Create movementX/Y on MouseEvent

Source/core/events/MouseRelatedEvent.h

Index: Source/core/events/MouseRelatedEvent.h
diff --git a/Source/core/events/MouseRelatedEvent.h b/Source/core/events/MouseRelatedEvent.h
index 6ce689cd1bdf3c1cee95c0d1bc22b9aebae1ceef..2dd28ca5b599d90ee7aeeab861633dc34f5f262b 100644
--- a/Source/core/events/MouseRelatedEvent.h
+++ b/Source/core/events/MouseRelatedEvent.h
@@ -39,8 +39,8 @@ namespace WebCore {
         const IntPoint& screenLocation() const { return m_screenLocation; }
         int clientX() const { return m_clientLocation.x(); }
         int clientY() const { return m_clientLocation.y(); }
-        int webkitMovementX() const { return m_movementDelta.x(); }
-        int webkitMovementY() const { return m_movementDelta.y(); }
+        int movementX() const { return m_movementDelta.x(); }
+        int movementY() const { return m_movementDelta.y(); }
         const LayoutPoint& clientLocation() const { return m_clientLocation; }
         virtual int layerX() OVERRIDE FINAL;
         virtual int layerY() OVERRIDE FINAL;