Log audio system used to WebRTC log.

media/audio/alsa/audio_manager_alsa.cc

Index: media/audio/alsa/audio_manager_alsa.cc
diff --git a/media/audio/alsa/audio_manager_alsa.cc b/media/audio/alsa/audio_manager_alsa.cc
index 3886d668c9cfea0965d4b61c967889ec7077010d..72c48e3327a88062e87938819bb471d82ff7e6cd 100644
--- a/media/audio/alsa/audio_manager_alsa.cc
+++ b/media/audio/alsa/audio_manager_alsa.cc
@@ -127,6 +127,10 @@ AudioParameters AudioManagerAlsa::GetInputStreamParameters(
       kDefaultSampleRate, 16, kDefaultInputBufferSize);
 }
 
+const char* AudioManagerAlsa::GetName() {
+  return "ALSA";
+}
+
 void AudioManagerAlsa::GetAlsaAudioDevices(StreamType type,
                                            AudioDeviceNames* device_names) {
   // Constants specified by the ALSA API for device hints.