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

Source/core/svg/graphics/filters/SVGFilter.cpp

Index: Source/core/svg/graphics/filters/SVGFilter.cpp
diff --git a/Source/core/svg/graphics/filters/SVGFilter.cpp b/Source/core/svg/graphics/filters/SVGFilter.cpp
index ff85c6aa82306963d8a25c8034fdbafaa068fb2d..f51424002729d4c73a76baea0829159c34d9b7b7 100644
--- a/Source/core/svg/graphics/filters/SVGFilter.cpp
+++ b/Source/core/svg/graphics/filters/SVGFilter.cpp
@@ -30,24 +30,24 @@ SVGFilter::SVGFilter(const AffineTransform& absoluteTransform, const FloatRect&
     : Filter(absoluteTransform)
     , m_absoluteSourceDrawingRegion(absoluteSourceDrawingRegion)
     , m_targetBoundingBox(targetBoundingBox)
-    , m_filterRegion(filterRegion)
     , m_effectBBoxMode(effectBBoxMode)
 {
-    m_absoluteFilterRegion = absoluteTransform.mapRect(filterRegion);
+    setFilterRegion(filterRegion);
+    setAbsoluteFilterRegion(absoluteTransform.mapRect(filterRegion));
 }
 
 float SVGFilter::applyHorizontalScale(float value) const
 {
     if (m_effectBBoxMode)
         value *= m_targetBoundingBox.width();
-    return Filter::applyHorizontalScale(value) * m_absoluteFilterRegion.width() / m_filterRegion.width();
+    return Filter::applyHorizontalScale(value) * absoluteFilterRegion().width() / filterRegion().width();
 }
 
 float SVGFilter::applyVerticalScale(float value) const
 {
     if (m_effectBBoxMode)
         value *= m_targetBoundingBox.height();
-    return Filter::applyVerticalScale(value) * m_absoluteFilterRegion.height() / m_filterRegion.height();
+    return Filter::applyVerticalScale(value) * absoluteFilterRegion().height() / filterRegion().height();
 }
 
 PassRefPtr<SVGFilter> SVGFilter::create(const AffineTransform& absoluteTransform, const FloatRect& absoluteSourceDrawingRegion, const FloatRect& targetBoundingBox, const FloatRect& filterRegion, bool effectBBoxMode)