Make AudioParameters a class instead of a struct

media/audio/mac/audio_low_latency_input_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.
 //
 // Implementation of AudioInputStream for Mac OS X using the special AUHAL
 // input Audio Unit present in OS 10.4 and later.
 // The AUHAL input Audio Unit is for low-latency audio I/O.
 //
 // Overview of operation:
 //
@@ skipping 48 matching lines @@
   // Implementation of AudioInputStream.
   virtual bool Open() OVERRIDE;
   virtual void Start(AudioInputCallback* callback) OVERRIDE;
   virtual void Stop() OVERRIDE;
   virtual void Close() OVERRIDE;
   virtual double GetMaxVolume() OVERRIDE;
   virtual void SetVolume(double volume) OVERRIDE;
   virtual double GetVolume() OVERRIDE;
 
   // Returns the current hardware sample rate for the default input device.
-  MEDIA_EXPORT static double HardwareSampleRate();
+  MEDIA_EXPORT static int HardwareSampleRate();
 
   bool started() const { return started_; }
   AudioUnit audio_unit() { return audio_unit_; }
   AudioBufferList* audio_buffer_list() { return &audio_buffer_list_; }
 
  private:
   // AudioOutputUnit callback.
   static OSStatus InputProc(void* user_data,
                             AudioUnitRenderActionFlags* flags,
                             const AudioTimeStamp* time_stamp,
@@ skipping 57 matching lines @@
   double hardware_latency_frames_;
 
   // The number of channels in each frame of audio data, which is used
   // when querying the volume of each channel.
   int number_of_channels_in_frame_;
 
   DISALLOW_COPY_AND_ASSIGN(AUAudioInputStream);
 };
 
 #endif  // MEDIA_AUDIO_MAC_AUDIO_LOW_LATENCY_INPUT_MAC_H_