Use isSVG*Element() helpers more in SVG code (Part 3)

Source/core/rendering/svg/RenderSVGResourceFilter.cpp

Index: Source/core/rendering/svg/RenderSVGResourceFilter.cpp
diff --git a/Source/core/rendering/svg/RenderSVGResourceFilter.cpp b/Source/core/rendering/svg/RenderSVGResourceFilter.cpp
index 0f5724b126d4cf89c332cc421664c98a45acef87..f62c6534ad69d6f9f4c4631cf661ddcfe293f781 100644
--- a/Source/core/rendering/svg/RenderSVGResourceFilter.cpp
+++ b/Source/core/rendering/svg/RenderSVGResourceFilter.cpp
@@ -83,11 +83,7 @@ PassRefPtr<SVGFilterBuilder> RenderSVGResourceFilter::buildPrimitives(SVGFilter*
 
     // Add effects to the builder
     RefPtr<SVGFilterBuilder> builder = SVGFilterBuilder::create(SourceGraphic::create(filter), SourceAlpha::create(filter));
-    for (Element* child = ElementTraversal::firstWithin(*filterElement); child; child = ElementTraversal::nextSibling(*child)) {
-        if (!child->isSVGElement())
-            continue;
-
-        SVGElement* element = toSVGElement(child);
+    for (SVGElement* element = Traversal<SVGElement>::firstChild(*filterElement); element; element = Traversal<SVGElement>::nextSibling(*element)) {
         if (!element->isFilterEffect() || !element->renderer())
             continue;