Wire up an api to darken screen for accessibility

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"
 #include "ui/gfx/geometry/rect.h"
 
 namespace ui {
 
 // A compact representation of an accessibility action and the arguments
 // associated with that action.
 struct AX_EXPORT AXActionData {
   AXActionData();
   AXActionData(const AXActionData& other);
   virtual ~AXActionData();
 
+  // Add a boolean attribute to this action.
+  void AddBoolAttribute(AXActionBoolAttribute attribute, bool value);
+  bool GetBoolAttribute(AXActionBoolAttribute attr) const;
+
   // Return a string representation of this data, for debugging.
   virtual std::string ToString() const;
 
   // This is a simple serializable struct. All member variables should be
   // public and copyable.
 
   // See the AXAction enums in ax_enums.idl for explanations of which
   // parameters apply.
 
   // The action to take.
@@ skipping 14 matching lines @@
   int focus_offset;
 
   // 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;
+  std::vector<std::pair<AXActionBoolAttribute, bool>> bool_attributes;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_ACTION_DATA_H_