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

Source/core/svg/SVGAnimateTransformElement.h

Index: Source/core/svg/SVGAnimateTransformElement.h
diff --git a/Source/core/svg/SVGAnimateTransformElement.h b/Source/core/svg/SVGAnimateTransformElement.h
index 63ad9282124a914972d106822d22ae5156f4a202..9117ecaeb1512122d1d4f6c984ed893d6efbb691 100644
--- a/Source/core/svg/SVGAnimateTransformElement.h
+++ b/Source/core/svg/SVGAnimateTransformElement.h
@@ -37,6 +37,8 @@ public:
 
     SVGTransform::SVGTransformType transformType() const { return m_type; }
 
+    virtual void accept(Visitor* visitor) const OVERRIDE { SVGAnimateElement::accept(visitor); }
+
 private:
     SVGAnimateTransformElement(const QualifiedName&, const Handle<Document>&);