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

Source/core/html/shadow/InsertionPoint.cpp

Index: Source/core/html/shadow/InsertionPoint.cpp
diff --git a/Source/core/html/shadow/InsertionPoint.cpp b/Source/core/html/shadow/InsertionPoint.cpp
index 3fa0426d25d988dd2888ca9c0aa055f0d65e05c4..201eb22e75a5b78b656c0ed35f8a853d66e640d3 100644
--- a/Source/core/html/shadow/InsertionPoint.cpp
+++ b/Source/core/html/shadow/InsertionPoint.cpp
@@ -253,4 +253,9 @@ void collectInsertionPointsWhereNodeIsDistributed(const Node* node, Vector<Inser
     }
 }
 
+void InsertionPoint::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLElement::acceptHeapVisitor(visitor);
+}
+
 } // namespace WebCore