FIELDSET element: Correct nested FIELDSET behavior for descendant |disabled| state.

third_party/WebKit/Source/core/html/HTMLFormControlElement.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, 2007 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 91 matching lines @@
 
 void HTMLFormControlElement::setFormMethod(const AtomicString& value) {
   setAttribute(formmethodAttr, value);
 }
 
 bool HTMLFormControlElement::formNoValidate() const {
   return fastHasAttribute(formnovalidateAttr);
 }
 
 void HTMLFormControlElement::updateAncestorDisabledState() const {
-  HTMLFieldSetElement* fieldSetAncestor = 0;
-  ContainerNode* legendAncestor = 0;
+  HTMLFieldSetElement* highestDisabledFieldSetAncestor = nullptr;
+  ContainerNode* highestLegendAncestor = nullptr;
   for (HTMLElement* ancestor = Traversal<HTMLElement>::firstAncestor(*this);
        ancestor; ancestor = Traversal<HTMLElement>::firstAncestor(*ancestor)) {
-    if (!legendAncestor && isHTMLLegendElement(*ancestor))
-      legendAncestor = ancestor;
-    if (isHTMLFieldSetElement(*ancestor)) {
-      fieldSetAncestor = toHTMLFieldSetElement(ancestor);
-      break;
-    }
+    if (isHTMLLegendElement(*ancestor))
+      highestLegendAncestor = ancestor;
+    if (isHTMLFieldSetElement(*ancestor) && ancestor->isDisabledFormControl())
+      highestDisabledFieldSetAncestor = toHTMLFieldSetElement(ancestor);
   }
   m_ancestorDisabledState =
-      (fieldSetAncestor && fieldSetAncestor->isDisabledFormControl() &&
-       !(legendAncestor && legendAncestor == fieldSetAncestor->legend()))
+      (highestDisabledFieldSetAncestor &&
+       !(highestLegendAncestor &&
+         highestLegendAncestor == highestDisabledFieldSetAncestor->legend()))
           ? AncestorDisabledStateDisabled
           : AncestorDisabledStateEnabled;
 }
 
 void HTMLFormControlElement::ancestorDisabledStateWasChanged() {
   m_ancestorDisabledState = AncestorDisabledStateUnknown;
   disabledAttributeChanged();
 }
 
 void HTMLFormControlElement::reset() {
@@ skipping 499 matching lines @@
     const Element& source) {
   HTMLElement::copyNonAttributePropertiesFromElement(source);
   setNeedsValidityCheck();
 }
 
 void HTMLFormControlElement::associateWith(HTMLFormElement* form) {
   associateByParser(form);
 };
 
 }  // namespace blink