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

Source/core/svg/SVGFEPointLightElement.h

Index: Source/core/svg/SVGFEPointLightElement.h
diff --git a/Source/core/svg/SVGFEPointLightElement.h b/Source/core/svg/SVGFEPointLightElement.h
index eda7c6d155fb8c9fbd7c908aef178ac9fbf9d4f5..0f5bfb58eabdad230270fdfa3a934bd711d690e2 100644
--- a/Source/core/svg/SVGFEPointLightElement.h
+++ b/Source/core/svg/SVGFEPointLightElement.h
@@ -29,6 +29,8 @@ class SVGFEPointLightElement : public SVGFELightElement {
 public:
     static PassRefPtr<SVGFEPointLightElement> create(const QualifiedName&, const Handle<Document>&);
 
+    virtual void accept(Visitor* visitor) const OVERRIDE { SVGFELightElement::accept(visitor); }
+
 private:
     SVGFEPointLightElement(const QualifiedName&, const Handle<Document>&);