Adding ArcBridge Interface for Volume Update Requests

components/arc/audio/arc_audio_bridge.cc

Index: components/arc/audio/arc_audio_bridge.cc
diff --git a/components/arc/audio/arc_audio_bridge.cc b/components/arc/audio/arc_audio_bridge.cc
index 9a0da08829a5e88cb2ac299b71b027dd542637fd..f0e50a25c2507fb8ee91d4efbaa4abafeed0836c 100644
--- a/components/arc/audio/arc_audio_bridge.cc
+++ b/components/arc/audio/arc_audio_bridge.cc
@@ -39,6 +39,14 @@ void ArcAudioBridge::ShowVolumeControls() {
   ash::TrayAudio::ShowPopUpVolumeView();
 }
 
+void ArcAudioBridge::OnSystemVolumeUpdateRequest(float volume) {
+  cras_audio_handler_->SetOutputVolumePercent(volume);
+  bool is_muted =
+      volume <= cras_audio_handler_->GetOutputDefaultVolumeMuteThreshold();
+  if (cras_audio_handler_->IsOutputMuted() != is_muted)
+    cras_audio_handler_->SetOutputMute(is_muted);
+}
+
 void ArcAudioBridge::OnAudioNodesChanged() {
   uint64_t output_id = cras_audio_handler_->GetPrimaryActiveOutputNode();
   const chromeos::AudioDevice* output_device =