Re-subimission of https://codereview.chromium.org/1041213003/
[chromium-blink-merge.git] / content / renderer / media / webrtc_local_audio_track_unittest.cc
blobb27c222a981c25e0db11e944475595ad55741bea
1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "base/synchronization/waitable_event.h"
6 #include "base/test/test_timeouts.h"
7 #include "content/public/renderer/media_stream_audio_sink.h"
8 #include "content/renderer/media/media_stream_audio_source.h"
9 #include "content/renderer/media/mock_media_constraint_factory.h"
10 #include "content/renderer/media/webrtc/webrtc_local_audio_track_adapter.h"
11 #include "content/renderer/media/webrtc_audio_capturer.h"
12 #include "content/renderer/media/webrtc_local_audio_track.h"
13 #include "media/audio/audio_parameters.h"
14 #include "media/base/audio_bus.h"
15 #include "media/base/audio_capturer_source.h"
16 #include "testing/gmock/include/gmock/gmock.h"
17 #include "testing/gtest/include/gtest/gtest.h"
18 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
19 #include "third_party/WebKit/public/web/WebHeap.h"
20 #include "third_party/libjingle/source/talk/app/webrtc/mediastreaminterface.h"
22 using ::testing::_;
23 using ::testing::AnyNumber;
24 using ::testing::AtLeast;
25 using ::testing::Return;
27 namespace content {
29 namespace {
31 ACTION_P(SignalEvent, event) {
32 event->Signal();
35 // A simple thread that we use to fake the audio thread which provides data to
36 // the |WebRtcAudioCapturer|.
37 class FakeAudioThread : public base::PlatformThread::Delegate {
38 public:
39 FakeAudioThread(WebRtcAudioCapturer* capturer,
40 const media::AudioParameters& params)
41 : capturer_(capturer),
42 thread_(),
43 closure_(false, false) {
44 DCHECK(capturer);
45 audio_bus_ = media::AudioBus::Create(params);
48 ~FakeAudioThread() override { DCHECK(thread_.is_null()); }
50 // base::PlatformThread::Delegate:
51 void ThreadMain() override {
52 while (true) {
53 if (closure_.IsSignaled())
54 return;
56 media::AudioCapturerSource::CaptureCallback* callback =
57 static_cast<media::AudioCapturerSource::CaptureCallback*>(
58 capturer_);
59 audio_bus_->Zero();
60 callback->Capture(audio_bus_.get(), 0, 0, false);
62 // Sleep 1ms to yield the resource for the main thread.
63 base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(1));
67 void Start() {
68 base::PlatformThread::CreateWithPriority(
69 0, this, &thread_, base::ThreadPriority::REALTIME_AUDIO);
70 CHECK(!thread_.is_null());
73 void Stop() {
74 closure_.Signal();
75 base::PlatformThread::Join(thread_);
76 thread_ = base::PlatformThreadHandle();
79 private:
80 scoped_ptr<media::AudioBus> audio_bus_;
81 WebRtcAudioCapturer* capturer_;
82 base::PlatformThreadHandle thread_;
83 base::WaitableEvent closure_;
84 DISALLOW_COPY_AND_ASSIGN(FakeAudioThread);
87 class MockCapturerSource : public media::AudioCapturerSource {
88 public:
89 explicit MockCapturerSource(WebRtcAudioCapturer* capturer)
90 : capturer_(capturer) {}
91 MOCK_METHOD3(OnInitialize, void(const media::AudioParameters& params,
92 CaptureCallback* callback,
93 int session_id));
94 MOCK_METHOD0(OnStart, void());
95 MOCK_METHOD0(OnStop, void());
96 MOCK_METHOD1(SetVolume, void(double volume));
97 MOCK_METHOD1(SetAutomaticGainControl, void(bool enable));
99 virtual void Initialize(const media::AudioParameters& params,
100 CaptureCallback* callback,
101 int session_id) override {
102 DCHECK(params.IsValid());
103 params_ = params;
104 OnInitialize(params, callback, session_id);
106 virtual void Start() override {
107 audio_thread_.reset(new FakeAudioThread(capturer_, params_));
108 audio_thread_->Start();
109 OnStart();
111 virtual void Stop() override {
112 audio_thread_->Stop();
113 audio_thread_.reset();
114 OnStop();
116 protected:
117 virtual ~MockCapturerSource() {}
119 private:
120 scoped_ptr<FakeAudioThread> audio_thread_;
121 WebRtcAudioCapturer* capturer_;
122 media::AudioParameters params_;
125 class MockMediaStreamAudioSink : public MediaStreamAudioSink {
126 public:
127 MockMediaStreamAudioSink() {}
128 ~MockMediaStreamAudioSink() {}
129 void OnData(const media::AudioBus& audio_bus,
130 base::TimeTicks estimated_capture_time) override {
131 EXPECT_EQ(params_.channels(), audio_bus.channels());
132 EXPECT_EQ(params_.frames_per_buffer(), audio_bus.frames());
133 EXPECT_FALSE(estimated_capture_time.is_null());
134 CaptureData();
136 MOCK_METHOD0(CaptureData, void());
137 void OnSetFormat(const media::AudioParameters& params) {
138 params_ = params;
139 FormatIsSet();
141 MOCK_METHOD0(FormatIsSet, void());
143 const media::AudioParameters& audio_params() const { return params_; }
145 private:
146 media::AudioParameters params_;
149 } // namespace
151 class WebRtcLocalAudioTrackTest : public ::testing::Test {
152 protected:
153 void SetUp() override {
154 params_.Reset(media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
155 media::CHANNEL_LAYOUT_STEREO, 2, 48000, 16, 480);
156 MockMediaConstraintFactory constraint_factory;
157 blink_source_.initialize("dummy", blink::WebMediaStreamSource::TypeAudio,
158 "dummy",
159 false /* remote */, true /* readonly */);
160 MediaStreamAudioSource* audio_source = new MediaStreamAudioSource();
161 blink_source_.setExtraData(audio_source);
163 StreamDeviceInfo device(MEDIA_DEVICE_AUDIO_CAPTURE,
164 std::string(), std::string());
165 capturer_ = WebRtcAudioCapturer::CreateCapturer(
166 -1, device, constraint_factory.CreateWebMediaConstraints(), NULL,
167 audio_source);
168 audio_source->SetAudioCapturer(capturer_.get());
169 capturer_source_ = new MockCapturerSource(capturer_.get());
170 EXPECT_CALL(*capturer_source_.get(), OnInitialize(_, capturer_.get(), -1))
171 .WillOnce(Return());
172 EXPECT_CALL(*capturer_source_.get(), SetAutomaticGainControl(true));
173 EXPECT_CALL(*capturer_source_.get(), OnStart());
174 capturer_->SetCapturerSource(capturer_source_, params_);
177 void TearDown() override {
178 blink_source_.reset();
179 blink::WebHeap::collectAllGarbageForTesting();
182 media::AudioParameters params_;
183 blink::WebMediaStreamSource blink_source_;
184 scoped_refptr<MockCapturerSource> capturer_source_;
185 scoped_refptr<WebRtcAudioCapturer> capturer_;
188 // Creates a capturer and audio track, fakes its audio thread, and
189 // connect/disconnect the sink to the audio track on the fly, the sink should
190 // get data callback when the track is connected to the capturer but not when
191 // the track is disconnected from the capturer.
192 TEST_F(WebRtcLocalAudioTrackTest, ConnectAndDisconnectOneSink) {
193 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter(
194 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
195 scoped_ptr<WebRtcLocalAudioTrack> track(
196 new WebRtcLocalAudioTrack(adapter.get(), capturer_, NULL));
197 track->Start();
198 EXPECT_TRUE(track->GetAudioAdapter()->enabled());
200 scoped_ptr<MockMediaStreamAudioSink> sink(new MockMediaStreamAudioSink());
201 base::WaitableEvent event(false, false);
202 EXPECT_CALL(*sink, FormatIsSet());
203 EXPECT_CALL(*sink,
204 CaptureData()).Times(AtLeast(1))
205 .WillRepeatedly(SignalEvent(&event));
206 track->AddSink(sink.get());
207 EXPECT_TRUE(event.TimedWait(TestTimeouts::tiny_timeout()));
208 track->RemoveSink(sink.get());
210 EXPECT_CALL(*capturer_source_.get(), OnStop()).WillOnce(Return());
211 capturer_->Stop();
214 // The same setup as ConnectAndDisconnectOneSink, but enable and disable the
215 // audio track on the fly. When the audio track is disabled, there is no data
216 // callback to the sink; when the audio track is enabled, there comes data
217 // callback.
218 // TODO(xians): Enable this test after resolving the racing issue that TSAN
219 // reports on MediaStreamTrack::enabled();
220 TEST_F(WebRtcLocalAudioTrackTest, DISABLED_DisableEnableAudioTrack) {
221 EXPECT_CALL(*capturer_source_.get(), SetAutomaticGainControl(true));
222 EXPECT_CALL(*capturer_source_.get(), OnStart());
223 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter(
224 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
225 scoped_ptr<WebRtcLocalAudioTrack> track(
226 new WebRtcLocalAudioTrack(adapter.get(), capturer_, NULL));
227 track->Start();
228 EXPECT_TRUE(track->GetAudioAdapter()->enabled());
229 EXPECT_TRUE(track->GetAudioAdapter()->set_enabled(false));
230 scoped_ptr<MockMediaStreamAudioSink> sink(new MockMediaStreamAudioSink());
231 const media::AudioParameters params = capturer_->source_audio_parameters();
232 base::WaitableEvent event(false, false);
233 EXPECT_CALL(*sink, FormatIsSet()).Times(1);
234 EXPECT_CALL(*sink, CaptureData()).Times(0);
235 EXPECT_EQ(sink->audio_params().frames_per_buffer(),
236 params.sample_rate() / 100);
237 track->AddSink(sink.get());
238 EXPECT_FALSE(event.TimedWait(TestTimeouts::tiny_timeout()));
240 event.Reset();
241 EXPECT_CALL(*sink, CaptureData()).Times(AtLeast(1))
242 .WillRepeatedly(SignalEvent(&event));
243 EXPECT_TRUE(track->GetAudioAdapter()->set_enabled(true));
244 EXPECT_TRUE(event.TimedWait(TestTimeouts::tiny_timeout()));
245 track->RemoveSink(sink.get());
247 EXPECT_CALL(*capturer_source_.get(), OnStop()).WillOnce(Return());
248 capturer_->Stop();
249 track.reset();
252 // Create multiple audio tracks and enable/disable them, verify that the audio
253 // callbacks appear/disappear.
254 // Flaky due to a data race, see http://crbug.com/295418
255 TEST_F(WebRtcLocalAudioTrackTest, DISABLED_MultipleAudioTracks) {
256 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter_1(
257 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
258 scoped_ptr<WebRtcLocalAudioTrack> track_1(
259 new WebRtcLocalAudioTrack(adapter_1.get(), capturer_, NULL));
260 track_1->Start();
261 EXPECT_TRUE(track_1->GetAudioAdapter()->enabled());
262 scoped_ptr<MockMediaStreamAudioSink> sink_1(new MockMediaStreamAudioSink());
263 const media::AudioParameters params = capturer_->source_audio_parameters();
264 base::WaitableEvent event_1(false, false);
265 EXPECT_CALL(*sink_1, FormatIsSet()).WillOnce(Return());
266 EXPECT_CALL(*sink_1, CaptureData()).Times(AtLeast(1))
267 .WillRepeatedly(SignalEvent(&event_1));
268 EXPECT_EQ(sink_1->audio_params().frames_per_buffer(),
269 params.sample_rate() / 100);
270 track_1->AddSink(sink_1.get());
271 EXPECT_TRUE(event_1.TimedWait(TestTimeouts::tiny_timeout()));
273 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter_2(
274 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
275 scoped_ptr<WebRtcLocalAudioTrack> track_2(
276 new WebRtcLocalAudioTrack(adapter_2.get(), capturer_, NULL));
277 track_2->Start();
278 EXPECT_TRUE(track_2->GetAudioAdapter()->enabled());
280 // Verify both |sink_1| and |sink_2| get data.
281 event_1.Reset();
282 base::WaitableEvent event_2(false, false);
284 scoped_ptr<MockMediaStreamAudioSink> sink_2(new MockMediaStreamAudioSink());
285 EXPECT_CALL(*sink_2, FormatIsSet()).WillOnce(Return());
286 EXPECT_CALL(*sink_1, CaptureData()).Times(AtLeast(1))
287 .WillRepeatedly(SignalEvent(&event_1));
288 EXPECT_EQ(sink_1->audio_params().frames_per_buffer(),
289 params.sample_rate() / 100);
290 EXPECT_CALL(*sink_2, CaptureData()).Times(AtLeast(1))
291 .WillRepeatedly(SignalEvent(&event_2));
292 EXPECT_EQ(sink_2->audio_params().frames_per_buffer(),
293 params.sample_rate() / 100);
294 track_2->AddSink(sink_2.get());
295 EXPECT_TRUE(event_1.TimedWait(TestTimeouts::tiny_timeout()));
296 EXPECT_TRUE(event_2.TimedWait(TestTimeouts::tiny_timeout()));
298 track_1->RemoveSink(sink_1.get());
299 track_1->Stop();
300 track_1.reset();
302 EXPECT_CALL(*capturer_source_.get(), OnStop()).WillOnce(Return());
303 track_2->RemoveSink(sink_2.get());
304 track_2->Stop();
305 track_2.reset();
309 // Start one track and verify the capturer is correctly starting its source.
310 // And it should be fine to not to call Stop() explicitly.
311 TEST_F(WebRtcLocalAudioTrackTest, StartOneAudioTrack) {
312 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter(
313 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
314 scoped_ptr<WebRtcLocalAudioTrack> track(
315 new WebRtcLocalAudioTrack(adapter.get(), capturer_, NULL));
316 track->Start();
318 // When the track goes away, it will automatically stop the
319 // |capturer_source_|.
320 EXPECT_CALL(*capturer_source_.get(), OnStop());
321 track.reset();
324 // Start two tracks and verify the capturer is correctly starting its source.
325 // When the last track connected to the capturer is stopped, the source is
326 // stopped.
327 TEST_F(WebRtcLocalAudioTrackTest, StartTwoAudioTracks) {
328 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter1(
329 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
330 scoped_ptr<WebRtcLocalAudioTrack> track1(
331 new WebRtcLocalAudioTrack(adapter1.get(), capturer_, NULL));
332 track1->Start();
334 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter2(
335 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
336 scoped_ptr<WebRtcLocalAudioTrack> track2(
337 new WebRtcLocalAudioTrack(adapter2.get(), capturer_, NULL));
338 track2->Start();
340 track1->Stop();
341 // When the last track is stopped, it will automatically stop the
342 // |capturer_source_|.
343 EXPECT_CALL(*capturer_source_.get(), OnStop());
344 track2->Stop();
347 // Start/Stop tracks and verify the capturer is correctly starting/stopping
348 // its source.
349 TEST_F(WebRtcLocalAudioTrackTest, StartAndStopAudioTracks) {
350 base::WaitableEvent event(false, false);
351 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter_1(
352 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
353 scoped_ptr<WebRtcLocalAudioTrack> track_1(
354 new WebRtcLocalAudioTrack(adapter_1.get(), capturer_, NULL));
355 track_1->Start();
357 // Verify the data flow by connecting the sink to |track_1|.
358 scoped_ptr<MockMediaStreamAudioSink> sink(new MockMediaStreamAudioSink());
359 event.Reset();
360 EXPECT_CALL(*sink, FormatIsSet()).WillOnce(SignalEvent(&event));
361 EXPECT_CALL(*sink, CaptureData())
362 .Times(AnyNumber()).WillRepeatedly(Return());
363 track_1->AddSink(sink.get());
364 EXPECT_TRUE(event.TimedWait(TestTimeouts::tiny_timeout()));
366 // Start the second audio track will not start the |capturer_source_|
367 // since it has been started.
368 EXPECT_CALL(*capturer_source_.get(), OnStart()).Times(0);
369 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter_2(
370 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
371 scoped_ptr<WebRtcLocalAudioTrack> track_2(
372 new WebRtcLocalAudioTrack(adapter_2.get(), capturer_, NULL));
373 track_2->Start();
375 // Stop the capturer will clear up the track lists in the capturer.
376 EXPECT_CALL(*capturer_source_.get(), OnStop());
377 capturer_->Stop();
379 // Adding a new track to the capturer.
380 track_2->AddSink(sink.get());
381 EXPECT_CALL(*sink, FormatIsSet()).Times(0);
383 // Stop the capturer again will not trigger stopping the source of the
384 // capturer again..
385 event.Reset();
386 EXPECT_CALL(*capturer_source_.get(), OnStop()).Times(0);
387 capturer_->Stop();
390 // Contains data races reported by tsan: crbug.com/404133
391 #if defined(THREAD_SANITIZER)
392 #define DISABLE_ON_TSAN(function) DISABLED_##function
393 #else
394 #define DISABLE_ON_TSAN(function) function
395 #endif
397 // Create a new capturer with new source, connect it to a new audio track.
398 TEST_F(WebRtcLocalAudioTrackTest,
399 DISABLE_ON_TSAN(ConnectTracksToDifferentCapturers)) {
400 // Setup the first audio track and start it.
401 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter_1(
402 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
403 scoped_ptr<WebRtcLocalAudioTrack> track_1(
404 new WebRtcLocalAudioTrack(adapter_1.get(), capturer_, NULL));
405 track_1->Start();
407 // Verify the data flow by connecting the |sink_1| to |track_1|.
408 scoped_ptr<MockMediaStreamAudioSink> sink_1(new MockMediaStreamAudioSink());
409 EXPECT_CALL(*sink_1.get(), CaptureData())
410 .Times(AnyNumber()).WillRepeatedly(Return());
411 EXPECT_CALL(*sink_1.get(), FormatIsSet()).Times(AnyNumber());
412 track_1->AddSink(sink_1.get());
414 // Create a new capturer with new source with different audio format.
415 MockMediaConstraintFactory constraint_factory;
416 StreamDeviceInfo device(MEDIA_DEVICE_AUDIO_CAPTURE,
417 std::string(), std::string());
418 scoped_refptr<WebRtcAudioCapturer> new_capturer(
419 WebRtcAudioCapturer::CreateCapturer(
420 -1, device, constraint_factory.CreateWebMediaConstraints(), NULL,
421 NULL));
422 scoped_refptr<MockCapturerSource> new_source(
423 new MockCapturerSource(new_capturer.get()));
424 EXPECT_CALL(*new_source.get(), OnInitialize(_, new_capturer.get(), -1));
425 EXPECT_CALL(*new_source.get(), SetAutomaticGainControl(true));
426 EXPECT_CALL(*new_source.get(), OnStart());
428 media::AudioParameters new_param(
429 media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
430 media::CHANNEL_LAYOUT_MONO, 44100, 16, 441);
431 new_capturer->SetCapturerSource(new_source, new_param);
433 // Setup the second audio track, connect it to the new capturer and start it.
434 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter_2(
435 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
436 scoped_ptr<WebRtcLocalAudioTrack> track_2(
437 new WebRtcLocalAudioTrack(adapter_2.get(), new_capturer, NULL));
438 track_2->Start();
440 // Verify the data flow by connecting the |sink_2| to |track_2|.
441 scoped_ptr<MockMediaStreamAudioSink> sink_2(new MockMediaStreamAudioSink());
442 base::WaitableEvent event(false, false);
443 EXPECT_CALL(*sink_2, CaptureData())
444 .Times(AnyNumber()).WillRepeatedly(Return());
445 EXPECT_CALL(*sink_2, FormatIsSet()).WillOnce(SignalEvent(&event));
446 track_2->AddSink(sink_2.get());
447 EXPECT_TRUE(event.TimedWait(TestTimeouts::tiny_timeout()));
449 // Stopping the new source will stop the second track.
450 event.Reset();
451 EXPECT_CALL(*new_source.get(), OnStop())
452 .Times(1).WillOnce(SignalEvent(&event));
453 new_capturer->Stop();
454 EXPECT_TRUE(event.TimedWait(TestTimeouts::tiny_timeout()));
456 // Stop the capturer of the first audio track.
457 EXPECT_CALL(*capturer_source_.get(), OnStop());
458 capturer_->Stop();
461 // Make sure a audio track can deliver packets with a buffer size smaller than
462 // 10ms when it is not connected with a peer connection.
463 TEST_F(WebRtcLocalAudioTrackTest, TrackWorkWithSmallBufferSize) {
464 // Setup a capturer which works with a buffer size smaller than 10ms.
465 media::AudioParameters params(media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
466 media::CHANNEL_LAYOUT_STEREO, 48000, 16, 128);
468 // Create a capturer with new source which works with the format above.
469 MockMediaConstraintFactory factory;
470 factory.DisableDefaultAudioConstraints();
471 scoped_refptr<WebRtcAudioCapturer> capturer(
472 WebRtcAudioCapturer::CreateCapturer(
473 -1, StreamDeviceInfo(MEDIA_DEVICE_AUDIO_CAPTURE, "", "",
474 params.sample_rate(), params.channel_layout(),
475 params.frames_per_buffer()),
476 factory.CreateWebMediaConstraints(), NULL, NULL));
477 scoped_refptr<MockCapturerSource> source(
478 new MockCapturerSource(capturer.get()));
479 EXPECT_CALL(*source.get(), OnInitialize(_, capturer.get(), -1));
480 EXPECT_CALL(*source.get(), SetAutomaticGainControl(true));
481 EXPECT_CALL(*source.get(), OnStart());
482 capturer->SetCapturerSource(source, params);
484 // Setup a audio track, connect it to the capturer and start it.
485 scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter(
486 WebRtcLocalAudioTrackAdapter::Create(std::string(), NULL));
487 scoped_ptr<WebRtcLocalAudioTrack> track(
488 new WebRtcLocalAudioTrack(adapter.get(), capturer, NULL));
489 track->Start();
491 // Verify the data flow by connecting the |sink| to |track|.
492 scoped_ptr<MockMediaStreamAudioSink> sink(new MockMediaStreamAudioSink());
493 base::WaitableEvent event(false, false);
494 EXPECT_CALL(*sink, FormatIsSet()).Times(1);
495 // Verify the sinks are getting the packets with an expecting buffer size.
496 #if defined(OS_ANDROID)
497 const int expected_buffer_size = params.sample_rate() / 100;
498 #else
499 const int expected_buffer_size = params.frames_per_buffer();
500 #endif
501 EXPECT_CALL(*sink, CaptureData())
502 .Times(AtLeast(1)).WillRepeatedly(SignalEvent(&event));
503 track->AddSink(sink.get());
504 EXPECT_TRUE(event.TimedWait(TestTimeouts::tiny_timeout()));
505 EXPECT_EQ(expected_buffer_size, sink->audio_params().frames_per_buffer());
507 // Stopping the new source will stop the second track.
508 EXPECT_CALL(*source.get(), OnStop()).Times(1);
509 capturer->Stop();
511 // Even though this test don't use |capturer_source_| it will be stopped
512 // during teardown of the test harness.
513 EXPECT_CALL(*capturer_source_.get(), OnStop());
516 } // namespace content