Add a virtual beamforming audio device on ChromeOS.

chromeos/audio/audio_device.cc

Index: chromeos/audio/audio_device.cc
diff --git a/chromeos/audio/audio_device.cc b/chromeos/audio/audio_device.cc
index fd6ae45e42d878958b8a746ee7f6c90bcf6cf119..eeb693eb235e1fa6ee527f3d23e87ba743127e08 100644
--- a/chromeos/audio/audio_device.cc
+++ b/chromeos/audio/audio_device.cc
@@ -148,9 +148,9 @@ std::string AudioDevice::ToString() const {
   base::StringAppendF(&result,
                       "active = %s ",
                       active ? "true" : "false");
-  base::StringAppendF(&result,
-                      "plugged_time= %s ",
+  base::StringAppendF(&result, "plugged_time = %s ",
                       base::Uint64ToString(plugged_time).c_str());
+  base::StringAppendF(&result, "mic_positions = %s ", mic_positions.c_str());
 
   return result;
 }