evdev: Support device hotplug with udev

ui/events/ozone/evdev/scoped_udev.h

Index: ui/events/ozone/evdev/scoped_udev.h
diff --git a/ui/events/ozone/evdev/scoped_udev.h b/ui/events/ozone/evdev/scoped_udev.h
index c71950821c34bc221d997ec78bd8f1503fa8d48a..21063e3225d4c633055dfd9718757e5d90aab008 100644
--- a/ui/events/ozone/evdev/scoped_udev.h
+++ b/ui/events/ozone/evdev/scoped_udev.h
@@ -37,6 +37,14 @@ struct UdevEnumerateDeleter {
 typedef scoped_ptr<struct udev_enumerate, UdevEnumerateDeleter>
     scoped_udev_enumerate;
 
+// Scoped struct udev_monitor.
+struct UdevMonitorDeleter {
+  void operator()(struct udev_monitor* udev_monitor) {
+    udev_monitor_unref(udev_monitor);
+  }
+};
+typedef scoped_ptr<struct udev_monitor, UdevMonitorDeleter> scoped_udev_monitor;
+
 }  // namespace ui
 
 #endif  // UI_EVENTS_OZONE_EVDEV_SCOPED_UDEV_H_