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

third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp b/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
index 65461fc858675b32b3b0ed0e5a5575f6e5feca5a..b80f79cf0fa0ee4f3be98b053ac1f5182dcca54e 100644
--- a/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLFormControlElement.cpp
@@ -109,20 +109,19 @@ bool HTMLFormControlElement::formNoValidate() const {
 }
 
 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;
 }