Remove incorrect DCHECK for suspend muted audio feature.

When we get bad device info, we don't setup the NullAudioSink for
the suspend muted audio feature (we're already on a NullAudioSink).

R=tmathmeyer

Fixed: 1110780
Test: New unittest.
Change-Id: I258db545723c0cdf4ab6a8a4ca319c4c88da8e83
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2327250
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Ted Meyer <tmathmeyer@chromium.org>
Auto-Submit: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Ted Meyer <tmathmeyer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792916}

media/renderers/audio_renderer_impl.cc

@@ -661,7 +661,8 @@ void AudioRendererImpl::OnAudioDecoderStreamInitialized(bool success) {
       null_sink_->Start();  // Does nothing but reduce state bookkeeping.
       real_sink_needs_start_ = true;
     } else {
-      DCHECK(!base::FeatureList::IsEnabled(kSuspendMutedAudio));
+      // Even when kSuspendMutedAudio is enabled, we can hit this path if we are
+      // exclusively using NullAudioSink due to OnDeviceInfoReceived() failure.
       sink_->Start();
       sink_->Pause();  // Sinks play on start.
     }
@@ -733,7 +734,8 @@ void AudioRendererImpl::SetVolume(float volume) {
 
   sink_->SetVolume(volume);
   if (!null_sink_) {
-    DCHECK(!base::FeatureList::IsEnabled(kSuspendMutedAudio));
+    // Either null sink suspension is not enabled or we're already on the null
+    // sink due to failing to get device parameters.
     return;
   }
 

media/renderers/audio_renderer_impl_unittest.cc

@@ -1401,6 +1401,47 @@ TEST_F(AudioRendererImplTest, BitstreamEndOfStream) {
   SetMediaClient(nullptr);
 }
 
+TEST_F(AudioRendererImplTest, MutedPlaybackBadDeviceInfo) {
+  base::test::ScopedFeatureList scoped_feature_list_;
+  scoped_feature_list_.InitAndEnableFeature(kSuspendMutedAudio);
+
+  mock_sink_ = base::MakeRefCounted<MockAudioRendererSink>(
+      std::string(), OUTPUT_DEVICE_STATUS_ERROR_NOT_AUTHORIZED,
+      AudioParameters());
+  renderer_ = std::make_unique<AudioRendererImpl>(
+      main_thread_task_runner_, mock_sink_.get(),
+      base::BindRepeating(&AudioRendererImplTest::CreateAudioDecoderForTest,
+                          base::Unretained(this)),
+      &media_log_, nullptr);
+  testing::Mock::VerifyAndClearExpectations(&demuxer_stream_);
+  ConfigureDemuxerStream(true);
+
+  EXPECT_CALL(*mock_sink_, SetVolume(0)).Times(0);
+  renderer_->SetVolume(0);
+
+  // Playback startup should use never touch our passed in sink, since an
+  // internal NullAudioSink is always used for bad device info.
+  EXPECT_CALL(*mock_sink_, Start()).Times(0);
+  Initialize();
+  Preroll();
+  StartTicking();
+
+  EXPECT_CALL(*mock_sink_, Pause()).Times(0);
+  StopTicking();
+  EXPECT_CALL(*mock_sink_, Play()).Times(0);
+  StartTicking();
+  testing::Mock::VerifyAndClearExpectations(mock_sink_.get());
+
+  EXPECT_CALL(*mock_sink_, SetVolume(1)).Times(0);
+  EXPECT_CALL(*mock_sink_, Start()).Times(0);
+  EXPECT_CALL(*mock_sink_, Play()).Times(0);
+  renderer_->SetVolume(1);
+
+  EXPECT_CALL(*mock_sink_, Pause()).Times(0);
+  StopTicking();
+  EXPECT_CALL(*mock_sink_, Stop()).Times(0);
+}
+
 TEST_F(AudioRendererImplTest, BasicMutedPlayback) {
   base::test::ScopedFeatureList scoped_feature_list_;
   scoped_feature_list_.InitAndEnableFeature(kSuspendMutedAudio);