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

Source/core/html/ButtonInputType.h

Index: Source/core/html/ButtonInputType.h
diff --git a/Source/core/html/ButtonInputType.h b/Source/core/html/ButtonInputType.h
index 6ad4098a8e6db911f2ad4819e926cc29addb544b..b6cf120b89905cbb996ea206c271ee420b572791 100644
--- a/Source/core/html/ButtonInputType.h
+++ b/Source/core/html/ButtonInputType.h
@@ -37,10 +37,10 @@ namespace WebCore {
 
 class ButtonInputType : public BaseButtonInputType {
 public:
-    static PassOwnPtr<InputType> create(HTMLInputElement*);
+    static PassOwnPtr<InputType> create(Handle<HTMLInputElement>);
 
 private:
-    ButtonInputType(HTMLInputElement* element) : BaseButtonInputType(element) { }
+    ButtonInputType(const Handle<HTMLInputElement>&);
     virtual const AtomicString& formControlType() const OVERRIDE;
     virtual bool supportsValidation() const OVERRIDE;
     virtual bool isTextButton() const OVERRIDE;