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

media/audio/win/audio_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/base_paths.h"
 #include "base/file_util.h"
@@ skipping 36 matching lines @@
         had_error_(0) {
   }
   // AudioSourceCallback::OnMoreData implementation:
   virtual int OnMoreData(AudioBus* audio_bus,
                          AudioBuffersState buffers_state) {
     ++callback_count_;
     // Touch the channel memory value to make sure memory is good.
     audio_bus->Zero();
     return audio_bus->frames();
   }
+  virtual int OnMoreIOData(AudioBus* source,
+                           AudioBus* dest,
+                           AudioBuffersState buffers_state) {
+    NOTREACHED();
+    return 0;
+  }
   // AudioSourceCallback::OnError implementation:
   virtual void OnError(AudioOutputStream* stream, int code) {
     ++had_error_;
   }
   // Returns how many times OnMoreData() has been called.
   int callback_count() const {
     return callback_count_;
   }
   // Returns how many times the OnError callback was called.
   int had_error() const {
@@ skipping 28 matching lines @@
   }
  private:
   int laggy_after_buffer_;
   int lag_in_ms_;
 };
 
 class MockAudioSource : 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));
 
   static int ClearData(AudioBus* audio_bus, AudioBuffersState buffers_state) {
     audio_bus->Zero();
     return audio_bus->frames();
   }
 };
 
 // Helper class to memory map an entire file. The mapping is read-only. Don't
 // use for gigabyte-sized files. Attempts to write to this memory generate
@@ skipping 467 matching lines @@
 
   // AudioSourceCallback::OnMoreData implementation:
   virtual int OnMoreData(AudioBus* audio_bus,
                          AudioBuffersState buffers_state) {
     socket_->Send(&buffers_state, sizeof(buffers_state));
     uint32 size = socket_->Receive(data_.get(), data_size_);
     DCHECK_EQ(static_cast<size_t>(size) % sizeof(*audio_bus_->channel(0)), 0U);
     audio_bus_->CopyTo(audio_bus);
     return audio_bus_->frames();
   }
+  virtual int OnMoreIOData(AudioBus* source,
+                           AudioBus* dest,
+                           AudioBuffersState buffers_state) {
+    NOTREACHED();
+    return 0;
+  }
   // AudioSourceCallback::OnError implementation:
   virtual void OnError(AudioOutputStream* stream, int code) {
   }
 
  private:
   base::SyncSocket* socket_;
   int data_size_;
   scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> data_;
   scoped_ptr<AudioBus> audio_bus_;
 };
@@ skipping 84 matching lines @@
   oas->Start(&source);
 
   ::WaitForSingleObject(thread, INFINITE);
   ::CloseHandle(thread);
 
   oas->Stop();
   oas->Close();
 }
 
 }  // namespace media