Implemented IAccessible2 reverse relations.

ui/accessibility/ax_enums.idl

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // These should be kept in sync with third_party/WebKit/public/web/WebAXEnums.h
 // until the Chromium and Blink trees are merged.
 [camel_case_enum_to_string=true] namespace ui {
 
   // For new entries to the following three enums, also add to
   // chrome/common/extensions/api/automation.idl.
@@ skipping 287 matching lines @@
     // What information was used to compute the object's name
     // (of type AXNameFrom).
     name_from,
 
     // What information was used to compute the object's description
     // (of type AXDescriptionFrom).
     description_from,
 
     // Relationships between this element and other elements.
     activedescendant_id,
+    member_of_id,
     next_on_line_id,
     previous_on_line_id,
 
     // Identifies a child tree which this node hosts.
     child_tree_id,
 
     // Position or Number of items in current set of listitems or treeitems
     set_size,
     pos_in_set,
 
@@ skipping 186 matching lines @@
     swipe_left_3,
     swipe_up_3,
     swipe_right_3,
     swipe_down_3,
     swipe_left_4,
     swipe_up_4,
     swipe_right_4,
     swipe_down_4
   };
 };