[oilpan] Implement accept methods to trace the class hierarchy of SVGElement and all sub-classes.

Source/core/svg/SVGFEDiffuseLightingElement.h

Index: Source/core/svg/SVGFEDiffuseLightingElement.h
diff --git a/Source/core/svg/SVGFEDiffuseLightingElement.h b/Source/core/svg/SVGFEDiffuseLightingElement.h
index 85bbd7b6f1f30aae4fd3fa651411a614e9a759ce..f418f2221d9fb543184497af9973d51a720306e2 100644
--- a/Source/core/svg/SVGFEDiffuseLightingElement.h
+++ b/Source/core/svg/SVGFEDiffuseLightingElement.h
@@ -36,6 +36,8 @@ public:
     static PassRefPtr<SVGFEDiffuseLightingElement> create(const QualifiedName&, const Handle<Document>&);
     void lightElementAttributeChanged(const SVGFELightElement*, const QualifiedName&);
 
+    virtual void accept(Visitor* visitor) const OVERRIDE { SVGFilterPrimitiveStandardAttributes::accept(visitor); }
+
 private:
     SVGFEDiffuseLightingElement(const QualifiedName&, const Handle<Document>&);