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

media/audio/audio_device_thread.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 "media/audio/audio_device_thread.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 159 matching lines @@
     base::AutoLock auto_lock(callback_lock_);
     if (callback_)
       callback_->Process(pending_data);
   }
 }
 
 // AudioDeviceThread::Callback implementation
 
 AudioDeviceThread::Callback::Callback(
     const AudioParameters& audio_parameters,
+    int input_channels,
     base::SharedMemoryHandle memory, int memory_length)
     : audio_parameters_(audio_parameters),
+      input_channels_(input_channels),
       samples_per_ms_(audio_parameters.sample_rate() / 1000),
       bytes_per_ms_(audio_parameters.channels() *
                     (audio_parameters_.bits_per_sample() / 8) *
                     samples_per_ms_),
       shared_memory_(memory, false),
       memory_length_(memory_length) {
   CHECK_NE(bytes_per_ms_, 0);  // Catch division by zero early.
   CHECK_NE(samples_per_ms_, 0);
 }
 
 AudioDeviceThread::Callback::~Callback() {}
 
 void AudioDeviceThread::Callback::InitializeOnAudioThread() {
   MapSharedMemory();
   DCHECK(shared_memory_.memory() != NULL);
 }
 
 }  // namespace media.