Implement :valid and :invalid pseudoclass for <fieldset>

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 139 matching lines @@
     virtual void refFormAssociatedElement() override final { ref(); }
     virtual void derefFormAssociatedElement() override final { deref(); }
 #endif
 
     virtual bool isFormControlElement() const override final { return true; }
     virtual bool alwaysCreateUserAgentShadowRoot() const override { return true; }
 
     virtual short tabIndex() const override final;
 
     virtual bool isDefaultButtonForForm() const override final;
-    virtual bool isValidElement() override final;
-    virtual bool matchesValidityPseudoClasses() const override final;
+    virtual bool isValidElement() override;
+    virtual bool matchesValidityPseudoClasses() const override;
     void updateAncestorDisabledState() const;
 
     bool isValidationMessageVisible() const;
     ValidationMessageClient* validationMessageClient() const;
 
     // Requests validity recalc for the form owner, if one exists.
     void formOwnerSetNeedsValidityCheck();
+    // Requests validity recalc for all ancestor fieldsets, if exist.
+    void fieldSetAncestorsSetNeedsValidityCheck(Node*);
 
     bool m_disabled : 1;
     bool m_isAutofilled : 1;
     bool m_isReadOnly : 1;
     bool m_isRequired : 1;
     bool m_hasValidationMessage : 1;
 
     enum AncestorDisabledState { AncestorDisabledStateUnknown, AncestorDisabledStateEnabled, AncestorDisabledStateDisabled };
     mutable AncestorDisabledState m_ancestorDisabledState;
     enum DataListAncestorState { Unknown, InsideDataList, NotInsideDataList };
@@ skipping 17 matching lines @@
 {
     return element.isFormControlElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLFormControlElement);
 DEFINE_TYPE_CASTS(HTMLFormControlElement, FormAssociatedElement, control, control->isFormControlElement(), control.isFormControlElement());
 
 } // namespace
 
 #endif