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

media/audio/audio_device_thread.h

Index: media/audio/audio_device_thread.h
===================================================================
--- media/audio/audio_device_thread.h	(revision 156123)
+++ media/audio/audio_device_thread.h	(working copy)
@@ -37,6 +37,7 @@
   class Callback {
    public:
     Callback(const AudioParameters& audio_parameters,
+             int input_channels,
              base::SharedMemoryHandle memory,
              int memory_length);
     virtual ~Callback();
@@ -56,11 +57,10 @@
     // The variables are 'const' since values are calculated/set in the
     // constructor and must never change.
     const AudioParameters audio_parameters_;
+    const int input_channels_;
     const int samples_per_ms_;
     const int bytes_per_ms_;
 
-    // Audio buffers that are allocated in InitializeOnAudioThread() based on
-    // info from audio_parameters_.
     base::SharedMemory shared_memory_;
     const int memory_length_;