Caching AudioOutputDevice instances in mixer manager

content/renderer/media/audio_renderer_mixer_manager_unittest.cc

 // Copyright (c) 2012 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/renderer/media/audio_renderer_mixer_manager.h"
 
 #include <memory>
 
+#include "base/bind.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "content/renderer/media/audio_device_factory.h"
+#include "content/renderer/media/audio_renderer_sink_cache.h"
 #include "media/audio/audio_device_description.h"
-#include "media/base/audio_capturer_source.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/audio_renderer_mixer.h"
 #include "media/base/audio_renderer_mixer_input.h"
 #include "media/base/fake_audio_render_callback.h"
 #include "media/base/mock_audio_renderer_sink.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace content {
 
+namespace {
 static const int kBitsPerChannel = 16;
 static const int kSampleRate = 48000;

[Guido Urdaneta, 2016/05/25 13:33:13]

static is redundant in all these constants. namespace/global constants are
static in C++ by default.

[o1ka, 2016/05/25 14:52:11]

Done.

 static const int kBufferSize = 8192;
 static const media::ChannelLayout kChannelLayout = media::CHANNEL_LAYOUT_STEREO;
 static const media::ChannelLayout kAnotherChannelLayout =
     media::CHANNEL_LAYOUT_2_1;
 static const char* const kDefaultDeviceId =
     media::AudioDeviceDescription::kDefaultDeviceId;
 static const char kAnotherDeviceId[] = "another-device-id";
 static const char kMatchedDeviceId[] = "matched-device-id";
 static const char kNonexistentDeviceId[] = "nonexistent-device-id";
 
 static const int kRenderFrameId = 124;
 static const int kAnotherRenderFrameId = 678;
+}  // namespace;
 
 using media::AudioParameters;
 
-class AudioRendererMixerManagerTest : public testing::Test,
-                                      public AudioDeviceFactory {
+class FakeAudioRendererSinkCache : public AudioRendererSinkCache {
+ public:
+  using GetSinkCallback =
+      base::Callback<scoped_refptr<media::AudioRendererSink>(
+          int render_frame_id,
+          int session_id,
+          const std::string& device_id,
+          const url::Origin& security_origin)>;
+
+  using ReleaseSinkCallback =
+      base::Callback<void(const media::AudioRendererSink*)>;
+
+  FakeAudioRendererSinkCache(const GetSinkCallback& get_sink_cb,
+                             const ReleaseSinkCallback& release_sink_cb)
+      : get_sink_cb_(get_sink_cb), release_sink_cb_(release_sink_cb) {}
+
+  media::OutputDeviceInfo GetSinkInfo(
+      int source_render_frame_id,
+      int session_id,
+      const std::string& device_id,
+      const url::Origin& security_origin) final {
+    return get_sink_cb_
+        .Run(source_render_frame_id, session_id, device_id, security_origin)
+        ->GetOutputDeviceInfo();
+  }
+
+  scoped_refptr<media::AudioRendererSink> GetSink(
+      int source_render_frame_id,
+      const std::string& device_id,
+      const url::Origin& security_origin) final {
+    return get_sink_cb_.Run(source_render_frame_id, 0, device_id,
+                            security_origin);
+  }
+
+  void ReleaseSink(const media::AudioRendererSink* sink) final {
+    release_sink_cb_.Run(sink);
+  }
+
+ private:
+  GetSinkCallback get_sink_cb_;
+  ReleaseSinkCallback release_sink_cb_;
+};
+
+class AudioRendererMixerManagerTest : public testing::Test {
  public:
   AudioRendererMixerManagerTest()
-      : manager_(new AudioRendererMixerManager()),
+      : manager_(new AudioRendererMixerManager(
+            std::unique_ptr<AudioRendererSinkCache>(
+                new FakeAudioRendererSinkCache(
+                    base::Bind(&AudioRendererMixerManagerTest::GetSinkPtr,
+                               base::Unretained(this)),
+                    base::Bind(&AudioRendererMixerManagerTest::ReleaseSinkPtr,
+                               base::Unretained(this)))))),
         mock_sink_(new media::MockAudioRendererSink()),
         mock_sink_no_device_(new media::MockAudioRendererSink(
             kNonexistentDeviceId,
             media::OUTPUT_DEVICE_STATUS_ERROR_NOT_FOUND)),
         mock_sink_matched_device_(
             new media::MockAudioRendererSink(kMatchedDeviceId,
                                              media::OUTPUT_DEVICE_STATUS_OK)),
-        mock_sink_for_session_id_(
-            new media::MockAudioRendererSink(kMatchedDeviceId,
-                                             media::OUTPUT_DEVICE_STATUS_OK)),
         kSecurityOrigin2(GURL("http://localhost")) {}
 
   media::AudioRendererMixer* GetMixer(
       int source_render_frame_id,
       const media::AudioParameters& params,
       const std::string& device_id,
       const url::Origin& security_origin,
       media::OutputDeviceStatus* device_status) {
     return manager_->GetMixer(source_render_frame_id, params, device_id,
                               security_origin, device_status);
   }
 
-  void RemoveMixer(int source_render_frame_id,
+  void ReturnMixer(int source_render_frame_id,
                    const media::AudioParameters& params,
                    const std::string& device_id,
                    const url::Origin& security_origin) {
-    return manager_->RemoveMixer(source_render_frame_id, params, device_id,
+    return manager_->ReturnMixer(source_render_frame_id, params, device_id,
                                  security_origin);
   }
 
   // Number of instantiated mixers.
   int mixer_count() {
     return manager_->mixers_.size();
   }
 
  protected:
-  MOCK_METHOD1(CreateAudioCapturerSource,
-               scoped_refptr<media::AudioCapturerSource>(int));
-  MOCK_METHOD5(
-      CreateSwitchableAudioRendererSink,
-      scoped_refptr<media::SwitchableAudioRendererSink>(SourceType,
-                                                        int,
-                                                        int,
-                                                        const std::string&,
-                                                        const url::Origin&));
-  MOCK_METHOD5(CreateAudioRendererSink,
-               scoped_refptr<media::AudioRendererSink>(SourceType,
-                                                       int,
-                                                       int,
-                                                       const std::string&,
-                                                       const url::Origin&));
-
-  scoped_refptr<media::AudioRendererSink> CreateFinalAudioRendererSink(
-      int render_frame_id,
+  scoped_refptr<media::AudioRendererSink> GetSinkPtr(
+      int source_render_frame_id,
       int session_id,
       const std::string& device_id,
       const url::Origin& security_origin) {
     if ((device_id == kDefaultDeviceId) || (device_id == kAnotherDeviceId)) {
       // We don't care about separate sinks for these devices.
       return mock_sink_;
     }
     if (device_id == kNonexistentDeviceId)
       return mock_sink_no_device_;
     if (device_id.empty()) {
       // The sink used to get device ID from session ID if it's not empty
-      return session_id ? mock_sink_for_session_id_ : mock_sink_;
+      return session_id ? mock_sink_matched_device_ : mock_sink_;
     }
     if (device_id == kMatchedDeviceId)
       return mock_sink_matched_device_;
 
     NOTREACHED();
     return nullptr;
   }
 
+  MOCK_METHOD1(ReleaseSinkPtr, void(const media::AudioRendererSink*));
+
   std::unique_ptr<AudioRendererMixerManager> manager_;
+
   scoped_refptr<media::MockAudioRendererSink> mock_sink_;
   scoped_refptr<media::MockAudioRendererSink> mock_sink_no_device_;
   scoped_refptr<media::MockAudioRendererSink> mock_sink_matched_device_;
-  scoped_refptr<media::MockAudioRendererSink> mock_sink_for_session_id_;
 
   // To avoid global/static non-POD constants.
   const url::Origin kSecurityOrigin;
   const url::Origin kSecurityOrigin2;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioRendererMixerManagerTest);
 };
 
-// Verify GetMixer() and RemoveMixer() both work as expected; particularly with
+// Verify GetMixer() and ReturnMixer() both work as expected; particularly with
 // respect to the explicit ref counting done.
-TEST_F(AudioRendererMixerManagerTest, GetRemoveMixer) {
+TEST_F(AudioRendererMixerManagerTest, GetReturnMixer) {
   // Since we're testing two different sets of parameters, we expect
   // AudioRendererMixerManager to call Start and Stop on our mock twice.
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(2);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(2);
 
+  // We expect 2 mixers to be created; each of them should release the sink.
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_.get())).Times(2);
+
   // There should be no mixers outstanding to start with.
   EXPECT_EQ(0, mixer_count());
 
   media::AudioParameters params1(
       AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate,
       kBitsPerChannel, kBufferSize);
 
   media::AudioRendererMixer* mixer1 = GetMixer(
       kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer1);
   EXPECT_EQ(1, mixer_count());
 
   // The same parameters should return the same mixer1.
   EXPECT_EQ(mixer1, GetMixer(kRenderFrameId, params1, kDefaultDeviceId,
                              kSecurityOrigin, nullptr));
   EXPECT_EQ(1, mixer_count());
 
-  // Remove the extra mixer we just acquired.
-  RemoveMixer(kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin);
+  // Return the extra mixer we just acquired.
+  ReturnMixer(kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
 
   media::AudioParameters params2(
       AudioParameters::AUDIO_PCM_LINEAR, kAnotherChannelLayout, kSampleRate * 2,
       kBitsPerChannel, kBufferSize * 2);
   media::AudioRendererMixer* mixer2 = GetMixer(
       kRenderFrameId, params2, kDefaultDeviceId, kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer2);
   EXPECT_EQ(2, mixer_count());
 
   // Different parameters should result in a different mixer1.
   EXPECT_NE(mixer1, mixer2);
 
-  // Remove both outstanding mixers.
-  RemoveMixer(kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin);
+  // Return both outstanding mixers.
+  ReturnMixer(kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
-  RemoveMixer(kRenderFrameId, params2, kDefaultDeviceId, kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params2, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(0, mixer_count());
 }
 
 // Verify GetMixer() correctly deduplicates mixer with irrelevant AudioParameter
 // differences.
 TEST_F(AudioRendererMixerManagerTest, MixerReuse) {
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(2);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(2);
   EXPECT_EQ(mixer_count(), 0);
 
+  // We expect 2 mixers to be created; each of them should release the sink.
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_.get())).Times(2);
+
   media::AudioParameters params1(AudioParameters::AUDIO_PCM_LINEAR,
                                  kChannelLayout,
                                  kSampleRate,
                                  kBitsPerChannel,
                                  kBufferSize);
   media::AudioRendererMixer* mixer1 = GetMixer(
       kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer1);
   EXPECT_EQ(1, mixer_count());
 
   // Different sample rates, formats, bit depths, and buffer sizes should not
   // result in a different mixer.
   media::AudioParameters params2(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                                  kChannelLayout,
                                  kSampleRate * 2,
                                  kBitsPerChannel * 2,
                                  kBufferSize * 2);
   EXPECT_EQ(mixer1, GetMixer(kRenderFrameId, params2, kDefaultDeviceId,
                              kSecurityOrigin, nullptr));
   EXPECT_EQ(1, mixer_count());
-  RemoveMixer(kRenderFrameId, params2, kDefaultDeviceId, kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params2, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
 
   // Modify some parameters that do matter: channel layout
   media::AudioParameters params3(AudioParameters::AUDIO_PCM_LOW_LATENCY,
                                  kAnotherChannelLayout,
                                  kSampleRate,
                                  kBitsPerChannel,
                                  kBufferSize);
   ASSERT_NE(params3.channel_layout(), params1.channel_layout());
 
   EXPECT_NE(mixer1, GetMixer(kRenderFrameId, params3, kDefaultDeviceId,
                              kSecurityOrigin, nullptr));
   EXPECT_EQ(2, mixer_count());
-  RemoveMixer(kRenderFrameId, params3, kDefaultDeviceId, kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params3, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
 
-  // Remove final mixer.
-  RemoveMixer(kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin);
+  // Return final mixer.
+  ReturnMixer(kRenderFrameId, params1, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(0, mixer_count());
 }
 
 // Verify CreateInput() provides AudioRendererMixerInput with the appropriate
 // callbacks and they are working as expected.  Also, verify that separate
 // mixers are created for separate render views, even though the AudioParameters
 // are the same.
 TEST_F(AudioRendererMixerManagerTest, CreateInput) {
   // Expect AudioRendererMixerManager to call Start and Stop on our mock twice
   // each.  Note: Under normal conditions, each mixer would get its own sink!
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(2);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(2);
 
+  // We expect 2 mixers to be created; each of them should release the sink.
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_.get())).Times(2);
+
   media::AudioParameters params(
       AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate,
       kBitsPerChannel, kBufferSize);
 
   // Create two mixer inputs and ensure this doesn't instantiate any mixers yet.
   EXPECT_EQ(0, mixer_count());
   media::FakeAudioRenderCallback callback(0);
   scoped_refptr<media::AudioRendererMixerInput> input(manager_->CreateInput(
       kRenderFrameId, 0, kDefaultDeviceId, kSecurityOrigin));
   input->Initialize(params, &callback);
   EXPECT_EQ(0, mixer_count());
   media::FakeAudioRenderCallback another_callback(1);
   scoped_refptr<media::AudioRendererMixerInput> another_input(
       manager_->CreateInput(kAnotherRenderFrameId, 0, kDefaultDeviceId,
                             kSecurityOrigin));
   another_input->Initialize(params, &another_callback);
   EXPECT_EQ(0, mixer_count());
 
   // Implicitly test that AudioRendererMixerInput was provided with the expected
-  // callbacks needed to acquire an AudioRendererMixer and remove it.
+  // callbacks needed to acquire an AudioRendererMixer and return it.
   input->Start();
   EXPECT_EQ(1, mixer_count());
   another_input->Start();
   EXPECT_EQ(2, mixer_count());
 
   // Destroying the inputs should destroy the mixers.
   input->Stop();
   input = nullptr;
   EXPECT_EQ(1, mixer_count());
   another_input->Stop();
   another_input = nullptr;
   EXPECT_EQ(0, mixer_count());
 }
 
 // Verify CreateInput() provided with session id creates AudioRendererMixerInput
 // with the appropriate callbacks and they are working as expected.
 TEST_F(AudioRendererMixerManagerTest, CreateInputWithSessionId) {
   // Expect AudioRendererMixerManager to call Start and Stop on our mock twice
   // each: for kDefaultDeviceId and for kAnotherDeviceId. Note: Under normal
   // conditions, each mixer would get its own sink!
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(2);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(2);
 
   // Expect AudioRendererMixerManager to call Start and Stop on the matched sink
   // once.
   EXPECT_CALL(*mock_sink_matched_device_.get(), Start()).Times(1);
   EXPECT_CALL(*mock_sink_matched_device_.get(), Stop()).Times(1);
 
+  // We expect 3 mixers to be created; each of them should release a sink.
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_.get())).Times(2);
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_matched_device_.get())).Times(1);
+
   media::AudioParameters params(AudioParameters::AUDIO_PCM_LINEAR,
                                 kChannelLayout, kSampleRate, kBitsPerChannel,
                                 kBufferSize);
   media::FakeAudioRenderCallback callback(0);
   EXPECT_EQ(0, mixer_count());
 
   // Empty device id, zero session id;
   scoped_refptr<media::AudioRendererMixerInput> input_to_default_device(
       manager_->CreateInput(kRenderFrameId, 0,  // session_id
                             std::string(), kSecurityOrigin));
@@ skipping 16 matching lines @@
 
   // Empty device id, non-zero session id;
   scoped_refptr<media::AudioRendererMixerInput>
       input_to_matched_device_with_session_id(
           manager_->CreateInput(kRenderFrameId, 2,  // session id
                                 std::string(), kSecurityOrigin));
   input_to_matched_device_with_session_id->Initialize(params, &callback);
   EXPECT_EQ(0, mixer_count());
 
   // Implicitly test that AudioRendererMixerInput was provided with the expected
-  // callbacks needed to acquire an AudioRendererMixer and remove it.
+  // callbacks needed to acquire an AudioRendererMixer and return it.
   input_to_default_device->Start();
   EXPECT_EQ(1, mixer_count());
 
   input_to_another_device->Start();
   EXPECT_EQ(2, mixer_count());
 
   input_to_matched_device->Start();
   EXPECT_EQ(3, mixer_count());
 
   // Should go to the same device as the input above.
@@ skipping 15 matching lines @@
   EXPECT_EQ(0, mixer_count());
 }
 
 // Verify GetMixer() correctly creates different mixers with the same
 // parameters, but different device ID and/or security origin
 TEST_F(AudioRendererMixerManagerTest, MixerDevices) {
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(3);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(3);
   EXPECT_EQ(0, mixer_count());
 
+  // We expect 3 mixers to be created; each of them should release a sink.
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_.get())).Times(3);
+
   media::AudioParameters params(AudioParameters::AUDIO_PCM_LINEAR,
                                 kChannelLayout, kSampleRate, kBitsPerChannel,
                                 kBufferSize);
   media::AudioRendererMixer* mixer1 = GetMixer(
       kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer1);
   EXPECT_EQ(1, mixer_count());
 
   media::AudioRendererMixer* mixer2 = GetMixer(
       kRenderFrameId, params, kAnotherDeviceId, kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer2);
   EXPECT_EQ(2, mixer_count());
   EXPECT_NE(mixer1, mixer2);
 
   media::AudioRendererMixer* mixer3 = GetMixer(
       kRenderFrameId, params, kAnotherDeviceId, kSecurityOrigin2, nullptr);
   ASSERT_TRUE(mixer3);
   EXPECT_EQ(3, mixer_count());
   EXPECT_NE(mixer1, mixer3);
   EXPECT_NE(mixer2, mixer3);
 
-  RemoveMixer(kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(2, mixer_count());
-  RemoveMixer(kRenderFrameId, params, kAnotherDeviceId, kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params, kAnotherDeviceId, kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
-  RemoveMixer(kRenderFrameId, params, kAnotherDeviceId, kSecurityOrigin2);
+  ReturnMixer(kRenderFrameId, params, kAnotherDeviceId, kSecurityOrigin2);
   EXPECT_EQ(0, mixer_count());
 }
 
 // Verify GetMixer() correctly deduplicate mixers with the same
 // parameters, different security origins but default device ID
 TEST_F(AudioRendererMixerManagerTest, OneMixerDifferentOriginsDefaultDevice) {
   EXPECT_CALL(*mock_sink_.get(), Start()).Times(1);
   EXPECT_CALL(*mock_sink_.get(), Stop()).Times(1);
   EXPECT_EQ(0, mixer_count());
 
+  // We expect 1 mixers to be created; it should release its sink.

[Guido Urdaneta, 2016/05/25 13:33:13]

nit: s/mixers/mixer

[o1ka, 2016/05/25 14:52:11]

Done.

+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_.get())).Times(1);
+
   media::AudioParameters params(AudioParameters::AUDIO_PCM_LINEAR,
                                 kChannelLayout, kSampleRate, kBitsPerChannel,
                                 kBufferSize);
   media::AudioRendererMixer* mixer1 = GetMixer(
       kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer1);
   EXPECT_EQ(1, mixer_count());
 
   media::AudioRendererMixer* mixer2 =
       GetMixer(kRenderFrameId, params, std::string(), kSecurityOrigin, nullptr);
   ASSERT_TRUE(mixer2);
   EXPECT_EQ(1, mixer_count());
   EXPECT_EQ(mixer1, mixer2);
 
   media::AudioRendererMixer* mixer3 = GetMixer(
       kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin2, nullptr);
   ASSERT_TRUE(mixer3);
   EXPECT_EQ(1, mixer_count());
   EXPECT_EQ(mixer1, mixer3);
 
   media::AudioRendererMixer* mixer4 = GetMixer(
       kRenderFrameId, params, std::string(), kSecurityOrigin2, nullptr);
   ASSERT_TRUE(mixer4);
   EXPECT_EQ(1, mixer_count());
   EXPECT_EQ(mixer1, mixer4);
 
-  RemoveMixer(kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
-  RemoveMixer(kRenderFrameId, params, std::string(), kSecurityOrigin);
+  ReturnMixer(kRenderFrameId, params, std::string(), kSecurityOrigin);
   EXPECT_EQ(1, mixer_count());
-  RemoveMixer(kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin2);
+  ReturnMixer(kRenderFrameId, params, kDefaultDeviceId, kSecurityOrigin2);
   EXPECT_EQ(1, mixer_count());
-  RemoveMixer(kRenderFrameId, params, std::string(), kSecurityOrigin2);
+  ReturnMixer(kRenderFrameId, params, std::string(), kSecurityOrigin2);
   EXPECT_EQ(0, mixer_count());
 }
 
 // Verify that GetMixer() correctly returns a null mixer and an appropriate
 // status code when a nonexistent device is requested.
 TEST_F(AudioRendererMixerManagerTest, NonexistentDevice) {
   EXPECT_EQ(0, mixer_count());
+
+  // Mixer manager should release a not-ok sink when failing to create a mixer.
+  EXPECT_CALL(*this, ReleaseSinkPtr(mock_sink_no_device_.get())).Times(1);
+
   media::AudioParameters params(AudioParameters::AUDIO_PCM_LINEAR,
                                 kChannelLayout, kSampleRate, kBitsPerChannel,
                                 kBufferSize);
   media::OutputDeviceStatus device_status = media::OUTPUT_DEVICE_STATUS_OK;
-  EXPECT_CALL(*mock_sink_no_device_.get(), Stop());
+
   media::AudioRendererMixer* mixer =
       GetMixer(kRenderFrameId, params, kNonexistentDeviceId, kSecurityOrigin,
                &device_status);
+
   EXPECT_FALSE(mixer);
   EXPECT_EQ(media::OUTPUT_DEVICE_STATUS_ERROR_NOT_FOUND, device_status);
   EXPECT_EQ(0, mixer_count());
 }
 
 }  // namespace content