<fieldset> should be ignored in interactive validation

Source/core/html/HTMLFormControlElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 89 matching lines @@
     virtual void setCustomValidity(const String&) override final;
     void findCustomValidationMessageTextDirection(const String& message, TextDirection &messageDir, String& subMessage, TextDirection& subMessageDir);
 
     bool isReadOnly() const { return m_isReadOnly; }
     bool isDisabledOrReadOnly() const { return isDisabledFormControl() || m_isReadOnly; }
 
     bool isAutofocusable() const;
 
     bool isAutofilled() const { return m_isAutofilled; }
     void setAutofilled(bool = true);
-
+    bool isSubmittableElement();
     static HTMLFormControlElement* enclosingFormControlElement(Node*);
 
     String nameForAutofill() const;
 
     virtual void setFocus(bool flag) override;
     virtual void copyNonAttributePropertiesFromElement(const Element&) override;
 
 #if !ENABLE(OILPAN)
     using Node::ref;
     using Node::deref;
@@ skipping 82 matching lines @@
 {
     return element.isFormControlElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLFormControlElement);
 DEFINE_TYPE_CASTS(HTMLFormControlElement, FormAssociatedElement, control, control->isFormControlElement(), control.isFormControlElement());
 
 } // namespace
 
 #endif