Add a virtual beamforming audio device on ChromeOS.

content/public/common/media_stream_request.cc

Index: content/public/common/media_stream_request.cc
diff --git a/content/public/common/media_stream_request.cc b/content/public/common/media_stream_request.cc
index 0a35bd783bf7b8c16fabf293022c9ba92f971869..7eadf9a6c1338032c6bb499734e701fea98a5ac9 100644
--- a/content/public/common/media_stream_request.cc
+++ b/content/public/common/media_stream_request.cc
@@ -83,6 +83,20 @@ const MediaStreamDevice* MediaStreamDevices::FindById(
   return NULL;
 }
 
+MediaStreamDevice::AudioDeviceParameters::AudioDeviceParameters()
+    : sample_rate(), channel_layout(), frames_per_buffer(), effects() {}
+
+MediaStreamDevice::AudioDeviceParameters::AudioDeviceParameters(
+    int sample_rate,
+    int channel_layout,
+    int frames_per_buffer)
+    : sample_rate(sample_rate),
+      channel_layout(channel_layout),
+      frames_per_buffer(frames_per_buffer),
+      effects() {}
+
+MediaStreamDevice::AudioDeviceParameters::~AudioDeviceParameters() {}
+
 MediaStreamRequest::MediaStreamRequest(
     int render_process_id,
     int render_frame_id,