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

ui/views/controls/textfield/textfield.h

 // Copyright (c) 2012 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_VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_H_
 #define UI_VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 329 matching lines @@
 
   // View overrides:
   // Declared final since overriding by subclasses would interfere with the
   // accounting related to the scheduled text edit command. Subclasses should
   // use TextfieldController::HandleKeyEvent, to intercept the key event.
   bool OnKeyPressed(const ui::KeyEvent& event) final;
   bool OnKeyReleased(const ui::KeyEvent& event) final;
 
   // Handles a request to change the value of this text field from software
   // using an accessibility API (typically automation software, screen readers
-  // don't normally use this). Sets the value and clears the selection.
-  void AccessibilitySetValue(const base::string16& new_value);
+  // don't normally use this). If |clear_first| is true, clears the existing
+  // value first and sets it to |new_value|. If false, deletes whatever's
+  // selected and replaces it with |new_value|. Then clears the text selection.
+  void AccessibilitySetValue(const base::string16& new_value, bool clear_first);
 
   // Updates the painted background color.
   void UpdateBackgroundColor();
 
   // Updates the border per the state of |invalid_|.
   void UpdateBorder();
 
   // Does necessary updates when the text and/or cursor position changes.
   void UpdateAfterChange(bool text_changed, bool cursor_changed);
 
@@ skipping 173 matching lines @@
 
   // Used to bind callback functions to this object.
   base::WeakPtrFactory<Textfield> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Textfield);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_TEXTFIELD_TEXTFIELD_H_