[Mac] Preserve original selection when suggesting completions with diacritics

chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_nsobject.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
 #import "chrome/browser/ui/cocoa/url_drop_target.h"
 
@@ skipping 21 matching lines @@
   // Indicates if the field editor's interpretKeyEvents: method is being called.
   // If it's YES, then we should postpone the call to the observer's
   // OnDidChange() method after the field editor's interpretKeyEvents: method
   // is finished, rather than calling it in textDidChange: method. Because the
   // input method may update the marked text after inserting some text, but we
   // need the observer be aware of the marked text as well.
   BOOL interpretingKeyEvents_;
 
   // Indicates if the text has been changed by key events.
   BOOL textChangedByKeyEvents_;
+
+  // The selected range as far as NSTextView is concerned.
+  // See |actualSelectedRange|.
+  NSRange visualSelectedRange_;
 }
 
 // The delegate is always an AutocompleteTextField*.  Override the superclass
 // implementations to allow for proper typing.
 - (AutocompleteTextField*)delegate;
 - (void)setDelegate:(AutocompleteTextField*)delegate;
 
 // Sets attributed string programatically through the field editor's text
 // storage object.
 - (void)setAttributedString:(NSAttributedString*)aString;
 
+// Stores requested selection range, before it's adjusted to grapheme
+// boundaries. This range is what text editing commands
+// will operate on, vs. |visualSelectionRange_|, which reflects the
+// range that looks highlighted.
+@property(nonatomic, readonly) NSRange actualSelectedRange;
+
 @end
 
 @interface AutocompleteTextFieldEditor(PrivateTestMethods)
 - (AutocompleteTextFieldObserver*)observer;
 - (void)pasteAndGo:sender;
 @end