Plumb |input_channels| all the way to AudioManager

media/audio/audio_device_thread.h

Index: media/audio/audio_device_thread.h
===================================================================
--- media/audio/audio_device_thread.h	(revision 181072)
+++ media/audio/audio_device_thread.h	(working copy)
@@ -37,7 +37,6 @@
   class Callback {
    public:
     Callback(const AudioParameters& audio_parameters,
-             int input_channels,
              base::SharedMemoryHandle memory,
              int memory_length);
     virtual ~Callback();
@@ -57,7 +56,6 @@
     // 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_;