Refactor m_absoluteTransform out of SVGFilter and into base class.

Source/core/platform/graphics/filters/Filter.h

 /*
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>

[Stephen Chennney, 2013/05/01 18:34:18]

Let's finally add ourselves to the copyright.

  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
@@ skipping 11 matching lines @@
 #include "core/platform/graphics/FloatSize.h"
 #include "core/platform/graphics/ImageBuffer.h"
 #include <wtf/RefCounted.h>
 
 namespace WebCore {
 
 class FilterEffect;
 
 class Filter : public RefCounted<Filter> {
 public:
-    Filter() : m_renderingMode(Unaccelerated) { }
+    Filter(const AffineTransform& absoluteTransform) : m_absoluteTransform(absoluteTransform), m_renderingMode(Unaccelerated) { }
     virtual ~Filter() { }
 
     void setSourceImage(PassOwnPtr<ImageBuffer> sourceImage) { m_sourceImage = sourceImage; }
     ImageBuffer* sourceImage() { return m_sourceImage.get(); }
 
     FloatSize filterResolution() const { return m_filterResolution; }
     void setFilterResolution(const FloatSize& filterResolution) { m_filterResolution = filterResolution; }
 
+    const AffineTransform& absoluteTransform() const { return m_absoluteTransform; }
+    FloatPoint mapAbsolutePointToLocalPoint(const FloatPoint& point) const { return m_absoluteTransform.inverse().mapPoint(point); }
+
     RenderingMode renderingMode() const { return m_renderingMode; }
     void setRenderingMode(RenderingMode renderingMode) { m_renderingMode = renderingMode; }
 
     virtual float applyHorizontalScale(float value) const { return value * m_filterResolution.width(); }
     virtual float applyVerticalScale(float value) const { return value * m_filterResolution.height(); }
     
     virtual FloatRect sourceImageRect() const = 0;
     virtual FloatRect filterRegion() const = 0;
     
-    virtual FloatPoint mapAbsolutePointToLocalPoint(const FloatPoint&) const { return FloatPoint(); }
 
 private:
     OwnPtr<ImageBuffer> m_sourceImage;
     FloatSize m_filterResolution;
     RenderingMode m_renderingMode;
+    AffineTransform m_absoluteTransform;
 };
 
 } // namespace WebCore
 
 #endif // Filter_h