Use AudioUnit instead of AudioDevice properties to get channel count.

media/audio/mac/audio_manager_mac.h

 // 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.
 
 #ifndef MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_
 #define MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_
 
 #include <AudioUnit/AudioUnit.h>
 #include <CoreAudio/AudioHardware.h>
 #include <stddef.h>
@@ skipping 56 matching lines @@
   void ReleaseOutputStream(AudioOutputStream* stream) override;
   void ReleaseInputStream(AudioInputStream* stream) override;
 
   // Called by AUHALStream::Close() before releasing the stream.
   // This method is a special contract between the real stream and the audio
   // manager and it ensures that we only try to increase the IO buffer size
   // for real streams and not for fake or mocked streams.
   void ReleaseOutputStreamUsingRealDevice(AudioOutputStream* stream,
                                           AudioDeviceID device_id);
 
-  static bool GetDeviceChannels(AudioDeviceID device,
-                                AudioObjectPropertyScope scope,
-                                int* channels);
-
   static int HardwareSampleRateForDevice(AudioDeviceID device_id);
   static int HardwareSampleRate();
 
   // OSX has issues with starting streams as the system goes into suspend and
   // immediately after it wakes up from resume.  See http://crbug.com/160920.
   // As a workaround we delay Start() when it occurs after suspend and for a
   // small amount of time after resume.
   //
   // Streams should consult ShouldDeferStreamStart() and if true check the value
   // again after |kStartDelayInSecsForPowerEvents| has elapsed. If false, the
@@ skipping 95 matching lines @@
   // Set to true in the destructor. Ensures that methods that touches native
   // Core Audio APIs are not executed during shutdown.
   bool in_shutdown_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerMac);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_MANAGER_MAC_H_