Use unique IDs for accessibility nodes on Android

ui/accessibility/platform/ax_platform_node_win.h

 // Copyright 2015 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.
 
 #ifndef UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_
 #define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_
 
 #include <atlbase.h>
 #include <atlcom.h>
 #include <oleacc.h>
@@ skipping 279 matching lines @@
   // Convert from a IA2TextBoundaryType to a ui::TextBoundaryType.
   ui::TextBoundaryType IA2TextBoundaryToTextBoundary(IA2TextBoundaryType type);
 
   // Search forwards (direction == 1) or backwards (direction == -1)
   // from the given offset until the given boundary is found, and
   // return the offset of that boundary.
   LONG FindBoundary(const base::string16& text,
                     IA2TextBoundaryType ia2_boundary,
                     LONG start_offset,
                     ui::TextBoundaryDirection direction);
-
-  // A windows-specific unique ID for this object. It's returned in
-  // IAccessible2::get_uniqueID, but more importantly it's used for
-  // firing events. On Windows, we fire events on the nearest parent HWND
-  // and pass the unique ID as the child id parameter. When the client
-  // wants to retrieve the object the event was fired on, it calls
-  // get_accChild and passes the child ID. We use negative IDs for the unique
-  // ID so we can distinguish a request for an arbitrary child from a request
-  // for an immediate child of an object by its 0-based index.
-  LONG unique_id_win_;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_WIN_H_