Provide the DeviceManager service to the renderer directly, no app.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index e049d7926312c99bf786c3f126fe0c49a79476c7..0bb8cb9863fab8b9972e74da7aa54cf4bb510277 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -3855,9 +3855,7 @@ blink::WebBluetooth* RenderFrameImpl::bluetooth() {
 blink::WebUSBClient* RenderFrameImpl::usbClient() {
 #if !defined(OS_ANDROID)
   if (!usb_client_) {
-    mojo::ServiceProviderPtr device_services =
-        ConnectToApplication(GURL(device::kDevicesMojoAppUrl));
-    usb_client_.reset(new WebUSBClientImpl(device_services.Pass()));
+    usb_client_.reset(new WebUSBClientImpl(GetServiceRegistry()));
   }
 #endif
   return usb_client_.get();