[oilpan] Completely move HTMLFormControlElement's hierarchy to the managed heap

Source/core/html/HTMLTextAreaElement.cpp

Index: Source/core/html/HTMLTextAreaElement.cpp
diff --git a/Source/core/html/HTMLTextAreaElement.cpp b/Source/core/html/HTMLTextAreaElement.cpp
index 53ec84bab105ef2055935ce7a96196a3c1b5b2aa..0b4af172e455ed3eab71a8bacbe431c9e61037a7 100644
--- a/Source/core/html/HTMLTextAreaElement.cpp
+++ b/Source/core/html/HTMLTextAreaElement.cpp
@@ -100,11 +100,11 @@ HTMLTextAreaElement::HTMLTextAreaElement(const QualifiedName& tagName, Document*
     ScriptWrappable::init(this);
 }
 
-PassRefPtr<HTMLTextAreaElement> HTMLTextAreaElement::create(const QualifiedName& tagName, Document* document, HTMLFormElement* form)
+Result<HTMLTextAreaElement> HTMLTextAreaElement::create(const QualifiedName& tagName, Document* document, HTMLFormElement* form)
 {
-    RefPtr<HTMLTextAreaElement> textArea = adoptRef(new HTMLTextAreaElement(tagName, document, form));
+    Handle<HTMLTextAreaElement> textArea = adoptNode(new HTMLTextAreaElement(tagName, document, form));
     textArea->ensureUserAgentShadowRoot();
-    return textArea.release();
+    return textArea;
 }
 
 void HTMLTextAreaElement::didAddUserAgentShadowRoot(ShadowRoot* root)
@@ -561,4 +561,9 @@ void HTMLTextAreaElement::updatePlaceholderText()
     fixPlaceholderRenderer(m_placeholder, innerTextElement());
 }
 
+void HTMLTextAreaElement::acceptHeapVisitor(Visitor* visitor) const
+{
+    HTMLTextFormControlElement::acceptHeapVisitor(visitor);
+}
+
 }