<fieldset> should be ignored in interactive validation

Source/core/html/HTMLFieldSetElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2010 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * 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
@@ skipping 58 matching lines @@
     for (unsigned i = 0; i < elements.size(); ++i) {
         if (elements[i]->isFormControlElement()) {
             HTMLFormControlElement* control = toHTMLFormControlElement(elements[i].get());
             if (!control->checkValidity(0, CheckValidityDispatchNoEvent))
                 return false;
         }
     }
     return true;
 }
 
+bool HTMLFieldSetElement::isSubmittableElement()
+{
+    return false;
+}
+
 void HTMLFieldSetElement::invalidateDisabledStateUnder(Element& base)
 {
     for (HTMLFormControlElement& element : Traversal<HTMLFormControlElement>::descendantsOf(base))
         element.ancestorDisabledStateWasChanged();
 }
 
 void HTMLFieldSetElement::disabledAttributeChanged()
 {
     // This element must be updated before the style of nodes in its subtree gets recalculated.
     HTMLFormControlElement::disabledAttributeChanged();
@@ skipping 56 matching lines @@
     }
 }
 
 const FormAssociatedElement::List& HTMLFieldSetElement::associatedElements() const
 {
     refreshElementsIfNeeded();
     return m_associatedElements;
 }
 
 } // namespace