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

Source/core/platform/graphics/filters/FEMorphology.cpp

Index: Source/core/platform/graphics/filters/FEMorphology.cpp
diff --git a/Source/core/platform/graphics/filters/FEMorphology.cpp b/Source/core/platform/graphics/filters/FEMorphology.cpp
index 1bc31aecc91fb89422b173bf857638c58eccb022..9d514fb1174dca24ea556ace51d26329c30c6005 100644
--- a/Source/core/platform/graphics/filters/FEMorphology.cpp
+++ b/Source/core/platform/graphics/filters/FEMorphology.cpp
@@ -89,10 +89,7 @@ float FEMorphology::radiusY() const
 
 void FEMorphology::determineAbsolutePaintRect()
 {
-    FloatRect paintRect = inputEffect(0)->absolutePaintRect();
-    Filter* filter = this->filter();
-    paintRect.inflateX(filter->applyHorizontalScale(m_radiusX));
-    paintRect.inflateY(filter->applyVerticalScale(m_radiusY));
+    FloatRect paintRect = mapRect(inputEffect(0)->absolutePaintRect());
     if (clipsToBounds())
         paintRect.intersect(maxEffectRect());
     else
@@ -100,6 +97,14 @@ void FEMorphology::determineAbsolutePaintRect()
     setAbsolutePaintRect(enclosingIntRect(paintRect));
 }
 
+FloatRect FEMorphology::mapRect(const FloatRect& rect, bool)
+{
+    FloatRect result = rect;
+    result.inflateX(filter()->applyHorizontalScale(m_radiusX));
+    result.inflateY(filter()->applyVerticalScale(m_radiusY));
+    return result;
+}
+
 bool FEMorphology::setRadiusY(float radiusY)
 {
     if (m_radiusY == radiusY)