Mac a11y: Add Help, TopLevelUIElement, and Window accessibility attributes.

ui/accessibility/ax_view_state.h

 // Copyright (c) 2011 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_VIEW_STATE_H_
 #define UI_ACCESSIBILITY_AX_VIEW_STATE_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
@@ skipping 39 matching lines @@
 
   // The name of the default action if the user clicks on this view.
   base::string16 default_action;
 
   // The keyboard shortcut to activate this view, if any.
   base::string16 keyboard_shortcut;
 
   // The view's placeholder value, used only for views with editable text.
   base::string16 placeholder;
 
+  // The view's help text, set to the view's tooltip text (if any).
+  base::string16 help_text;
+
   // The selection start and end. Only applies to views with text content,
   // such as a text box or combo box; start and end should be -1 otherwise.
   int selection_start;
   int selection_end;
 
   // The selected item's index and the count of the number of items.
   // Only applies to views with multiple choices like a listbox; both
   // index and count should be -1 otherwise.
   int index;
   int count;
 
   // An optional callback that can be used by accessibility clients to
   // set the string value of this view. This only applies to roles where
   // setting the value makes sense, like a text box. Not often used by
   // screen readers, but often used by automation software to script
   // things like logging into portals or filling forms.
   //
   // This callback is only valid for the lifetime of the view, and should
   // be a safe no-op if the view is deleted. Typically, accessible views
   // should use a WeakPtr when binding the callback.
   base::Callback<void(const base::string16&)> set_value_callback;
 
  private:
   uint32_t state_;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_VIEW_STATE_H_