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

Source/core/dom/TemplateContentDocumentFragment.h

Index: Source/core/dom/TemplateContentDocumentFragment.h
diff --git a/Source/core/dom/TemplateContentDocumentFragment.h b/Source/core/dom/TemplateContentDocumentFragment.h
index 8f43963620e2308ae43689f177c9d34c2175da5d..695d26dbc51e178df1fe64bef0656a3972bd53cf 100644
--- a/Source/core/dom/TemplateContentDocumentFragment.h
+++ b/Source/core/dom/TemplateContentDocumentFragment.h
@@ -38,7 +38,13 @@ public:
         return adoptRef(new TemplateContentDocumentFragment(document, host));
     }
 
-    const Element* host() const { return m_host; }
+    const Element* host() const { return Handle<const Element>(m_host).raw(); }
+
+    virtual void acceptHeapVisitor(Visitor* visitor) const OVERRIDE
+    {
+        visitor->visit(m_host);
+        DocumentFragment::acceptHeapVisitor(visitor);
+    }
 
 private:
     TemplateContentDocumentFragment(Handle<Document> document, const Element* host)
@@ -49,7 +55,7 @@ private:
 
     virtual bool isTemplateContent() const OVERRIDE { return true; }
 
-    const Element* m_host;
+    Member<const Element> m_host;
 };
 
 } // namespace WebCore