Keep track of fixed positioning in accessibility tree.

ui/accessibility/ax_node.h

Index: ui/accessibility/ax_node.h
diff --git a/ui/accessibility/ax_node.h b/ui/accessibility/ax_node.h
index 6dd907f5a3f9e347c8a65aa8983a0cc2182c4932..bec061c72bd0a78b79bc4800dce9331bd447bd3d 100644
--- a/ui/accessibility/ax_node.h
+++ b/ui/accessibility/ax_node.h
@@ -49,7 +49,8 @@ class AX_EXPORT AXNode {
   // See ax_node_data.h for details.
   void SetLocation(int offset_container_id,
                    const gfx::RectF& location,
-                   gfx::Transform* transform);
+                   gfx::Transform* transform,
+                   bool is_fixed_positioned);
 
   // Set the index in parent, for example if siblings were inserted or deleted.
   void SetIndexInParent(int index_in_parent);