Added the aria-sort state to the accessibility tree.

ui/accessibility/ax_enums.idl

Index: ui/accessibility/ax_enums.idl
diff --git a/ui/accessibility/ax_enums.idl b/ui/accessibility/ax_enums.idl
index 91caaf3f38bcd9238469b577dc1a099f8c978277..c21e8115f8838b1ff8ef747d79af1e804e00e0ab 100644
--- a/ui/accessibility/ax_enums.idl
+++ b/ui/accessibility/ax_enums.idl
@@ -279,6 +279,7 @@
     table_cell_column_span,
     table_cell_row_index,
     table_cell_row_span,
+    sort_direction,
 
     // Tree control attributes.
     hierarchical_level,
@@ -407,4 +408,11 @@
     invalid_state_other
   };
 
+  [cpp_enum_prefix_override="ax"] enum AXSortDirection {
+    sort_direction_unsorted,
+    sort_direction_ascending,
+    sort_direction_descending,
+    sort_direction_other
+  };
+
 };