Moving input device hotplug event processing outside of ui/display

ui/events/touchscreen_device.h

 // 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.
 
-#ifndef UI_DISPLAY_TYPES_CHROMEOS_TOUCHSCREEN_DEVICE_H_
-#define UI_DISPLAY_TYPES_CHROMEOS_TOUCHSCREEN_DEVICE_H_
+#ifndef UI_EVENTS_TOUCHSCREEN_DEVICE_H_
+#define UI_EVENTS_TOUCHSCREEN_DEVICE_H_
 
-#include "ui/display/types/display_types_export.h"
+#include "ui/events/events_export.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace ui {
 
 // Represents a Touchscreen device state.
-struct DISPLAY_TYPES_EXPORT TouchscreenDevice {
-  static const int kInvalidId;
+struct EVENTS_EXPORT TouchscreenDevice {
+  static const int kInvalidId = 0;
 
   TouchscreenDevice(int id, const gfx::Size& size);
 
   // ID of the touch screen. This ID must uniquely identify the touch screen.
   int id;
 
   // Size of the touch screen area.
   gfx::Size size;
 };
 
 }  // namespace ui
 
-#endif  // UI_DISPLAY_TYPES_CHROMEOS_TOUCHSCREEN_DEVICE_H_
+#endif  // UI_EVENTS_TOUCHSCREEN_DEVICE_H_