Add a virtual beamforming audio device on ChromeOS.

content/renderer/media/webrtc_audio_renderer.cc

Index: content/renderer/media/webrtc_audio_renderer.cc
diff --git a/content/renderer/media/webrtc_audio_renderer.cc b/content/renderer/media/webrtc_audio_renderer.cc
index 9d2b2011058510573517792046d959d8736b32fd..669faf9854eb5f5296abf421d145fcf41084ef64 100644
--- a/content/renderer/media/webrtc_audio_renderer.cc
+++ b/content/renderer/media/webrtc_audio_renderer.cc
@@ -199,8 +199,11 @@ WebRtcAudioRenderer::WebRtcAudioRenderer(
       audio_delay_milliseconds_(0),
       fifo_delay_milliseconds_(0),
       sink_params_(media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
-                   media::CHANNEL_LAYOUT_STEREO, sample_rate, 16,
+                   media::CHANNEL_LAYOUT_STEREO,
+                   sample_rate,
+                   16,
                    frames_per_buffer,
+                   "",
                    GetCurrentDuckingFlag(source_render_frame_id)),
       render_callback_count_(0) {
   WebRtcLogMessage(base::StringPrintf(