Make AudioParameters a class instead of a struct

content/test/webrtc_audio_device_test.h

Index: content/test/webrtc_audio_device_test.h
diff --git a/content/test/webrtc_audio_device_test.h b/content/test/webrtc_audio_device_test.h
index 8b93e83e02ffbdfb3eb365de28287f28ec3d5b54..c4d2249dedfd79583c05de1b27b1d95c5ce270a6 100644
--- a/content/test/webrtc_audio_device_test.h
+++ b/content/test/webrtc_audio_device_test.h
@@ -14,6 +14,7 @@
 #include "base/message_loop.h"
 #include "content/browser/renderer_host/media/mock_media_observer.h"
 #include "content/renderer/mock_content_renderer_client.h"
+#include "media/base/channel_layout.h"
 #include "ipc/ipc_channel.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/webrtc/common_types.h"
@@ -111,7 +112,7 @@ class AudioUtilInterface {
   virtual double GetAudioHardwareSampleRate() = 0;
   virtual double GetAudioInputHardwareSampleRate(
       const std::string& device_id) = 0;
-  virtual uint32 GetAudioInputHardwareChannelCount(
+  virtual ChannelLayout GetAudioInputHardwareChannelLayout(
       const std::string& device_id) = 0;
 };
 
@@ -141,7 +142,7 @@ class WebRTCAudioDeviceTest
 
   void OnGetHardwareSampleRate(double* sample_rate);
   void OnGetHardwareInputSampleRate(double* sample_rate);
-  void OnGetHardwareInputChannelCount(uint32* channels);
+  void OnGetHardwareInputChannelLayout(ChannelLayout* channels);
 
   // IPC::Channel::Listener implementation.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;