Refactor Udev device support in Ozone and add a DRM hotplug monitor

ui/events/events.gyp

Index: ui/events/events.gyp
diff --git a/ui/events/events.gyp b/ui/events/events.gyp
index cb796e55a59a8f9314d32efd9932765b3b1a799d..fed04fb1b81e3dd85bdc03653059c9880df195e7 100644
--- a/ui/events/events.gyp
+++ b/ui/events/events.gyp
@@ -118,6 +118,16 @@
         'gestures/gesture_types.h',
         'gestures/velocity_calculator.cc',
         'gestures/velocity_calculator.h',
+        'ozone/device/device_event.cc',
+        'ozone/device/device_event.h',
+        'ozone/device/device_event_observer.h',
+        'ozone/device/device_manager.cc',
+        'ozone/device/device_manager.h',
+        'ozone/device/device_manager_manual.cc',
+        'ozone/device/device_manager_manual.h',
+        'ozone/device/udev/device_manager_udev.cc',
+        'ozone/device/udev/device_manager_udev.h',
+        'ozone/device/udev/scoped_udev.h',
         'ozone/evdev/libgestures_glue/event_reader_libevdev_cros.cc',
         'ozone/evdev/libgestures_glue/event_reader_libevdev_cros.h',
         'ozone/evdev/libgestures_glue/gesture_interpreter_libevdev_cros.cc',
@@ -126,10 +136,6 @@
         'ozone/evdev/libgestures_glue/gesture_logging.h',
         'ozone/evdev/libgestures_glue/gesture_timer_provider.cc',
         'ozone/evdev/libgestures_glue/gesture_timer_provider.h',
-        'ozone/evdev/device_manager_evdev.cc',
-        'ozone/evdev/device_manager_evdev.h',
-        'ozone/evdev/device_manager_udev.cc',
-        'ozone/evdev/device_manager_udev.h',
         'ozone/evdev/event_converter_evdev.cc',
         'ozone/evdev/event_converter_evdev.h',
         'ozone/evdev/event_device_info.cc',
@@ -224,9 +230,8 @@
           ],
         }],
         ['use_udev==0', {
-          'sources!': [
-            'ozone/evdev/device_manager_udev.cc',
-            'ozone/evdev/device_manager_udev.h',
+          'sources/': [
+            ['exclude', '_udev\\.(h|cc)$'],
           ],
         }],
       ],