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

Source/core/html/HTMLTextAreaElement.h

Index: Source/core/html/HTMLTextAreaElement.h
diff --git a/Source/core/html/HTMLTextAreaElement.h b/Source/core/html/HTMLTextAreaElement.h
index f49e15d1ba971dbf5677a840781e410677cf2359..8d1b7f31411a0dc532d2e95f7b6fd6ef5802e555 100644
--- a/Source/core/html/HTMLTextAreaElement.h
+++ b/Source/core/html/HTMLTextAreaElement.h
@@ -33,7 +33,7 @@ class VisibleSelection;
 
 class HTMLTextAreaElement : public HTMLTextFormControlElement {
 public:
-    static PassRefPtr<HTMLTextAreaElement> create(const QualifiedName&, Document*, HTMLFormElement*);
+    static Result<HTMLTextAreaElement> create(const QualifiedName&, Document*, HTMLFormElement*);
 
     int cols() const { return m_cols; }
     int rows() const { return m_rows; }
@@ -60,6 +60,8 @@ public:
     void setCols(int);
     void setRows(int);
 
+    virtual void acceptHeapVisitor(Visitor*) const OVERRIDE;
+
 private:
     HTMLTextAreaElement(const QualifiedName&, Document*, HTMLFormElement*);