Support audio channel count and sample rate changes on Windows."

Includes one line fix in audio_device_listener_win.cc to use the
DCHECK_CALLED_ON_VALID_THREAD() macro.

----- [ Original Description ] -----

This fixes a TODO in AudioDeviceListenerWin on listening for
property value changes... by listening for them in a completely
different way.

Unfortunately forcing mono audio for accessibility doesn't
generate IMMNotificationClient events, so we need to instead
use the IAudioSessionEvents interface, but that can only be
hung off a fully initialized IAudioClient... which is only
done during WASAPI audio output setup.

So the original TODO is fixed by adding a 1-to-1 path for device
changes (in addition to the 1-to-many path). We still need both
paths since just switching your default device won't generate an
IAudioSessionEvent notification, only an IMMNotificationClient
event. Additionally fake and WaveOut based devices don't have a
IAudioSessionEvents interface, so still need the old path.

Misc other cleanups:
- Expands the AudioDeviceListenerWin unit tests.
- Fixes broken --force-wave-audio switch in AudioManagerWin.

BUG=1020006
TEST=property changes, mono audio changes, default changes work.
TBR=henrika, tguilbert

Change-Id: I95f5f439982a68d2b509db10978a570fb98081b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1931408Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718374}

media/audio/BUILD.gn

@@ -195,6 +195,8 @@ source_set("audio") {
       "win/audio_low_latency_output_win.h",
       "win/audio_manager_win.cc",
       "win/audio_manager_win.h",
+      "win/audio_session_event_listener_win.cc",
+      "win/audio_session_event_listener_win.h",
       "win/avrt_wrapper_win.cc",
       "win/avrt_wrapper_win.h",
       "win/core_audio_util_win.cc",
@@ -441,6 +443,7 @@ source_set("unit_tests") {
       "win/audio_low_latency_input_win_unittest.cc",
       "win/audio_low_latency_output_win_unittest.cc",
       "win/audio_output_win_unittest.cc",
+      "win/audio_session_event_listener_win_unittest.cc",
       "win/core_audio_util_win_unittest.cc",
       "win/device_enumeration_win_unittest.cc",
     ]

media/audio/win/audio_device_listener_win.cc

@@ -19,32 +19,38 @@ using base::win::ScopedCoMem;
 namespace media {
 
 static std::string FlowToString(EDataFlow flow) {
-  return (flow == eRender) ? "eRender" : "eConsole";
+  return flow == eRender ? "eRender" : "eConsole";
 }
 
 static std::string RoleToString(ERole role) {
   switch (role) {
-    case eConsole: return "eConsole";
-    case eMultimedia: return "eMultimedia";
-    case eCommunications: return "eCommunications";
-    default: return "undefined";
+    case eConsole:
+      return "eConsole";
+    case eMultimedia:
+      return "eMultimedia";
+    case eCommunications:
+      return "eCommunications";
+    default:
+      return "undefined";
   }
 }
 
-AudioDeviceListenerWin::AudioDeviceListenerWin(const base::Closure& listener_cb)
-    : listener_cb_(listener_cb),
+AudioDeviceListenerWin::AudioDeviceListenerWin(
+    base::RepeatingClosure listener_cb)
+    : listener_cb_(std::move(listener_cb)),
       tick_clock_(base::DefaultTickClock::GetInstance()) {
   // CreateDeviceEnumerator can fail on some installations of Windows such
   // as "Windows Server 2008 R2" where the desktop experience isn't available.
-  Microsoft::WRL::ComPtr<IMMDeviceEnumerator> device_enumerator(
-      CoreAudioUtil::CreateDeviceEnumerator());
-  if (!device_enumerator.Get())
+  auto device_enumerator = CoreAudioUtil::CreateDeviceEnumerator();
+  if (!device_enumerator) {
+    DLOG(ERROR) << "Failed to create device enumeration.";
     return;
+  }
 
   HRESULT hr = device_enumerator->RegisterEndpointNotificationCallback(this);
   if (FAILED(hr)) {
-    LOG(ERROR)  << "RegisterEndpointNotificationCallback failed: "
-                << std::hex << hr;
+    DLOG(ERROR) << "RegisterEndpointNotificationCallback failed: " << std::hex
+                << hr;
     return;
   }
 
@@ -52,13 +58,13 @@ AudioDeviceListenerWin::AudioDeviceListenerWin(const base::Closure& listener_cb)
 }
 
 AudioDeviceListenerWin::~AudioDeviceListenerWin() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  if (device_enumerator_.Get()) {
-    HRESULT hr =
-        device_enumerator_->UnregisterEndpointNotificationCallback(this);
-    LOG_IF(ERROR, FAILED(hr)) << "UnregisterEndpointNotificationCallback() "
-                              << "failed: " << std::hex << hr;
-  }
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  if (!device_enumerator_)
+    return;
+
+  HRESULT hr = device_enumerator_->UnregisterEndpointNotificationCallback(this);
+  DLOG_IF(ERROR, FAILED(hr)) << "UnregisterEndpointNotificationCallback() "
+                             << "failed: " << std::hex << hr;
 }
 
 STDMETHODIMP_(ULONG) AudioDeviceListenerWin::AddRef() {
@@ -75,15 +81,16 @@ STDMETHODIMP AudioDeviceListenerWin::QueryInterface(REFIID iid, void** object) {
     return S_OK;
   }
 
-  *object = NULL;
+  *object = nullptr;
   return E_NOINTERFACE;
 }
 
 STDMETHODIMP AudioDeviceListenerWin::OnPropertyValueChanged(
-    LPCWSTR device_id, const PROPERTYKEY key) {
-  // TODO(dalecurtis): We need to handle changes for the current default device
-  // here.  It's tricky because this method may be called many (20+) times for
-  // a single change like sample rate.  http://crbug.com/153056
+    LPCWSTR device_id,
+    const PROPERTYKEY key) {
+  // Property changes are handled by IAudioSessionControl listeners hung off of
+  // each WASAPIAudioOutputStream() since not all property changes make it to
+  // this method and those that do are spammed 10s of times.
   return S_OK;
 }
 
@@ -99,15 +106,15 @@ STDMETHODIMP AudioDeviceListenerWin::OnDeviceRemoved(LPCWSTR device_id) {
 
 STDMETHODIMP AudioDeviceListenerWin::OnDeviceStateChanged(LPCWSTR device_id,
                                                           DWORD new_state) {
-  base::SystemMonitor* monitor = base::SystemMonitor::Get();
-  if (monitor)
+  if (auto* monitor = base::SystemMonitor::Get())
     monitor->ProcessDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO);
-
   return S_OK;
 }
 
 STDMETHODIMP AudioDeviceListenerWin::OnDefaultDeviceChanged(
-    EDataFlow flow, ERole role, LPCWSTR new_default_device_id) {
+    EDataFlow flow,
+    ERole role,
+    LPCWSTR new_default_device_id) {
   // Only listen for console and communication device changes.
   if ((role != eConsole && role != eCommunications) ||
       (flow != eRender && flow != eCapture)) {
@@ -128,16 +135,13 @@ STDMETHODIMP AudioDeviceListenerWin::OnDefaultDeviceChanged(
   // it provides a substantially faster resumption of playback.
   bool did_run_listener_cb = false;
   const base::TimeTicks now = tick_clock_->NowTicks();
-  if (flow == eRender &&
-      now - last_device_change_time_ >
-          base::TimeDelta::FromMilliseconds(kDeviceChangeLimitMs)) {
+  if (flow == eRender && now - last_device_change_time_ > kDeviceChangeLimit) {
     last_device_change_time_ = now;
     listener_cb_.Run();
     did_run_listener_cb = true;
   }
 
-  base::SystemMonitor* monitor = base::SystemMonitor::Get();
-  if (monitor)
+  if (auto* monitor = base::SystemMonitor::Get())
     monitor->ProcessDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO);
 
   DVLOG(1) << "OnDefaultDeviceChanged() "

media/audio/win/audio_device_listener_win.h

@@ -32,38 +32,38 @@ namespace media {
 class MEDIA_EXPORT AudioDeviceListenerWin : public IMMNotificationClient {
  public:
   // The listener callback will be called from a system level multimedia thread,
-  // thus the callee must be thread safe.  |listener| is a permanent callback
+  // thus the callee must be thread safe.  |listener_cb| is a permanent callback
   // and must outlive AudioDeviceListenerWin.
-  explicit AudioDeviceListenerWin(const base::Closure& listener_cb);
+  explicit AudioDeviceListenerWin(base::RepeatingClosure listener_cb);
   virtual ~AudioDeviceListenerWin();
 
  private:
   friend class AudioDeviceListenerWinTest;
 
   // Minimum allowed time between device change notifications.
-  static const int kDeviceChangeLimitMs = 250;
+  static constexpr base::TimeDelta kDeviceChangeLimit =
+      base::TimeDelta::FromMilliseconds(250);
 
   // IMMNotificationClient implementation.
   STDMETHOD_(ULONG, AddRef)() override;
   STDMETHOD_(ULONG, Release)() override;
   STDMETHOD(QueryInterface)(REFIID iid, void** object) override;
-  STDMETHOD(OnPropertyValueChanged)(LPCWSTR device_id,
-                                    const PROPERTYKEY key) override;
+  STDMETHOD(OnPropertyValueChanged)
+  (LPCWSTR device_id, const PROPERTYKEY key) override;
   STDMETHOD(OnDeviceAdded)(LPCWSTR device_id) override;
   STDMETHOD(OnDeviceRemoved)(LPCWSTR device_id) override;
   STDMETHOD(OnDeviceStateChanged)(LPCWSTR device_id, DWORD new_state) override;
-  STDMETHOD(OnDefaultDeviceChanged)(EDataFlow flow,
-                                    ERole role,
-                                    LPCWSTR new_default_device_id) override;
+  STDMETHOD(OnDefaultDeviceChanged)
+  (EDataFlow flow, ERole role, LPCWSTR new_default_device_id) override;
 
-  base::Closure listener_cb_;
+  const base::RepeatingClosure listener_cb_;
   Microsoft::WRL::ComPtr<IMMDeviceEnumerator> device_enumerator_;
 
   // Used to rate limit device change events.
   base::TimeTicks last_device_change_time_;
 
   // AudioDeviceListenerWin must be constructed and destructed on one thread.
-  base::ThreadChecker thread_checker_;
+  THREAD_CHECKER(thread_checker_);
 
   const base::TickClock* tick_clock_;
 

media/audio/win/audio_device_listener_win_unittest.cc

@@ -11,7 +11,9 @@
 #include "base/bind_helpers.h"
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/system/system_monitor.h"
 #include "base/test/simple_test_tick_clock.h"
+#include "base/test/task_environment.h"
 #include "base/win/scoped_com_initializer.h"
 #include "media/audio/audio_manager.h"
 #include "media/audio/audio_unittest_util.h"
@@ -23,51 +25,62 @@ using base::win::ScopedCOMInitializer;
 
 namespace media {
 
-static const char kFirstTestDevice[] = "test_device_0";
-static const char kSecondTestDevice[] = "test_device_1";
+constexpr char kFirstTestDevice[] = "test_device_0";
+constexpr char kSecondTestDevice[] = "test_device_1";
 
-class AudioDeviceListenerWinTest : public testing::Test {
+class AudioDeviceListenerWinTest
+    : public testing::Test,
+      public base::SystemMonitor::DevicesChangedObserver {
  public:
   AudioDeviceListenerWinTest() {
     DCHECK(com_init_.Succeeded());
-  }
-
-  virtual void SetUp() {
     if (!CoreAudioUtil::IsSupported())
       return;
 
-    output_device_listener_.reset(new AudioDeviceListenerWin(base::Bind(
-        &AudioDeviceListenerWinTest::OnDeviceChange, base::Unretained(this))));
+    system_monitor_.AddDevicesChangedObserver(this);
+
+    output_device_listener_ = std::make_unique<AudioDeviceListenerWin>(
+        base::BindRepeating(&AudioDeviceListenerWinTest::OnDeviceChange,
+                            base::Unretained(this)));
 
     tick_clock_.Advance(base::TimeDelta::FromSeconds(12345));
     output_device_listener_->tick_clock_ = &tick_clock_;
   }
 
+  ~AudioDeviceListenerWinTest() override {
+    system_monitor_.RemoveDevicesChangedObserver(this);
+  }
+
   void AdvanceLastDeviceChangeTime() {
-    tick_clock_.Advance(base::TimeDelta::FromMilliseconds(
-        AudioDeviceListenerWin::kDeviceChangeLimitMs + 1));
+    tick_clock_.Advance(AudioDeviceListenerWin::kDeviceChangeLimit +
+                        base::TimeDelta::FromMilliseconds(1));
   }
 
   // Simulate a device change where no output devices are available.
   bool SimulateNullDefaultOutputDeviceChange() {
-    return output_device_listener_->OnDefaultDeviceChanged(
-        static_cast<EDataFlow>(eConsole), static_cast<ERole>(eRender),
-        NULL) == S_OK;
+    auto result = output_device_listener_->OnDefaultDeviceChanged(
+        static_cast<EDataFlow>(eConsole), static_cast<ERole>(eRender), nullptr);
+    task_environment_.RunUntilIdle();
+    return result == S_OK;
   }
 
   bool SimulateDefaultOutputDeviceChange(const char* new_device_id) {
-    return output_device_listener_->OnDefaultDeviceChanged(
+    auto result = output_device_listener_->OnDefaultDeviceChanged(
         static_cast<EDataFlow>(eConsole), static_cast<ERole>(eRender),
-        base::ASCIIToUTF16(new_device_id).c_str()) == S_OK;
+        base::ASCIIToUTF16(new_device_id).c_str());
+    task_environment_.RunUntilIdle();
+    return result == S_OK;
   }
 
-
   MOCK_METHOD0(OnDeviceChange, void());
+  MOCK_METHOD1(OnDevicesChanged, void(base::SystemMonitor::DeviceType));
 
  private:
   ScopedCOMInitializer com_init_;
-  std::unique_ptr<AudioDeviceListenerWin> output_device_listener_;
+  base::test::TaskEnvironment task_environment_;
+  base::SystemMonitor system_monitor_;
   base::SimpleTestTickClock tick_clock_;
+  std::unique_ptr<AudioDeviceListenerWin> output_device_listener_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioDeviceListenerWinTest);
 };
@@ -77,14 +90,22 @@ TEST_F(AudioDeviceListenerWinTest, OutputDeviceChange) {
   ABORT_AUDIO_TEST_IF_NOT(CoreAudioUtil::IsSupported());
 
   EXPECT_CALL(*this, OnDeviceChange()).Times(1);
+  EXPECT_CALL(*this, OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO))
+      .Times(1);
   ASSERT_TRUE(SimulateDefaultOutputDeviceChange(kFirstTestDevice));
 
   testing::Mock::VerifyAndClear(this);
   AdvanceLastDeviceChangeTime();
   EXPECT_CALL(*this, OnDeviceChange()).Times(1);
+  EXPECT_CALL(*this, OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO))
+      .Times(1);
   ASSERT_TRUE(SimulateDefaultOutputDeviceChange(kSecondTestDevice));
 
-  // The second device event should be ignored since it occurs too soon.
+  // Since it occurs too soon, the second device event shouldn't call
+  // OnDeviceChange(), but it should notify OnDevicesChanged().
+  EXPECT_CALL(*this, OnDeviceChange()).Times(0);
+  EXPECT_CALL(*this, OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO))
+      .Times(1);
   ASSERT_TRUE(SimulateDefaultOutputDeviceChange(kSecondTestDevice));
 }
 
@@ -94,16 +115,22 @@ TEST_F(AudioDeviceListenerWinTest, NullOutputDeviceChange) {
   ABORT_AUDIO_TEST_IF_NOT(CoreAudioUtil::IsSupported());
 
   EXPECT_CALL(*this, OnDeviceChange()).Times(1);
+  EXPECT_CALL(*this, OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO))
+      .Times(1);
   ASSERT_TRUE(SimulateNullDefaultOutputDeviceChange());
 
   testing::Mock::VerifyAndClear(this);
   AdvanceLastDeviceChangeTime();
   EXPECT_CALL(*this, OnDeviceChange()).Times(1);
+  EXPECT_CALL(*this, OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO))
+      .Times(1);
   ASSERT_TRUE(SimulateDefaultOutputDeviceChange(kFirstTestDevice));
 
+  // Since it occurs too soon, the second device event shouldn't call
+  // OnDeviceChange(), but it should notify OnDevicesChanged().
   testing::Mock::VerifyAndClear(this);
-  AdvanceLastDeviceChangeTime();
-  EXPECT_CALL(*this, OnDeviceChange()).Times(1);
+  EXPECT_CALL(*this, OnDevicesChanged(base::SystemMonitor::DEVTYPE_AUDIO))
+      .Times(1);
   ASSERT_TRUE(SimulateNullDefaultOutputDeviceChange());
 }
 

media/audio/win/audio_low_latency_output_win.cc

@@ -5,10 +5,12 @@
 #include "media/audio/win/audio_low_latency_output_win.h"
 
 #include <Functiondiscoverykeys_devpkey.h>
+#include <audiopolicy.h>
 #include <objbase.h>
 
 #include <climits>
 
+#include "base/callback.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ -20,9 +22,11 @@
 #include "base/win/scoped_propvariant.h"
 #include "media/audio/audio_device_description.h"
 #include "media/audio/win/audio_manager_win.h"
+#include "media/audio/win/audio_session_event_listener_win.h"
 #include "media/audio/win/avrt_wrapper_win.h"
 #include "media/audio/win/core_audio_util_win.h"
 #include "media/base/audio_sample_types.h"
+#include "media/base/bind_to_current_loop.h"
 #include "media/base/limits.h"
 #include "media/base/media_switches.h"
 
@@ -32,7 +36,8 @@ using base::win::ScopedCoMem;
 namespace media {
 
 // static
-AUDCLNT_SHAREMODE WASAPIAudioOutputStream::GetShareMode() {
+AUDCLNT_SHAREMODE
+WASAPIAudioOutputStream::GetShareMode() {
   const base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
   if (cmd_line->HasSwitch(switches::kEnableExclusiveAudio))
     return AUDCLNT_SHAREMODE_EXCLUSIVE;
@@ -245,6 +250,11 @@ bool WASAPIAudioOutputStream::Open() {
     return false;
   }
 
+  session_listener_ = std::make_unique<AudioSessionEventListener>(
+      audio_client_.Get(), BindToCurrentLoop(base::BindOnce(
+                               &WASAPIAudioOutputStream::OnDeviceChanged,
+                               weak_factory_.GetWeakPtr())));
+
   opened_ = true;
   return true;
 }
@@ -260,6 +270,14 @@ void WASAPIAudioOutputStream::Start(AudioSourceCallback* callback) {
     return;
   }
 
+  // Since a device change may occur between Open() and Start() we need to
+  // signal the change once we have a |callback|. It's okay if this ends up
+  // being delivered multiple times.
+  if (device_changed_) {
+    callback->OnError(AudioSourceCallback::ErrorType::kDeviceChange);
+    return;
+  }
+
   // Ensure that the endpoint buffer is prepared with silence. Also serves as
   // a sanity check for the IAudioClient and IAudioRenderClient which may have
   // been invalidated by Windows since the last Stop() call.
@@ -355,6 +373,8 @@ void WASAPIAudioOutputStream::Close() {
   DVLOG(1) << "WASAPIAudioOutputStream::Close()";
   DCHECK_EQ(GetCurrentThreadId(), creating_thread_id_);
 
+  session_listener_.reset();
+
   // It is valid to call Close() before calling open or Start().
   // It is also valid to call Close() after Start() has been called.
   Stop();
@@ -734,4 +754,10 @@ void WASAPIAudioOutputStream::ReportAndResetStats() {
   largest_glitch_ = base::TimeDelta();
 }
 
+void WASAPIAudioOutputStream::OnDeviceChanged() {
+  device_changed_ = true;
+  if (source_)
+    source_->OnError(AudioSourceCallback::ErrorType::kDeviceChange);
+}
+
 }  // namespace media

media/audio/win/audio_low_latency_output_win.h

@@ -104,6 +104,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/simple_thread.h"
 #include "base/win/scoped_co_mem.h"
@@ -116,6 +117,7 @@
 namespace media {
 
 class AudioManagerWin;
+class AudioSessionEventListener;
 
 // AudioOutputStream implementation using Windows Core Audio APIs.
 class MEDIA_EXPORT WASAPIAudioOutputStream :
@@ -174,6 +176,9 @@ class MEDIA_EXPORT WASAPIAudioOutputStream :
   // Reports audio stream glitch stats and resets them to their initial values.
   void ReportAndResetStats();
 
+  // Called by AudioSessionEventListener() when a device change occurs.
+  void OnDeviceChanged();
+
   // Contains the thread ID of the creating thread.
   const base::PlatformThreadId creating_thread_id_;
 
@@ -262,6 +267,14 @@ class MEDIA_EXPORT WASAPIAudioOutputStream :
 
   Microsoft::WRL::ComPtr<IAudioClock> audio_clock_;
 
+  bool device_changed_ = false;
+  std::unique_ptr<AudioSessionEventListener> session_listener_;
+
+  // Since AudioSessionEventListener needs to posts tasks back to the audio
+  // thread, it's possible to end up in a state where that task would execute
+  // after destruction of this class -- so use a WeakPtr to cancel safely.
+  base::WeakPtrFactory<WASAPIAudioOutputStream> weak_factory_{this};
+
   DISALLOW_COPY_AND_ASSIGN(WASAPIAudioOutputStream);
 };
 

media/audio/win/audio_manager_win.cc

@@ -56,15 +56,15 @@ DEFINE_GUID(AM_KSCATEGORY_AUDIO,
 namespace media {
 
 // Maximum number of output streams that can be open simultaneously.
-static const int kMaxOutputStreams = 50;
+constexpr int kMaxOutputStreams = 50;
 
 // Up to 8 channels can be passed to the driver.  This should work, given the
 // right drivers, but graceful error handling is needed.
-static const int kWinMaxChannels = 8;
+constexpr int kWinMaxChannels = 8;
 
 // Buffer size to use for input and output stream when a proper size can't be
 // determined from the system
-static const int kFallbackBufferSize = 2048;
+constexpr int kFallbackBufferSize = 2048;
 
 static int NumberOfWaveOutBuffers() {
   // Use the user provided buffer count if provided.
@@ -131,9 +131,10 @@ void AudioManagerWin::InitializeOnAudioThread() {
   DCHECK(GetTaskRunner()->BelongsToCurrentThread());
 
   // AudioDeviceListenerWin must be initialized on a COM thread.
-  output_device_listener_.reset(new AudioDeviceListenerWin(BindToCurrentLoop(
-      base::Bind(&AudioManagerWin::NotifyAllOutputDeviceChangeListeners,
-                 base::Unretained(this)))));
+  output_device_listener_ = std::make_unique<AudioDeviceListenerWin>(
+      BindToCurrentLoop(base::BindRepeating(
+          &AudioManagerWin::NotifyAllOutputDeviceChangeListeners,
+          base::Unretained(this))));
 }
 
 void AudioManagerWin::GetAudioDeviceNamesImpl(bool input,
@@ -205,7 +206,7 @@ AudioOutputStream* AudioManagerWin::MakeLinearOutputStream(
     const LogCallback& log_callback) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
   if (params.channels() > kWinMaxChannels)
-    return NULL;
+    return nullptr;
 
   return new PCMWaveOutAudioOutputStream(this, params, NumberOfWaveOutBuffers(),
                                          WAVE_MAPPER);
@@ -222,7 +223,13 @@ AudioOutputStream* AudioManagerWin::MakeLowLatencyOutputStream(
     const LogCallback& log_callback) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
   if (params.channels() > kWinMaxChannels)
-    return NULL;
+    return nullptr;
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kForceWaveAudio)) {
+    DLOG(WARNING) << "Forcing usage of Windows WaveXxx APIs";
+    return nullptr;
+  }
 
   // Pass an empty string to indicate that we want the default device
   // since we consistently only check for an empty string in

media/audio/win/audio_session_event_listener_win.cc

+// Copyright 2019 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 "media/audio/win/audio_session_event_listener_win.h"
+
+namespace media {
+
+AudioSessionEventListener::AudioSessionEventListener(
+    IAudioClient* client,
+    base::OnceClosure device_change_cb)
+    : device_change_cb_(std::move(device_change_cb)) {
+  DCHECK(device_change_cb_);
+
+  HRESULT hr = client->GetService(IID_PPV_ARGS(&audio_session_control_));
+  if (FAILED(hr)) {
+    DLOG(ERROR) << "Failed to get IAudioSessionControl service.";
+    return;
+  }
+
+  audio_session_control_->RegisterAudioSessionNotification(this);
+}
+
+AudioSessionEventListener::~AudioSessionEventListener() {
+  if (!audio_session_control_)
+    return;
+
+  HRESULT hr = audio_session_control_->UnregisterAudioSessionNotification(this);
+  DLOG_IF(ERROR, FAILED(hr))
+      << "UnregisterAudioSessionNotification() failed: " << std::hex << hr;
+}
+
+STDMETHODIMP_(ULONG) AudioSessionEventListener::AddRef() {
+  return 1;  // Class is owned in Chromium code and should have no outside refs.
+}
+
+STDMETHODIMP_(ULONG) AudioSessionEventListener::Release() {
+  return 1;  // Class is owned in Chromium code and should have no outside refs.
+}
+
+STDMETHODIMP AudioSessionEventListener::QueryInterface(REFIID iid,
+                                                       void** object) {
+  if (iid == IID_IUnknown || iid == __uuidof(IAudioSessionEvents)) {
+    *object = static_cast<IAudioSessionEvents*>(this);
+    return S_OK;
+  }
+
+  *object = nullptr;
+  return E_NOINTERFACE;
+}
+
+STDMETHODIMP AudioSessionEventListener::OnChannelVolumeChanged(
+    DWORD channel_count,
+    float new_channel_volume_array[],
+    DWORD changed_channel,
+    LPCGUID event_context) {
+  return S_OK;
+}
+
+STDMETHODIMP
+AudioSessionEventListener::OnDisplayNameChanged(LPCWSTR new_display_name,
+                                                LPCGUID event_context) {
+  return S_OK;
+}
+
+STDMETHODIMP AudioSessionEventListener::OnGroupingParamChanged(
+    LPCGUID new_grouping_param,
+    LPCGUID event_context) {
+  return S_OK;
+}
+
+STDMETHODIMP AudioSessionEventListener::OnIconPathChanged(
+    LPCWSTR new_icon_path,
+    LPCGUID event_context) {
+  return S_OK;
+}
+
+STDMETHODIMP AudioSessionEventListener::OnSessionDisconnected(
+    AudioSessionDisconnectReason disconnect_reason) {
+  DVLOG(1) << __func__ << ": " << disconnect_reason;
+  if (device_change_cb_)
+    std::move(device_change_cb_).Run();
+  return S_OK;
+}
+
+STDMETHODIMP AudioSessionEventListener::OnSimpleVolumeChanged(
+    float new_volume,
+    BOOL new_mute,
+    LPCGUID event_context) {
+  return S_OK;
+}
+
+STDMETHODIMP AudioSessionEventListener::OnStateChanged(
+    AudioSessionState new_state) {
+  return S_OK;
+}
+
+}  // namespace media

media/audio/win/audio_session_event_listener_win.h

+// Copyright 2019 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.
+
+#ifndef MEDIA_AUDIO_WIN_AUDIO_SESSION_EVENT_LISTENER_WIN_H_
+#define MEDIA_AUDIO_WIN_AUDIO_SESSION_EVENT_LISTENER_WIN_H_
+
+#include <audiopolicy.h>
+#include <wrl/client.h>
+
+#include "base/callback.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class MEDIA_EXPORT AudioSessionEventListener : public IAudioSessionEvents {
+ public:
+  // Calls RegisterAudioSessionNotification() on |client| and calls
+  // |device_change_cb| when OnSessionDisconnected() is called.
+  //
+  // Since the IAudioClient session is dead after the disconnection, we use a
+  // OnceCallback. The delivery of this notification is fatal to the |client|.
+  AudioSessionEventListener(IAudioClient* client,
+                            base::OnceClosure device_change_cb);
+  virtual ~AudioSessionEventListener();
+
+ private:
+  friend class AudioSessionEventListenerTest;
+
+  STDMETHOD_(ULONG, AddRef)() override;
+  STDMETHOD_(ULONG, Release)() override;
+  STDMETHOD(QueryInterface)(REFIID iid, void** object) override;
+
+  // IAudioSessionEvents implementation.
+  STDMETHOD(OnChannelVolumeChanged)
+  (DWORD channel_count,
+   float new_channel_volume_array[],
+   DWORD changed_channel,
+   LPCGUID event_context) override;
+  STDMETHOD(OnDisplayNameChanged)
+  (LPCWSTR new_display_name, LPCGUID event_context) override;
+  STDMETHOD(OnGroupingParamChanged)
+  (LPCGUID new_grouping_param, LPCGUID event_context) override;
+  STDMETHOD(OnIconPathChanged)
+  (LPCWSTR new_icon_path, LPCGUID event_context) override;
+  STDMETHOD(OnSessionDisconnected)
+  (AudioSessionDisconnectReason disconnect_reason) override;
+  STDMETHOD(OnSimpleVolumeChanged)
+  (float new_volume, BOOL new_mute, LPCGUID event_context) override;
+  STDMETHOD(OnStateChanged)(AudioSessionState new_state) override;
+
+  base::OnceClosure device_change_cb_;
+  Microsoft::WRL::ComPtr<IAudioSessionControl> audio_session_control_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_AUDIO_WIN_AUDIO_SESSION_EVENT_LISTENER_WIN_H_

media/audio/win/audio_session_event_listener_win_unittest.cc

+// Copyright 2019 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 "media/audio/win/audio_session_event_listener_win.h"
+
+#include <memory>
+
+#include "base/bind_helpers.h"
+#include "base/win/scoped_com_initializer.h"
+#include "media/audio/audio_unittest_util.h"
+#include "media/audio/win/core_audio_util_win.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+static bool DevicesAvailable() {
+  return media::CoreAudioUtil::IsSupported() &&
+         media::CoreAudioUtil::NumberOfActiveDevices(eRender) > 0;
+}
+
+}  // namespace
+
+namespace media {
+
+class AudioSessionEventListenerTest : public testing::Test {
+ public:
+  AudioSessionEventListenerTest() {
+    if (!DevicesAvailable())
+      return;
+
+    audio_client_ =
+        CoreAudioUtil::CreateClient(std::string(), eRender, eConsole);
+    CHECK(audio_client_);
+
+    // AudioClient must be initialized to succeed in getting the session.
+    WAVEFORMATEXTENSIBLE format;
+    EXPECT_TRUE(SUCCEEDED(
+        CoreAudioUtil::GetSharedModeMixFormat(audio_client_.Get(), &format)));
+
+    // Perform a shared-mode initialization without event-driven buffer
+    // handling.
+    uint32_t endpoint_buffer_size = 0;
+    HRESULT hr = CoreAudioUtil::SharedModeInitialize(
+        audio_client_.Get(), &format, nullptr, 0, &endpoint_buffer_size,
+        nullptr);
+    EXPECT_TRUE(SUCCEEDED(hr));
+
+    listener_ = std::make_unique<AudioSessionEventListener>(
+        audio_client_.Get(),
+        base::BindOnce(&AudioSessionEventListenerTest::OnSessionDisconnected,
+                       base::Unretained(this)));
+  }
+
+  ~AudioSessionEventListenerTest() override = default;
+
+  void SimulateSessionDisconnected() {
+    listener_->OnSessionDisconnected(DisconnectReasonDeviceRemoval);
+  }
+
+  MOCK_METHOD0(OnSessionDisconnected, void());
+
+ protected:
+  base::win::ScopedCOMInitializer com_init_;
+  Microsoft::WRL::ComPtr<IAudioClient> audio_client_;
+  std::unique_ptr<AudioSessionEventListener> listener_;
+};
+
+TEST_F(AudioSessionEventListenerTest, Works) {
+  ABORT_AUDIO_TEST_IF_NOT(DevicesAvailable());
+
+  EXPECT_CALL(*this, OnSessionDisconnected());
+  SimulateSessionDisconnected();
+
+  // Calling it again shouldn't crash, but also shouldn't make any more calls.
+  EXPECT_CALL(*this, OnSessionDisconnected()).Times(0);
+  SimulateSessionDisconnected();
+}
+
+}  // namespace media

services/audio/output_controller.cc

@@ -436,9 +436,13 @@ void OutputController::LogAudioPowerLevel(const char* call_name) {
 }
 
 void OutputController::OnError(ErrorType type) {
-  // TODO(dalecurtis): Handle type == ErrorType::kDeviceChange errors without
-  // delay.
-  //
+  if (type == ErrorType::kDeviceChange) {
+    task_runner_->PostTask(FROM_HERE,
+                           base::BindOnce(&OutputController::OnDeviceChange,
+                                          weak_this_for_stream_));
+    return;
+  }
+
   // Handle error on the audio controller thread.  We defer errors for one
   // second in case they are the result of a device change; delay chosen to
   // exceed duration of device changes which take a few hundred milliseconds.