Move the device enumerate/open/close work to device thread from IO thread

content/browser/renderer_host/media/media_stream_dispatcher_host.cc

Index: content/browser/renderer_host/media/media_stream_dispatcher_host.cc
diff --git a/content/browser/renderer_host/media/media_stream_dispatcher_host.cc b/content/browser/renderer_host/media/media_stream_dispatcher_host.cc
index 7ae8e2d25b1b712e9c4d9fe5427f81f3c5bda386..254cf2dade9a0374d161b870b516cd5fc3145921 100644
--- a/content/browser/renderer_host/media/media_stream_dispatcher_host.cc
+++ b/content/browser/renderer_host/media/media_stream_dispatcher_host.cc
@@ -26,11 +26,9 @@ struct MediaStreamDispatcherHost::StreamRequest {
 
 MediaStreamDispatcherHost::MediaStreamDispatcherHost(
     content::ResourceContext* resource_context,
-    int render_process_id,
-    media::AudioManager* audio_manager)
+    int render_process_id)
     : resource_context_(resource_context),
-      render_process_id_(render_process_id),
-      audio_manager_(audio_manager) {
+      render_process_id_(render_process_id) {
 }
 
 void MediaStreamDispatcherHost::StreamGenerated(
@@ -273,8 +271,7 @@ void MediaStreamDispatcherHost::OnOpenDevice(
 }
 
 MediaStreamManager* MediaStreamDispatcherHost::manager() {
-  return MediaStreamManager::GetForResourceContext(
-      resource_context_, audio_manager_);
+  return MediaStreamManager::GetForResourceContext(resource_context_);
 }
 
 }  // namespace media_stream