Add WebPointerProperties type.

public/web/WebInputEvent.h

Index: public/web/WebInputEvent.h
diff --git a/public/web/WebInputEvent.h b/public/web/WebInputEvent.h
index b5d0a8bc6052b1f56fabe2537e52a02a86eb92b8..8bc850ac52c867f018ecffb86346023cac045aeb 100644
--- a/public/web/WebInputEvent.h
+++ b/public/web/WebInputEvent.h
@@ -34,6 +34,7 @@
 #include "../platform/WebCommon.h"
 #include "../platform/WebGestureDevice.h"
 #include "../platform/WebRect.h"
+#include "WebPointerProperties.h"
 #include "WebTouchPoint.h"
 
 #include <string.h>
@@ -300,16 +301,8 @@ public:
 
 // WebMouseEvent --------------------------------------------------------------
 
-class WebMouseEvent : public WebInputEvent {
+class WebMouseEvent : public WebInputEvent, public WebPointerProperties {
 public:
-    enum Button {
-        ButtonNone = -1,
-        ButtonLeft,
-        ButtonMiddle,
-        ButtonRight
-    };
-
-    Button button;
     int x;
     int y;
     int windowX;
@@ -322,7 +315,7 @@ public:
 
     WebMouseEvent()
         : WebInputEvent(sizeof(WebMouseEvent))
-        , button(ButtonNone)
+        , WebPointerProperties()
         , x(0)
         , y(0)
         , windowX(0)
@@ -338,7 +331,7 @@ public:
 protected:
     explicit WebMouseEvent(unsigned sizeParam)
         : WebInputEvent(sizeParam)
-        , button(ButtonNone)
+        , WebPointerProperties()
         , x(0)
         , y(0)
         , windowX(0)
@@ -522,6 +515,7 @@ public:
 
 // WebTouchEvent --------------------------------------------------------------
 
+// TODO(e_hakkinen): Replace with WebPointerEvent.

[Rick Byers, 2015/07/09 00:44:26]

nit: Reference crbug.com/508283

[USE eero AT chromium.org, 2015/07/14 23:44:13]

Done.

 class WebTouchEvent : public WebInputEvent {
 public:
     // Maximum number of simultaneous touches supported on