MacViews/a11y: Allow accessibility clients to update the selected text.

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 57 matching lines @@
   // 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.
+  // things like logging into portals or filling forms. Set the second argument

[msw, 2016/10/27 17:55:09]

optional nit: make comments regarding this flag consistent.

[Patti Lor, 2016/10/31 00:35:05]

Done (with some edits because using the variable names doesn't make sense in
this context).

+  // to true to clear the existing value first, false to replace the currently
+  // selected text.
   //
   // 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;
+  base::Callback<void(const base::string16&, bool)> set_value_callback;
 
  private:
   uint32_t state_;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_VIEW_STATE_H_