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

Source/core/svg/SVGFEFuncAElement.h

Index: Source/core/svg/SVGFEFuncAElement.h
diff --git a/Source/core/svg/SVGFEFuncAElement.h b/Source/core/svg/SVGFEFuncAElement.h
index 30d6a9dcb0aab225ab72de95e554dd00a82d33f3..84bba183b9230ecd61ae9fdf24dc3d14ade3e057 100644
--- a/Source/core/svg/SVGFEFuncAElement.h
+++ b/Source/core/svg/SVGFEFuncAElement.h
@@ -30,6 +30,8 @@ class SVGFEFuncAElement : public SVGComponentTransferFunctionElement {
 public:
     static PassRefPtr<SVGFEFuncAElement> create(const QualifiedName&, const Handle<Document>&);
 
+    virtual void accept(Visitor* visitor) const OVERRIDE { SVGComponentTransferFunctionElement::accept(visitor); }
+
 private:
     SVGFEFuncAElement(const QualifiedName&, const Handle<Document>&);
 };