Use the task scheduler in the new Windows USB backend

device/test/test_device_client.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 "device/test/test_device_client.h"
 
 #include "base/single_thread_task_runner.h"
 #include "build/build_config.h"
 
 // This file unconditionally includes these headers despite conditionally
 // depending on the corresponding targets. The code below needs the destructors
 // of the classes defined even when the classes are never instantiated.
 // TODO: This should probably be done more explicitly to avoid ambiguity.
 #include "device/hid/hid_service.h"  // nogncheck
 #include "device/usb/usb_service.h"  // nogncheck
 
 namespace device {
 
-TestDeviceClient::TestDeviceClient(
-    scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner)
-    : blocking_task_runner_(blocking_task_runner) {}
+TestDeviceClient::TestDeviceClient() = default;
 
 TestDeviceClient::~TestDeviceClient() {
   if (hid_service_)
     hid_service_->Shutdown();
   if (usb_service_)
     usb_service_->Shutdown();
 }
 
 HidService* TestDeviceClient::GetHidService() {
 #if !defined(OS_ANDROID) && !defined(OS_IOS) && \
     !(defined(OS_LINUX) && !defined(USE_UDEV))
   if (!hid_service_)
     hid_service_ = HidService::Create();
 #endif
   return hid_service_.get();
 }
 
 UsbService* TestDeviceClient::GetUsbService() {
 #if !defined(OS_ANDROID) && !defined(OS_IOS)
-  if (!usb_service_) {
-    usb_service_ = UsbService::Create(blocking_task_runner_);
-  }
+  if (!usb_service_)
+    usb_service_ = UsbService::Create();
 #endif
   return usb_service_.get();
 }
 
 }  // namespace device