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

media/audio/openbsd/audio_manager_openbsd.cc

Index: media/audio/openbsd/audio_manager_openbsd.cc
diff --git a/media/audio/openbsd/audio_manager_openbsd.cc b/media/audio/openbsd/audio_manager_openbsd.cc
index ec482d8b7cd771730469fa7b8d9731de061046b9..9b9f2edbaac47ffbd8b91803ca45f6bc57b2dd9e 100644
--- a/media/audio/openbsd/audio_manager_openbsd.cc
+++ b/media/audio/openbsd/audio_manager_openbsd.cc
@@ -55,17 +55,29 @@ bool AudioManagerOpenBSD::HasAudioInputDevices() {
   return HasAudioHardware();
 }
 
-AudioParameters AudioManagerOpenBSD::GetInputStreamParameters(
-    const std::string& device_id) {
+AudioParameters AudioManagerOpenBSD::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 = std::min(buffer_size, input_params.frames_per_buffer());
+  }
+
   int user_buffer_size = GetUserBufferSize();
-  int buffer_size = user_buffer_size ?
-      user_buffer_size : kDefaultInputBufferSize;
+  if (user_buffer_size)
+    buffer_size = user_buffer_size;
 
   return AudioParameters(
-      AudioParameters::AUDIO_PCM_LOW_LATENCY, CHANNEL_LAYOUT_STEREO,
-      kDefaultSampleRate, 16, buffer_size);
+      AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout,
+      sample_rate, bits_per_sample, buffer_size);
 }
 
 AudioManagerOpenBSD::AudioManagerOpenBSD(AudioLogFactory* audio_log_factory)