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

Source/core/html/HTMLTemplateElement.cpp

Index: Source/core/html/HTMLTemplateElement.cpp
diff --git a/Source/core/html/HTMLTemplateElement.cpp b/Source/core/html/HTMLTemplateElement.cpp
index cec6015cc5dee720314fa3c9d90558fb6f79b717..907fc91382f7ef8243cf470c65d398d0a66a15a5 100644
--- a/Source/core/html/HTMLTemplateElement.cpp
+++ b/Source/core/html/HTMLTemplateElement.cpp
@@ -59,10 +59,11 @@ PassRefPtr<HTMLTemplateElement> HTMLTemplateElement::create(const QualifiedName&
 
 DocumentFragment* HTMLTemplateElement::content() const
 {
+    // FIXME(oilpan): Handlify TemplateContentDocumentFragment.
     if (!m_content)
-        m_content = TemplateContentDocumentFragment::create(document()->ensureTemplateDocument(), this);
+        m_content = adoptRawResult(TemplateContentDocumentFragment::create(document()->ensureTemplateDocument(), this).get());
 
-    return m_content.get();
+    return Handle<DocumentFragment>(m_content).raw();
 }
 
 PassRefPtr<Node> HTMLTemplateElement::cloneNode(bool deep)
@@ -81,7 +82,7 @@ void HTMLTemplateElement::didMoveToNewDocument(Handle<Document> oldDocument)
     HTMLElement::didMoveToNewDocument(oldDocument);
     if (!m_content)
         return;
-    document()->ensureTemplateDocument()->adoptIfNeeded(m_content.get());
+    document()->ensureTemplateDocument()->adoptIfNeeded(Handle<DocumentFragment>(m_content).raw());
 }
 
 #ifndef NDEBUG
@@ -92,4 +93,10 @@ const HTMLTemplateElement* toHTMLTemplateElement(const Node* node)
 }
 #endif
 
+void HTMLTemplateElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    visitor->visit(m_content);
+    HTMLElement::acceptHeapVisitor(visitor);
+}
+
 } // namespace WebCore