Make a pen in eraser mode visible thru PointerEvent.buttons

third_party/WebKit/public/platform/WebPointerProperties.h

 // Copyright (c) 2015 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 WebPointerProperties_h
 #define WebPointerProperties_h
 
 #include <cstdint>
 #include <limits>
 
@@ skipping 13 matching lines @@
         , tiltY(0)
         , button(Button::NoButton)
         , pointerType(PointerType::Unknown)
     {
     }
 
     enum class Button {
         NoButton = -1,
         Left,
         Middle,
-        Right
+        Right,
+        X1,
+        X2,
+        Eraser
+    };
+
+    enum class Buttons : unsigned {
+        NoButton = 0,
+        Left = 1 << 0,
+        Right = 1 << 1,
+        Middle = 1 << 2,
+        X1 = 1 << 3,
+        X2 = 1 << 4,
+        Eraser = 1 << 5
     };
 
     enum class PointerType {
         Unknown,
         Mouse,
         Pen,
         Touch,
         LastEntry = Touch // Must be the last entry in the list
     };
 
     int id;
 
     // The valid range is [0,1], with NaN meaning pressure is not supported by
     // the input device.
     float force;
 
     // Tilt of a pen stylus from surface normal as plane angles in degrees,
     // Values lie in [-90,90]. A positive tiltX is to the right and a positive
     // tiltY is towards the user.
     int tiltX;
     int tiltY;
 
     Button button;
     PointerType pointerType;
 };
 
 } // namespace blink
 
 #endif