[Mac] Preserve original selection when suggesting completions with diacritics

chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.mm

 // 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.
 
 #include "chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.h"
 
 #include <Carbon/Carbon.h>  // kVK_Return
 
 #include "base/mac/foundation_util.h"
 #include "base/memory/ptr_util.h"
@@ skipping 306 matching lines @@
   if (do_coalesced_range_update_)
     SetSelectedRange(coalesced_range_update_);
   do_coalesced_range_update_ = false;
 }
 
 base::string16 OmniboxViewMac::GetText() const {
   return base::SysNSStringToUTF16([field_ stringValue]);
 }
 
 NSRange OmniboxViewMac::GetSelectedRange() const {
-  return [[field_ currentEditor] selectedRange];
+  AutocompleteTextFieldEditor* editor =
+      base::mac::ObjCCastStrict<AutocompleteTextFieldEditor>(
+          [field_ currentEditor]);
+  return editor.actualSelectedRange;
 }
 
 NSRange OmniboxViewMac::GetMarkedRange() const {
   DCHECK([field_ currentEditor]);
   return [(NSTextView*)[field_ currentEditor] markedRange];
 }
 
 void OmniboxViewMac::SetSelectedRange(const NSRange range) {
   if (in_coalesced_update_block_) {
     do_coalesced_range_update_ = true;
@@ skipping 776 matching lines @@
                               display_text);
   NSDictionary* notification_info = @{
       NSAccessibilityAnnouncementKey : announcement,
       NSAccessibilityPriorityKey :     @(NSAccessibilityPriorityHigh)
   };
   NSAccessibilityPostNotificationWithUserInfo(
       [field_ window],
       NSAccessibilityAnnouncementRequestedNotification,
       notification_info);
 }