Check whether aria-expanded attribute is defined

public/web/WebAXEnums.h

Index: public/web/WebAXEnums.h
diff --git a/public/web/WebAXEnums.h b/public/web/WebAXEnums.h
index be747f560947bc1e9f72d04720b0502a8440c113..35afcb3a42649599d63a81ad7e17280e8d77b336 100644
--- a/public/web/WebAXEnums.h
+++ b/public/web/WebAXEnums.h
@@ -203,7 +203,6 @@ enum WebAXRole {
 enum WebAXState {
     WebAXStateBusy,
     WebAXStateChecked,
-    WebAXStateCollapsed,
     WebAXStateEnabled,
     WebAXStateExpanded,
     WebAXStateFocusable,
@@ -233,6 +232,15 @@ enum WebAXTextDirection {
     WebAXTextDirectionBT
 };
 
+// Expanded State.
+// These values must match blink::AccessibilityExpanded values.
+// Enforced in AssertMatchingEnums.cpp.
+enum WebAXExpanded {
+    WebAXExpandedUndefined = 0,
+    WebAXExpandedCollapsed,
+    WebAXExpandedExpanded
+};
+
 } // namespace blink
 
 #endif