Adding microphone volume support to chrome.

media/audio/linux/alsa_wrapper.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.
 //
 // AlsaWrapper is a simple stateless class that wraps the alsa library commands
 // we want to use.  It's purpose is to allow injection of a mock so that the
 // higher level code is testable.
 
 #include <alsa/asoundlib.h>
 
@@ skipping 27 matching lines @@
                            snd_pcm_access_t access, unsigned int channels,
                            unsigned int rate, int soft_resample,
                            unsigned int latency);
   virtual int PcmGetParams(snd_pcm_t* handle, snd_pcm_uframes_t* buffer_size,
                            snd_pcm_uframes_t* period_size);
   virtual const char* PcmName(snd_pcm_t* handle);
   virtual snd_pcm_sframes_t PcmAvailUpdate(snd_pcm_t* handle);
   virtual snd_pcm_state_t PcmState(snd_pcm_t* handle);
   virtual int PcmStart(snd_pcm_t* handle);
 
+  virtual int MixerOpen(snd_mixer_t** mixer, int mode);
+  virtual int MixerAttach(snd_mixer_t* mixer, const char *name);
+  virtual int MixerElementRegister(snd_mixer_t* mixer,
+                                   struct snd_mixer_selem_regopt* options,
+                                   snd_mixer_class_t** classp);
+  virtual void MixerFree(snd_mixer_t* mixer);
+  virtual int MixerDetach(snd_mixer_t* mixer, const char* name);
+  virtual int MixerClose(snd_mixer_t* mixer);
+  virtual int MixerLoad(snd_mixer_t *mixer);
+  virtual snd_mixer_elem_t* MixerFirstElem(snd_mixer_t *mixer);
+  virtual snd_mixer_elem_t* MixerNextElem(snd_mixer_elem_t *elem);
+  virtual int MixerSelemIsActive(snd_mixer_elem_t *elem);
+  virtual const char* MixerSelemName(snd_mixer_elem_t *elem);
+  virtual int MixerSelemSetCaptureVolumeAll(snd_mixer_elem_t *elem, long value);
+  virtual int MixerSelemGetCaptureVolume(snd_mixer_elem_t *elem,
+                                         snd_mixer_selem_channel_id_t channel,
+                                         long *value);
+  virtual int MixerSelemHasCaptureVolume(snd_mixer_elem_t *elem);
+  virtual int MixerSelemGetCaptureVolumeRange(snd_mixer_elem_t *elem,
+                                              long *min, long *max);
+
   virtual const char* StrError(int errnum);
 
  private:
   int ConfigureHwParams(snd_pcm_t* handle, snd_pcm_hw_params_t* hw_params,
                         snd_pcm_format_t format, snd_pcm_access_t access,
                         unsigned int channels, unsigned int rate,
                         int soft_resample, unsigned int latency);
   DISALLOW_COPY_AND_ASSIGN(AlsaWrapper);
 };