[oilpan] The Node hierarchy should have correct accept method chains

Source/core/html/HTMLSourceElement.cpp

Index: Source/core/html/HTMLSourceElement.cpp
diff --git a/Source/core/html/HTMLSourceElement.cpp b/Source/core/html/HTMLSourceElement.cpp
index f8b0b72da8d8db779a700487aeb88fb3ac889590..d003a42a02f8e5730f3443dae1df467162d8b9c5 100644
--- a/Source/core/html/HTMLSourceElement.cpp
+++ b/Source/core/html/HTMLSourceElement.cpp
@@ -123,4 +123,9 @@ bool HTMLSourceElement::isURLAttribute(const Attribute& attribute) const
     return attribute.name() == srcAttr || HTMLElement::isURLAttribute(attribute);
 }
 
+void HTMLSourceElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLElement::acceptHeapVisitor(visitor);
+}
+
 }