Clean up HID backend and API.

device/hid/hid_service_unittest.cc

Index: device/hid/hid_service_unittest.cc
diff --git a/device/hid/hid_service_unittest.cc b/device/hid/hid_service_unittest.cc
index 1fa1c0a9bd009b18452fc168ae7160090357968f..0b5043bd8644b6ce58ec839dd535ec0c8c923dcd 100644
--- a/device/hid/hid_service_unittest.cc
+++ b/device/hid/hid_service_unittest.cc
@@ -1,16 +1,11 @@
-// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// 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 <string>
 #include <vector>
 
-#include "base/bind.h"
-#include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
-#include "device/hid/hid_connection.h"
 #include "device/hid/hid_service.h"
-#include "net/base/io_buffer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace device {
@@ -22,11 +17,10 @@ TEST(HidServiceTest, Create) {
 
   std::vector<HidDeviceInfo> devices;
   service->GetDevices(&devices);
-
   for (std::vector<HidDeviceInfo>::iterator it = devices.begin();
       it != devices.end();
       ++it) {
-    ASSERT_TRUE(!it->device_id.empty());
+    ASSERT_TRUE(it->device_id != kInvalidHidDeviceId);
   }
 }