Check whether aria-expanded attribute is defined

public/web/WebAXEnums.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 185 matching lines @@
     WebAXRoleUserInterfaceTooltip,
     WebAXRoleValueIndicator,
     WebAXRoleWebArea,
     WebAXRoleWindow,
 };
 
 // Accessibility states, used as a bitmask.
 enum WebAXState {
     WebAXStateBusy,
     WebAXStateChecked,
-    WebAXStateCollapsed,
     WebAXStateEnabled,
     WebAXStateExpanded,
     WebAXStateFocusable,
     WebAXStateFocused,
     WebAXStateHaspopup,
     WebAXStateHovered,
     WebAXStateIndeterminate,
     WebAXStateInvisible,
     WebAXStateLinked,
     WebAXStateMultiselectable,
     WebAXStateOffscreen,
     WebAXStatePressed,
     WebAXStateProtected,
     WebAXStateReadonly,
     WebAXStateRequired,
     WebAXStateSelectable,
     WebAXStateSelected,
     WebAXStateVertical,
     WebAXStateVisited,
 };
 
 // Text direction, only used for role=WebAXRoleInlineTextBox.
 enum WebAXTextDirection {
     WebAXTextDirectionLR,
     WebAXTextDirectionRL,
     WebAXTextDirectionTB,
     WebAXTextDirectionBT
 };
 
+// Expanded State.
+// These values must match blink::AccessibilityExpanded values.
+// Enforced in AssertMatchingEnums.cpp.
+enum WebAXExpanded {
+    WebAXExpandedUndefined = 0,
+    WebAXExpandedCollapsed,
+    WebAXExpandedExpanded
+};
+
 } // namespace blink
 
 #endif