Add POINTER_TYPE_ERASER to EventPointerType

ui/events/event_constants.h

 // Copyright (c) 2012 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_EVENTS_EVENT_CONSTANTS_H_
 #define UI_EVENTS_EVENT_CONSTANTS_H_
 
 namespace ui {
 
 // Event types. (prefixed because of a conflict with windows headers)
@@ skipping 155 matching lines @@
 enum EventDeviceId {
   ED_UNKNOWN_DEVICE = -1
 };
 
 // Pointing device type.
 enum class EventPointerType : int {
   POINTER_TYPE_UNKNOWN = 0,
   POINTER_TYPE_MOUSE,
   POINTER_TYPE_PEN,
   POINTER_TYPE_TOUCH,
+  POINTER_TYPE_ERASER,
 };
 
 // Device type for gesture events.
 enum class GestureDeviceType : int {
   DEVICE_UNKNOWN = 0,
   DEVICE_TOUCHPAD,
   DEVICE_TOUCHSCREEN,
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_CONSTANTS_H_