Use the task scheduler in the new Windows USB backend

device/usb/usb_service_unittest.cc

Index: device/usb/usb_service_unittest.cc
diff --git a/device/usb/usb_service_unittest.cc b/device/usb/usb_service_unittest.cc
index d3991ad7f8573e9726b74219a48b32a15b12274c..07594a4d4b27ab281649e7bb35a32a30b8d1f3ea 100644
--- a/device/usb/usb_service_unittest.cc
+++ b/device/usb/usb_service_unittest.cc
@@ -27,11 +27,8 @@ class UsbServiceTest : public ::testing::Test {
   UsbServiceTest()
       : scoped_task_environment_(
             base::test::ScopedTaskEnvironment::MainThreadType::UI),
-        io_thread_(base::TestIOThread::kAutoStart) {}
-
-  void SetUp() override {
-    device_client_.reset(new TestDeviceClient(io_thread_.task_runner()));
-  }
+        io_thread_(base::TestIOThread::kAutoStart),
+        device_client_(new TestDeviceClient()) {}
 
  protected:
   base::test::ScopedTaskEnvironment scoped_task_environment_;