Use the task scheduler in the new Windows USB backend

extensions/shell/browser/shell_device_client.cc

Index: extensions/shell/browser/shell_device_client.cc
diff --git a/extensions/shell/browser/shell_device_client.cc b/extensions/shell/browser/shell_device_client.cc
index 9973d5b01d0384ed09029c3145ca13f8899d69df..a7af1d5010bdcd6c53266f315aa278ff65ea8fd9 100644
--- a/extensions/shell/browser/shell_device_client.cc
+++ b/extensions/shell/browser/shell_device_client.cc
@@ -32,11 +32,8 @@ void ShellDeviceClient::Shutdown() {
 
 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();
 }