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..bd6011823ec6dd68fa5f8d790963d792f15e2b50 100644
--- a/media/audio/alsa/audio_manager_alsa.cc
+++ b/media/audio/alsa/audio_manager_alsa.cc
@@ -52,6 +52,10 @@ static const char* kInvalidAudioInputDevices[] = {
   "surround",
 };
 
+namespace {
+const char kAudioManagerName[] = "ALSA";
+}
+
 // static
 void AudioManagerAlsa::ShowLinuxAudioInputSettings() {
   std::unique_ptr<base::Environment> env(base::Environment::Create());
@@ -127,6 +131,10 @@ AudioParameters AudioManagerAlsa::GetInputStreamParameters(
       kDefaultSampleRate, 16, kDefaultInputBufferSize);
 }
 
+const char* AudioManagerAlsa::GetName() {
+  return kAudioManagerName;
+}
+
 void AudioManagerAlsa::GetAlsaAudioDevices(StreamType type,
                                            AudioDeviceNames* device_names) {
   // Constants specified by the ALSA API for device hints.