Linux: Unify udev scopers.

device/udev_linux/udev.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 <libudev.h>
+
+#include "device/udev_linux/udev.h"
+
+namespace device {
+
+void UdevDeleter::operator()(udev* dev) const {
+  udev_unref(dev);
+}
+
+void UdevEnumerateDeleter::operator()(udev_enumerate* enumerate) const {
+  udev_enumerate_unref(enumerate);
+}
+
+void UdevDeviceDeleter::operator()(udev_device* device) const {
+  udev_device_unref(device);
+}
+
+void UdevMonitorDeleter::operator()(udev_monitor* monitor) const {
+  udev_monitor_unref(monitor);
+}
+
+}  // namespace device