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

ui/accessibility/platform/ax_platform_node_delegate.h

 // Copyright 2014 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_DELEGATE_H_
 #define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_DELEGATE_H_
 
 #include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_export.h"
 #include "ui/gfx/geometry/vector2d.h"
@@ skipping 67 matching lines @@
 
   //
   // Actions.
   //
 
   // Perform the default action, e.g. click a button, follow a link, or
   // toggle a checkbox.
   virtual void DoDefaultAction() = 0;
 
   // Change the value of a control, such as the text content of a text field.
-  virtual bool SetStringValue(const base::string16& new_value) = 0;
+  // Set |clear_first| to true to clear the existing value first, false to
+  // replace the currently selected text.
+  virtual bool SetStringValue(const base::string16& new_value,
+                              bool clear_first) = 0;
 
-  // Whether the string value is settable.
+  // Whether SetStringValue() is callable, i.e. if the string value is read only

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

nit: do you mean "if the textfield is not read-only"?

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

Done, thanks!

+  // and if the callback exists.
   virtual bool CanSetStringValue() = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_DELEGATE_H_