Add custom action support

ui/accessibility/ax_action_data.h

 // Copyright 2016 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_AX_ACTION_DATA_H_
 #define UI_ACCESSIBILITY_AX_ACTION_DATA_H_
 
 #include "base/strings/string16.h"
 #include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_export.h"
@@ skipping 27 matching lines @@
   int flags;
 
   // For an action that creates a selection, the selection anchor and focus
   // (see ax_tree_data.h for definitions).
   int anchor_node_id;
   int anchor_offset;
 
   int focus_node_id;
   int focus_offset;
 
+  // For custom action.
+  int custom_action_id;
+
   // The target rect for the action.
   gfx::Rect target_rect;
 
   // The target point for the action.
   gfx::Point target_point;
 
   // The new value for a node, for the SET_VALUE action.
   base::string16 value;
 
   // The event to fire in response to a HIT_TEST action.
   AXEvent hit_test_event_to_fire;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_ACTION_DATA_H_