Scaling and offset fix for FELighting (software and skia paths)

Source/platform/graphics/filters/PointLightSource.h

 /*
  * Copyright (C) 2008 Alex Mathews <possessedpenguinbob@gmail.com>
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 16 matching lines @@
 
 namespace WebCore {
 
 class PLATFORM_EXPORT PointLightSource : public LightSource {
 public:
     static PassRefPtr<PointLightSource> create(const FloatPoint3D& position)
     {
         return adoptRef(new PointLightSource(position));
     }
 
+    virtual PassRefPtr<LightSource> create(const FloatPoint3D& scale, const FloatSize& offset) const OVERRIDE
+    {
+        FloatPoint3D position(m_position.x() * scale.x() - offset.width(), m_position.y() * scale.y() - offset.height(), m_position.z() * scale.z());
+        return adoptRef(new PointLightSource(position));
+    }
+
     const FloatPoint3D& position() const { return m_position; }
     virtual bool setX(float) OVERRIDE;
     virtual bool setY(float) OVERRIDE;
     virtual bool setZ(float) OVERRIDE;
 
-    virtual void initPaintingData(PaintingData&) OVERRIDE;
-    virtual void updatePaintingData(PaintingData&, int x, int y, float z) OVERRIDE;
+    virtual void initPaintingData(PaintingData&) const OVERRIDE;
+    virtual void updatePaintingData(PaintingData&, int x, int y, float z) const OVERRIDE;
 
     virtual TextStream& externalRepresentation(TextStream&) const OVERRIDE;
 
 private:
     PointLightSource(const FloatPoint3D& position)
         : LightSource(LS_POINT)
         , m_position(position)
     {
     }
 
     FloatPoint3D m_position;
 };
 
 } // namespace WebCore
 
 #endif // PointLightSource_h