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

content/renderer/render_frame_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 
 #include "base/auto_reset.h"
@@ skipping 3837 matching lines @@
     bluetooth_.reset(new WebBluetoothImpl(
         ChildThreadImpl::current()->thread_safe_sender(), routing_id_));
   }
 
   return bluetooth_.get();
 }
 
 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();
 }
 
 #if defined(ENABLE_WEBVR)
 blink::WebVRClient* RenderFrameImpl::webVRClient() {
   if (!vr_dispatcher_)
     vr_dispatcher_.reset(new VRDispatcher(GetServiceRegistry()));
 
@@ skipping 1266 matching lines @@
   mojo::ServiceProviderPtr service_provider;
   mojo::URLRequestPtr request(mojo::URLRequest::New());
   request->url = mojo::String::From(url);
   mojo_shell_->ConnectToApplication(request.Pass(), GetProxy(&service_provider),
                                     nullptr, nullptr,
                                     base::Bind(&OnGotContentHandlerID));
   return service_provider.Pass();
 }
 
 }  // namespace content