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

content/renderer/usb/web_usb_client_impl.cc

 // Copyright 2015 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/usb/web_usb_client_impl.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/move.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/child/scoped_web_callbacks.h"
+#include "content/public/common/service_registry.h"
 #include "content/renderer/usb/type_converters.h"
 #include "content/renderer/usb/web_usb_device_impl.h"
-#include "device/devices_app/public/cpp/constants.h"
-#include "mojo/application/public/cpp/connect.h"
-#include "mojo/application/public/interfaces/shell.mojom.h"
 #include "third_party/WebKit/public/platform/WebCallbacks.h"
 #include "third_party/WebKit/public/platform/WebPassOwnPtr.h"
 #include "third_party/WebKit/public/platform/modules/webusb/WebUSBDeviceFilter.h"
 #include "third_party/WebKit/public/platform/modules/webusb/WebUSBDeviceInfo.h"
 #include "third_party/WebKit/public/platform/modules/webusb/WebUSBDeviceRequestOptions.h"
 #include "third_party/WebKit/public/platform/modules/webusb/WebUSBError.h"
 #include "third_party/mojo/src/mojo/public/cpp/bindings/array.h"
 #include "third_party/mojo/src/mojo/public/cpp/bindings/interface_request.h"
 
 namespace content {
@@ skipping 18 matching lines @@
     CallbacksType* callbacks) {
   return make_scoped_web_callbacks(
       callbacks,
       base::Bind(&RejectCallbacksWithError<CallbacksType>,
                  blink::WebUSBError(blink::WebUSBError::Error::Service,
                                     base::UTF8ToUTF16(kNoServiceError))));
 }
 
 void OnGetDevicesComplete(
     ScopedWebCallbacks<blink::WebUSBClientGetDevicesCallbacks> scoped_callbacks,
-    mojo::ServiceProvider* device_services,
+    device::usb::DeviceManager* device_manager,
     mojo::Array<device::usb::DeviceInfoPtr> results) {
-  device::usb::DeviceManagerPtr device_manager;
-  mojo::ConnectToService(device_services, &device_manager);
   blink::WebVector<blink::WebUSBDevice*>* devices =
       new blink::WebVector<blink::WebUSBDevice*>(results.size());
   for (size_t i = 0; i < results.size(); ++i) {
     device::usb::DevicePtr device;
     device_manager->GetDevice(results[i]->guid, mojo::GetProxy(&device));
     (*devices)[i] = new WebUSBDeviceImpl(
         device.Pass(), mojo::ConvertTo<blink::WebUSBDeviceInfo>(results[i]));
   }
   scoped_callbacks.PassCallbacks()->onSuccess(blink::adoptWebPtr(devices));
 }
 
 }  // namespace
 
-WebUSBClientImpl::WebUSBClientImpl(mojo::ServiceProviderPtr device_services)
-    : device_services_(device_services.Pass()) {
-  mojo::ConnectToService(device_services_.get(), &device_manager_);
+WebUSBClientImpl::WebUSBClientImpl(content::ServiceRegistry* service_registry) {
+  service_registry->ConnectToRemoteService(mojo::GetProxy(&device_manager_));
+  device_manager_.set_connection_error_handler(
+      [this]() { LOG(ERROR) << "Device manager connection failed."; });
 }
 
 WebUSBClientImpl::~WebUSBClientImpl() {}
 
 void WebUSBClientImpl::getDevices(
     blink::WebUSBClientGetDevicesCallbacks* callbacks) {
   auto scoped_callbacks = MakeScopedUSBCallbacks(callbacks);
   // TODO(rockot): Remove this once DeviceManager is updated. It should no
   // longer take enumeration options.
   device::usb::EnumerationOptionsPtr options =
       device::usb::EnumerationOptions::New();
   options->filters = mojo::Array<device::usb::DeviceFilterPtr>::New(0);
   device_manager_->GetDevices(
       options.Pass(),
       base::Bind(&OnGetDevicesComplete, base::Passed(&scoped_callbacks),
-                 base::Unretained(device_services_.get())));
+                 base::Unretained(device_manager_.get())));
 }
 
 void WebUSBClientImpl::requestDevice(
     const blink::WebUSBDeviceRequestOptions& options,
     blink::WebUSBClientRequestDeviceCallbacks* callbacks) {
   callbacks->onError(blink::WebUSBError(blink::WebUSBError::Error::Service,
                                         base::UTF8ToUTF16("Not implemented.")));
   delete callbacks;
 }
 
@@ skipping 28 matching lines @@
     const device::usb::DeviceInfoPtr& device_info =
         notification->devices_removed[i];
     device::usb::DevicePtr device;
     device_manager_->GetDevice(device_info->guid, mojo::GetProxy(&device));
     observer_->onDeviceDisconnected(blink::adoptWebPtr(new WebUSBDeviceImpl(
         device.Pass(), mojo::ConvertTo<blink::WebUSBDeviceInfo>(device_info))));
   }
 }
 
 }  // namespace content