Implement filter primitive subregion for reference CSS filters. This required refactoring determin…

Source/core/rendering/FilterEffectRenderer.h

Index: Source/core/rendering/FilterEffectRenderer.h
diff --git a/Source/core/rendering/FilterEffectRenderer.h b/Source/core/rendering/FilterEffectRenderer.h
index 89bfdee33a5f5f46ed9e583dc9e2c41d0dae79a4..dd3149fb29820939c3370ed9a32c5a79292d0900 100644
--- a/Source/core/rendering/FilterEffectRenderer.h
+++ b/Source/core/rendering/FilterEffectRenderer.h
@@ -88,14 +88,15 @@ public:
     virtual void setSourceImageRect(const FloatRect& sourceImageRect)
     { 
         m_sourceDrawingRegion = sourceImageRect;
-        setMaxEffectRects(sourceImageRect);
         setFilterRegion(sourceImageRect);
+        lastEffect()->determineFilterPrimitiveSubregion();
         m_graphicsBufferAttached = false;
     }
     virtual FloatRect sourceImageRect() const { return m_sourceDrawingRegion; }
 
     virtual void setFilterRegion(const FloatRect& filterRegion) { m_filterRegion = filterRegion; }
     virtual FloatRect filterRegion() const { return m_filterRegion; }
+    virtual FloatRect filterRegionInUserSpace() const { return m_filterRegion; }
 
     GraphicsContext* inputContext();
     ImageBuffer* output() const { return lastEffect()->asImageBuffer(); }
@@ -114,13 +115,6 @@ public:
 
     bool hasCustomShaderFilter() const { return m_hasCustomShaderFilter; }
 private:
-    void setMaxEffectRects(const FloatRect& effectRect)
-    {
-        for (size_t i = 0; i < m_effects.size(); ++i) {
-            RefPtr<FilterEffect> effect = m_effects.at(i);
-            effect->setMaxEffectRect(effectRect);
-        }
-    }
     PassRefPtr<FilterEffect> lastEffect() const
     {
         if (m_effects.size() > 0)