Keep track of fixed positioning in accessibility tree.

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

 /*
  * Copyright (C) 2012, 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:
  *
  * 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
@@ skipping 169 matching lines @@
   String Description(AXNameFrom,
                      AXDescriptionFrom&,
                      DescriptionSources*,
                      AXRelatedObjectVector*) const override;
   String Placeholder(AXNameFrom) const override;
   bool NameFromLabelElement() const override;
 
   // Location
   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;
 
   // High-level accessibility tree access.
   AXObject* ComputeParent() const override;
   AXObject* ComputeParentIfExists() const override;
 
   // Low-level accessibility tree exploration.
   AXObject* RawFirstChild() const override;
   AXObject* RawNextSibling() const override;
   void AddChildren() override;
   bool CanHaveChildren() const override;
@@ skipping 38 matching lines @@
                                NameSources*,
                                bool* found_text_alternative) const;
   float StepValueForRange() const;
   bool IsDescendantOfElementType(HashSet<QualifiedName>& tag_names) const;
   String PlaceholderFromNativeAttribute() const;
 };
 
 }  // namespace blink
 
 #endif  // AXNodeObject_h