Use the task scheduler in the new Windows USB backend

device/hid/hid_connection_unittest.cc

 // Copyright (c) 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 "device/hid/hid_connection.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/scoped_observer.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/test/test_io_thread.h"
 #include "device/hid/hid_service.h"
 #include "device/test/test_device_client.h"
 #include "device/test/usb_test_gadget.h"
 #include "device/usb/usb_device.h"
 #include "net/base/io_buffer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace device {
 
@@ skipping 113 matching lines @@
   bool result_;
   size_t size_;
   scoped_refptr<net::IOBuffer> buffer_;
   HidConnection::ReadCallback read_callback_;
   HidConnection::WriteCallback write_callback_;
 };
 
 }  // namespace
 
 class HidConnectionTest : public testing::Test {
+ public:
+  HidConnectionTest()
+      : scoped_task_environment_(
+            base::test::ScopedTaskEnvironment::MainThreadType::UI),
+        io_thread_(base::TestIOThread::kAutoStart) {}
+
  protected:
   void SetUp() override {
     if (!UsbTestGadget::IsTestEnabled()) return;
 
-    message_loop_.reset(new base::MessageLoopForUI());
-    io_thread_.reset(new base::TestIOThread(base::TestIOThread::kAutoStart));
-    device_client_.reset(new TestDeviceClient(io_thread_->task_runner()));
-
     service_ = DeviceClient::Get()->GetHidService();
     ASSERT_TRUE(service_);
 
-    test_gadget_ = UsbTestGadget::Claim(io_thread_->task_runner());
+    test_gadget_ = UsbTestGadget::Claim(io_thread_.task_runner());
     ASSERT_TRUE(test_gadget_);
     ASSERT_TRUE(test_gadget_->SetType(UsbTestGadget::HID_ECHO));
 
     DeviceCatcher device_catcher(service_,
                                  test_gadget_->GetDevice()->serial_number());
     device_id_ = device_catcher.WaitForDevice();
     ASSERT_NE(device_id_, kInvalidHidDeviceId);
   }
 
-  std::unique_ptr<base::MessageLoopForUI> message_loop_;
-  std::unique_ptr<base::TestIOThread> io_thread_;
-  std::unique_ptr<TestDeviceClient> device_client_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;

[mcasas, 2017/05/16 21:24:24]

Probably can be made const, and |io_thread_| too.

[Reilly Grant (use Gerrit), 2017/05/16 21:59:08]

These fields can be made const because we don't call any of their non-const
member functions but the idea of a const task environment or thread feels odd to
me.

[mcasas, 2017/05/16 23:19:48]

I like const fields because it tells me that they'll
be constructed or passed on constructor, and then 
essentially never mutated.  Eases the reader's load.

+  base::TestIOThread io_thread_;
+  TestDeviceClient device_client_;
   HidService* service_;
   std::unique_ptr<UsbTestGadget> test_gadget_;
   HidDeviceId device_id_;
 };
 
 TEST_F(HidConnectionTest, ReadWrite) {
   if (!UsbTestGadget::IsTestEnabled()) return;
 
   TestConnectCallback connect_callback;
   service_->Connect(device_id_, connect_callback.callback());
@@ skipping 19 matching lines @@
     ASSERT_EQ(0, read_callback.buffer()->data()[0]);
     for (unsigned char j = 1; j < kBufferSize; ++j) {
       ASSERT_EQ(i + j - 1, read_callback.buffer()->data()[j]);
     }
   }
 
   conn->Close();
 }
 
 }  // namespace device