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

Source/core/svg/SVGFEFuncRElement.h

Index: Source/core/svg/SVGFEFuncRElement.h
diff --git a/Source/core/svg/SVGFEFuncRElement.h b/Source/core/svg/SVGFEFuncRElement.h
index bc85c59d871f29ebfb78da13a7ac5f30725bf750..4154ce1461a4676ea8060c4e37a51d218639d3e8 100644
--- a/Source/core/svg/SVGFEFuncRElement.h
+++ b/Source/core/svg/SVGFEFuncRElement.h
@@ -30,6 +30,8 @@ class SVGFEFuncRElement : public SVGComponentTransferFunctionElement {
 public:
     static PassRefPtr<SVGFEFuncRElement> create(const QualifiedName&, const Handle<Document>&);
 
+    virtual void accept(Visitor* visitor) const OVERRIDE { SVGComponentTransferFunctionElement::accept(visitor); }
+
 private:
     SVGFEFuncRElement(const QualifiedName&, const Handle<Document>&);
 };