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

Source/core/html/shadow/HTMLContentElement.h

Index: Source/core/html/shadow/HTMLContentElement.h
diff --git a/Source/core/html/shadow/HTMLContentElement.h b/Source/core/html/shadow/HTMLContentElement.h
index 437a9e30a480fb321c89efac187d505d3b7230e0..7611ae7e2f37641e371d7c05d3599a5b4244df93 100644
--- a/Source/core/html/shadow/HTMLContentElement.h
+++ b/Source/core/html/shadow/HTMLContentElement.h
@@ -54,11 +54,11 @@ public:
     virtual bool canAffectSelector() const OVERRIDE { return true; }
     virtual bool isSelectValid();
 
-    virtual void acceptHeapVisitor(Visitor*) const OVERRIDE;
-
 protected:
     HTMLContentElement(const QualifiedName&, Handle<Document>);
 
+    virtual void acceptHeapVisitor(Visitor*) const OVERRIDE;
+
 private:
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     void ensureSelectParsed();