Undo selection.

ui/views/controls/textfield/textfield_model.h

Index: ui/views/controls/textfield/textfield_model.h
diff --git a/ui/views/controls/textfield/textfield_model.h b/ui/views/controls/textfield/textfield_model.h
index 135524e289a44035be219830cdb0e1044f7febf1..dd03710719102bf23a97053b85dacddb48dad52c 100644
--- a/ui/views/controls/textfield/textfield_model.h
+++ b/ui/views/controls/textfield/textfield_model.h
@@ -65,7 +65,7 @@ class VIEWS_EXPORT TextfieldModel {
   // without worrying about messing edit history.
   bool SetText(const base::string16& new_text);
 
-  gfx::RenderText* render_text() { return render_text_.get(); }
+  gfx::RenderText* render_text() const { return render_text_.get(); }
 
   // Inserts given |new_text| at the current cursor position.
   // The current composition text will be cleared.
@@ -255,12 +255,12 @@ class VIEWS_EXPORT TextfieldModel {
   // 1) Delete the string from |delete_from| to |delte_to|.
   // 2) Insert the |new_text| at the index |new_text_insert_at|.
   //    Note that the index is after deletion.
-  // 3) Move the cursor to |new_cursor_pos|.
+  // 3) Select |selection_range|.
   void ModifyText(size_t delete_from,
                   size_t delete_to,
                   const base::string16& new_text,
                   size_t new_text_insert_at,
-                  size_t new_cursor_pos);
+                  gfx::Range selection_range);
 
   void ClearComposition();