Query native channel count in preferred parameters.

media/audio/pulse/audio_manager_pulse.h

 // Copyright 2013 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_PULSE_AUDIO_MANAGER_PULSE_H_
 #define MEDIA_AUDIO_PULSE_AUDIO_MANAGER_PULSE_H_
 
 #include <pulse/pulseaudio.h>
 #include <string>
 
@@ skipping 54 matching lines @@
 
   // Callback to get the devices' info like names, used by GetInputDevices().
   static void InputDevicesInfoCallback(pa_context* context,
                                        const pa_source_info* info,
                                        int error, void* user_data);
   static void OutputDevicesInfoCallback(pa_context* context,
                                         const pa_sink_info* info,
                                         int error, void* user_data);
 
   // Callback to get the native sample rate of PulseAudio, used by
   // GetNativeSampleRate().

[watk, 2016/09/15 21:21:52]

comment is out of date

[DaleCurtis, 2016/09/15 21:35:49]

Fixed.

-  static void SampleRateInfoCallback(pa_context* context,
-                                     const pa_server_info* info,
-                                     void* user_data);
+  static void AudioHardwareInfoCallback(pa_context* context,
+                                        const pa_server_info* info,
+                                        void* user_data);
 
   // Called by MakeLinearOutputStream and MakeLowLatencyOutputStream.
   AudioOutputStream* MakeOutputStream(const AudioParameters& params,
                                       const std::string& device_id);
 
   // Called by MakeLinearInputStream and MakeLowLatencyInputStream.
   AudioInputStream* MakeInputStream(const AudioParameters& params,
                                     const std::string& device_id);
 
-  // Gets the native sample rate of Pulse.
-  int GetNativeSampleRate();
+  // Updates |native_input_sample_rate_| and |native_channel_count_|.
+  void UpdateNativeAudioHardwareInfo();
 
   pa_threaded_mainloop* input_mainloop_;
   pa_context* input_context_;
   AudioDeviceNames* devices_;
   int native_input_sample_rate_;
+  int native_channel_count_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioManagerPulse);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_PULSE_AUDIO_MANAGER_PULSE_H_