WheelEvent's deltaX/deltaY sign is wrong

Source/core/dom/WheelEvent.h

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 63 matching lines @@
     }
 
     void initWheelEvent(int rawDeltaX, int rawDeltaY, PassRefPtr<AbstractView>,
         int screenX, int screenY, int pageX, int pageY,
         bool ctrlKey, bool altKey, bool shiftKey, bool metaKey);
 
     void initWebKitWheelEvent(int rawDeltaX, int rawDeltaY, PassRefPtr<AbstractView>,
         int screenX, int screenY, int pageX, int pageY,
         bool ctrlKey, bool altKey, bool shiftKey, bool metaKey);
 
-    double deltaX() const { return m_deltaX; }
-    double deltaY() const { return m_deltaY; }
+    double deltaX() const { return m_deltaX; } // Positive when scrolling right.
+    double deltaY() const { return m_deltaY; } // Positive when scrolling down.
     double deltaZ() const { return m_deltaZ; }
-    int wheelDelta() const { return m_deltaY ? m_deltaY : m_deltaX; } // Deprecated.
-    int wheelDeltaX() const { return m_deltaX; } // Deprecated.
-    int wheelDeltaY() const { return m_deltaY; } // Deprecated.
+    int wheelDelta() const { return wheelDeltaY() ? wheelDeltaY() : wheelDeltaX(); } // Deprecated.
+    int wheelDeltaX() const { return -m_deltaX; } // Deprecated, negative when scrolling right.
+    int wheelDeltaY() const { return -m_deltaY; } // Deprecated, negative when scrolling down.
     int rawDeltaX() const { return m_rawDelta.x(); }
     int rawDeltaY() const { return m_rawDelta.y(); }
     unsigned deltaMode() const { return m_deltaMode; }
 
     bool webkitDirectionInvertedFromDevice() const { return m_directionInvertedFromDevice; }
 
     virtual const AtomicString& interfaceName() const;
     virtual bool isMouseEvent() const;
 
 private:
@@ skipping 16 matching lines @@
     static PassRefPtr<WheelEventDispatchMediator> create(const PlatformWheelEvent&, PassRefPtr<AbstractView>);
 private:
     WheelEventDispatchMediator(const PlatformWheelEvent&, PassRefPtr<AbstractView>);
     WheelEvent* event() const;
     virtual bool dispatchEvent(EventDispatcher*) const OVERRIDE;
 };
 
 } // namespace WebCore
 
 #endif // WheelEvent_h