Make a pen in eraser mode visible thru PointerEvent.buttons

third_party/WebKit/public/platform/WebPointerProperties.h

Index: third_party/WebKit/public/platform/WebPointerProperties.h
diff --git a/third_party/WebKit/public/platform/WebPointerProperties.h b/third_party/WebKit/public/platform/WebPointerProperties.h
index d1eb233b415ca30b73ad770a11a61f69394f3aac..8902dfba6ea6dc625d7f268249c39e7f64ab37b7 100644
--- a/third_party/WebKit/public/platform/WebPointerProperties.h
+++ b/third_party/WebKit/public/platform/WebPointerProperties.h
@@ -31,7 +31,20 @@ public:
         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 {