Use the task scheduler in the new Windows USB backend

extensions/shell/browser/shell_device_client.cc

 // Copyright 2014 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 "extensions/shell/browser/shell_device_client.h"
 
 #include "content/public/browser/browser_thread.h"
 #include "device/hid/hid_service.h"
 #include "device/usb/usb_service.h"
 
@@ skipping 14 matching lines @@
     usb_service_->Shutdown();
   if (hid_service_)
     hid_service_->Shutdown();
 #if DCHECK_IS_ON()
   did_shutdown_ = true;
 #endif
 }
 
 device::UsbService* ShellDeviceClient::GetUsbService() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-
-  if (!usb_service_) {
-    usb_service_ = device::UsbService::Create(
-        BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE));
-  }
+  if (!usb_service_)
+    usb_service_ = device::UsbService::Create();
   return usb_service_.get();
 }
 
 device::HidService* ShellDeviceClient::GetHidService() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (!hid_service_)
     hid_service_ = device::HidService::Create();
   return hid_service_.get();
 }
 
 }  // namespace extensions