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

Source/core/html/shadow/ClearButtonElement.cpp

Index: Source/core/html/shadow/ClearButtonElement.cpp
diff --git a/Source/core/html/shadow/ClearButtonElement.cpp b/Source/core/html/shadow/ClearButtonElement.cpp
index f69ccb10f56315eb939f92f6c721592b12c2c53b..79740db8ccf2442091276f18d02e7f3f887e28e4 100644
--- a/Source/core/html/shadow/ClearButtonElement.cpp
+++ b/Source/core/html/shadow/ClearButtonElement.cpp
@@ -109,4 +109,9 @@ void ClearButtonElement::defaultEventHandler(Event* event)
         HTMLDivElement::defaultEventHandler(event);
 }
 
+void ClearButtonElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLDivElement::acceptHeapVisitor(visitor);
+}
+
 }