Allow audio system to handle synchronized low-latency audio I/O

media/audio/win/audio_low_latency_output_win_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 <windows.h>
 #include <mmsystem.h>
 
 #include "base/basictypes.h"
 #include "base/environment.h"
 #include "base/file_util.h"
@@ skipping 48 matching lines @@
 // Used to terminate a loop from a different thread than the loop belongs to.
 // |loop| should be a MessageLoopProxy.
 ACTION_P(QuitLoop, loop) {
   loop->PostTask(FROM_HERE, MessageLoop::QuitClosure());
 }
 
 class MockAudioSourceCallback : public AudioOutputStream::AudioSourceCallback {
  public:
   MOCK_METHOD2(OnMoreData, int(AudioBus* audio_bus,
                                AudioBuffersState buffers_state));
+  MOCK_METHOD3(OnMoreIOData, int(AudioBus* source,
+                                 AudioBus* dest,
+                                 AudioBuffersState buffers_state));
   MOCK_METHOD2(OnError, void(AudioOutputStream* stream, int code));
 };
 
 // This audio source implementation should be used for manual tests only since
 // it takes about 20 seconds to play out a file.
 class ReadFromFileAudioSource : public AudioOutputStream::AudioSourceCallback {
  public:
   explicit ReadFromFileAudioSource(const std::string& name)
     : pos_(0),
       previous_call_time_(base::Time::Now()),
@@ skipping 51 matching lines @@
       max_size = file_size() - pos_;
     int frames = max_size / (audio_bus->channels() * kBitsPerSample / 8);
     if (max_size) {
       audio_bus->FromInterleaved(
           file_->GetData() + pos_, frames, kBitsPerSample / 8);
       pos_ += max_size;
     }
     return frames;
   }
 
+  virtual int OnMoreIOData(AudioBus* source,
+                           AudioBus* dest,
+                           AudioBuffersState buffers_state) OVERRIDE {
+    NOTREACHED();
+    return 0;
+  }
+
   virtual void OnError(AudioOutputStream* stream, int code) {}
 
   int file_size() { return file_->GetDataSize(); }
 
  private:
   scoped_refptr<DecoderBuffer> file_;
   scoped_array<int> delta_times_;
   int pos_;
   base::Time previous_call_time_;
   FILE* text_file_;
@@ skipping 689 matching lines @@
 
   aos->Start(&source);
   loop.PostDelayedTask(FROM_HERE, MessageLoop::QuitClosure(),
                         TestTimeouts::action_timeout());
   loop.Run();
   aos->Stop();
   aos->Close();
 }
 
 }  // namespace media