Stop enqueueing data to output audio device if consecutive empty buffers are received

media/audio/android/audio_android_unittest.cc

Index: media/audio/android/audio_android_unittest.cc
diff --git a/media/audio/android/audio_android_unittest.cc b/media/audio/android/audio_android_unittest.cc
index b8ebccf3b2b5a4e1c0694d6bafd265ecef4b3c0c..395a5d09ffdb58c9c334b5385a5de93fb940b626 100644
--- a/media/audio/android/audio_android_unittest.cc
+++ b/media/audio/android/audio_android_unittest.cc
@@ -404,6 +404,41 @@ class FullDuplexAudioSinkSource
   DISALLOW_COPY_AND_ASSIGN(FullDuplexAudioSinkSource);
 };
 
+// Implements AudioOutputStream::AudioSourceCallback and provides empty audio
+// data.
+class EmptyAudioSource : public AudioOutputStream::AudioSourceCallback {
+ public:
+  EmptyAudioSource(base::WaitableEvent* event, int size)
+      : event_(event), remaining_size_(size) {}
+  ~EmptyAudioSource() override {}
+
+  // AudioOutputStream::AudioSourceCallback implementation.
+  int OnMoreData(AudioBus* audio_bus, uint32 total_bytes_delay) override {
+    audio_bus->Zero();
+    int max_size =
+        audio_bus->frames() * audio_bus->channels() * kBytesPerSample;
+    bool stop_playing = false;
+    if (max_size > remaining_size_) {
+      stop_playing = true;
+      max_size = remaining_size_;
+    }
+    remaining_size_ -= max_size;
+    // Set event to ensure that the test can stop.
+    if (stop_playing)
+      event_->Signal();
+
+    return max_size / (audio_bus->channels() * kBytesPerSample);
+  }
+
+  void OnError(AudioOutputStream* stream) override {}
+
+ private:
+  base::WaitableEvent* event_;
+  int remaining_size_;
+
+  DISALLOW_COPY_AND_ASSIGN(EmptyAudioSource);
+};
+
 // Test fixture class for tests which only exercise the output path.
 class AudioAndroidOutputTest : public testing::Test {
  public:
@@ -863,6 +898,29 @@ TEST_F(AudioAndroidOutputTest, DISABLED_RunOutputStreamWithFileAsSource) {
   StopAndCloseAudioOutputStreamOnAudioThread();
 }
 
+// Play empty data and verify that the data are consumed properly.
+TEST_F(AudioAndroidOutputTest, RunOutputStreamWithEmptySource) {
+  GetDefaultOutputStreamParametersOnAudioThread();
+  const AudioParameters params = audio_output_parameters();
+  DVLOG(1) << params;
+  MakeAudioOutputStreamOnAudioThread(params);
+
+  base::WaitableEvent event(false, false);
+  int size = 100000;
+  EmptyAudioSource source(&event, size);
+  base::TimeTicks start_time = base::TimeTicks::Now();
+
+  OpenAndStartAudioOutputStreamOnAudioThread(&source);
+  EXPECT_TRUE(event.TimedWait(TestTimeouts::action_max_timeout()));
+  // Verify that all the data are consumed as if they are passed through audio
+  // hardware.
+  base::TimeDelta time_passed = base::TimeTicks::Now() - start_time;
+  int estimated_consumption_time_ms = (size * 1000) /
+      (params.channels() * params.sample_rate() * kBytesPerSample);
+  EXPECT_LE(estimated_consumption_time_ms, time_passed.InMilliseconds());
+  StopAndCloseAudioOutputStreamOnAudioThread();
+}
+
 // Start input streaming and run it for ten seconds while recording to a
 // local audio file.
 // NOTE: this test requires user interaction and is not designed to run as an