Make AudioParameters a class instead of a struct

media/audio/linux/alsa_output.h

 // Copyright (c) 2011 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.
 //
 // Creates an output stream based on the ALSA PCM interface.
 //
 // On device write failure, the stream will move itself to an invalid state.
 // No more data will be pulled from the data source, or written to the device.
 // All calls to public API functions will either no-op themselves, or return an
 // error if possible.  Specifically, If the stream is in an error state, Open()
@@ skipping 105 matching lines @@
   friend std::ostream& operator<<(std::ostream& os, InternalState);
 
   // Functions to get another packet from the data source and write it into the
   // ALSA device.
   void BufferPacket(bool* source_exhausted);
   void WritePacket();
   void WriteTask();
   void ScheduleNextWrite(bool source_exhausted);
 
   // Utility functions for talking with the ALSA API.
-  static uint32 FramesToMicros(uint32 frames, uint32 sample_rate);
-  static uint32 FramesToMillis(uint32 frames, uint32 sample_rate);
+  static uint32 FramesToMicros(uint32 frames, uint32 samples_per_second);
+  static uint32 FramesToMillis(uint32 frames, uint32 samples_per_second);
   std::string FindDeviceForChannels(uint32 channels);
   snd_pcm_sframes_t GetAvailableFrames();
   snd_pcm_sframes_t GetCurrentDelay();
 
   // Attempts to find the best matching linux audio device for the given number
   // of channels.  This function will set |device_name_| and |should_downmix_|.
   snd_pcm_t* AutoSelectDevice(uint32 latency);
 
   // Functions to safeguard state transitions.  All changes to the object state
   // should go through these functions.
@@ skipping 20 matching lines @@
 
   // Changes the AudioSourceCallback to proxy calls to.  Pass in NULL to
   // release ownership of the currently registered callback.
   void set_source_callback(AudioSourceCallback* callback);
 
   // Configuration constants from the constructor.  Referenceable by all threads
   // since they are constants.
   const std::string requested_device_name_;
   const snd_pcm_format_t pcm_format_;
   const uint32 channels_;
-  const uint32 sample_rate_;
+  const uint32 samples_per_second_;
   const uint32 bytes_per_sample_;
   const uint32 bytes_per_frame_;
 
   // Device configuration data. Populated after OpenTask() completes.
   std::string device_name_;
   bool should_downmix_;
   uint32 packet_size_;
   uint32 micros_per_packet_;
   uint32 latency_micros_;
   uint32 bytes_per_output_frame_;
@@ skipping 25 matching lines @@
 
   AudioSourceCallback* source_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(AlsaPcmOutputStream);
 };
 
 MEDIA_EXPORT std::ostream& operator<<(std::ostream& os,
                                       AlsaPcmOutputStream::InternalState);
 
 #endif  // MEDIA_AUDIO_LINUX_ALSA_OUTPUT_H_