add audio-buffer-size command line flag support to the input audio for all the platforms

media/audio/alsa/audio_manager_alsa.cc

 // Copyright 2013 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 "media/audio/alsa/audio_manager_alsa.h"
 
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
@@ skipping 89 matching lines @@
   DCHECK(device_names->empty());
   GetAlsaAudioDevices(kStreamCapture, device_names);
 }
 
 void AudioManagerAlsa::GetAudioOutputDeviceNames(
     AudioDeviceNames* device_names) {
   DCHECK(device_names->empty());
   GetAlsaAudioDevices(kStreamPlayback, device_names);
 }
 
-AudioParameters AudioManagerAlsa::GetInputStreamParameters(
-    const std::string& device_id) {
+AudioParameters AudioManagerAlsa::GetPreferredInputStreamParameters(
+    const std::string& input_device_id,
+    const AudioParameters& input_params) {
   static const int kDefaultInputBufferSize = 1024;
+  ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
+  int sample_rate = kDefaultSampleRate;
+  int buffer_size = kDefaultInputBufferSize;
+  int bits_per_sample = 16;
+  if (input_params.IsValid()) {
+    sample_rate = input_params.sample_rate();
+    bits_per_sample = input_params.bits_per_sample();
+    channel_layout = input_params.channel_layout();
+    buffer_size = input_params.frames_per_buffer();
+  }
 
   return AudioParameters(
-      AudioParameters::AUDIO_PCM_LOW_LATENCY, CHANNEL_LAYOUT_STEREO,
-      kDefaultSampleRate, 16, kDefaultInputBufferSize);
+      AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout,
+      sample_rate, bits_per_sample, buffer_size);
 }
 
 void AudioManagerAlsa::GetAlsaAudioDevices(
     StreamType type,
     media::AudioDeviceNames* device_names) {
   // Constants specified by the ALSA API for device hints.
   static const char kPcmInterfaceName[] = "pcm";
   int card = -1;
 
   // Loop through the sound cards to get ALSA device hints.
@@ skipping 224 matching lines @@
       AlsaPcmInputStream::kAutoSelectDevice : device_id;
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kAlsaInputDevice)) {
     device_name = CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
         switches::kAlsaInputDevice);
   }
 
   return new AlsaPcmInputStream(this, device_name, params, wrapper_.get());
 }
 
 }  // namespace media