Make AudioParameters a class instead of a struct

media/audio/audio_input_volume_unittest.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 <cmath>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/win/scoped_com_initializer.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager_base.h"
@@ skipping 28 matching lines @@
   bool HasDeviceVolumeControl(AudioInputStream* stream) {
     if (!stream)
       return false;
 
     return (stream->GetMaxVolume() != 0.0);
   }
 
   AudioInputStream* CreateAndOpenStream(const std::string& device_id) {
     AudioParameters::Format format = AudioParameters::AUDIO_PCM_LOW_LATENCY;
     ChannelLayout channel_layout =
-        (media::GetAudioInputHardwareChannelCount(device_id) == 1) ?
-            CHANNEL_LAYOUT_MONO : CHANNEL_LAYOUT_STEREO;
+        media::GetAudioInputHardwareChannelLayout(device_id);
     int bits_per_sample = 16;
     int sample_rate =
         static_cast<int>(media::GetAudioInputHardwareSampleRate(device_id));
     int samples_per_packet = 0;
 #if defined(OS_MACOSX)
     samples_per_packet = (sample_rate / 100);
 #elif defined(OS_LINUX) || defined(OS_OPENBSD)
     samples_per_packet = (sample_rate / 100);
 #elif defined(OS_WIN)
     if (sample_rate == 44100)
@@ skipping 90 matching lines @@
     EXPECT_NEAR(current_volume, new_volume, 0.25 * max_volume);
 
     // Restores the volume to the original value.
     ais->SetVolume(original_volume);
     current_volume = ais->GetVolume();
     EXPECT_EQ(original_volume, current_volume);
 
     ais->Close();
   }
 }