Keep track of fixed positioning in accessibility tree.

third_party/WebKit/Source/modules/accessibility/AXMenuListOption.h

 /*
  * Copyright (C) 2010 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 50 matching lines @@
   bool IsEnabled() const override;
   bool IsVisible() const override;
   bool IsOffScreen() const override;
   bool IsSelected() const override;
   void SetSelected(bool) override;
   bool CanSetSelectedAttribute() const override;
   bool CanSetFocusAttribute() const override;
 
   void GetRelativeBounds(AXObject** out_container,
                          FloatRect& out_bounds_in_container,
-                         SkMatrix44& out_container_transform) const override;
+                         SkMatrix44& out_container_transform,
+                         bool& out_is_fixed_positioned) const override;
   String TextAlternative(bool recursive,
                          bool in_aria_labelled_by_traversal,
                          AXObjectSet& visited,
                          AXNameFrom&,
                          AXRelatedObjectVector*,
                          NameSources*) const override;
   bool ComputeAccessibilityIsIgnored(IgnoredReasons* = nullptr) const override;
   HTMLSelectElement* ParentSelectNode() const;
 
   Member<HTMLOptionElement> element_;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXMenuListOption, IsMenuListOption());
 
 }  // namespace blink
 
 #endif  // AXMenuListOption_h