Update the Speak answers back switch item.

ios/chrome/browser/ui/settings/voicesearch_collection_view_controller.mm

 // Copyright 2015 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 "ios/chrome/browser/ui/settings/voicesearch_collection_view_controller.h"
 
 #import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #import "base/mac/scoped_nsobject.h"
@@ skipping 219 matching lines @@
   BOOL enabled = [self currentLanguageSupportsTTS];
   BOOL on = enabled && _ttsEnabled.GetValue();
 
   UISwitch* switchView = switchCell.switchView;
   switchView.enabled = enabled;
   switchCell.textLabel.textColor =
       [CollectionViewSwitchCell defaultTextColorForState:switchView.state];
   if (on != switchView.isOn) {
     [switchView setOn:on animated:YES];
   }
+  // Also update the switch item.
+  CollectionViewSwitchItem* switchItem =
+      base::mac::ObjCCastStrict<CollectionViewSwitchItem>(
+          [self.collectionViewModel itemAtIndexPath:switchPath]);
+  switchItem.enabled = enabled;
+  switchItem.on = on;
 
   [self reconfigureCellsForItems:modifiedItems];
 }
 
 - (BOOL)currentLanguageSupportsTTS {
   voice::SpeechInputLocaleConfig* localeConfig =
       voice::SpeechInputLocaleConfig::GetInstance();
   std::string localeCode = _selectedLanguage.GetValue().empty()
                                ? localeConfig->GetDefaultLocale().code
                                : _selectedLanguage.GetValue();
   return localeConfig->IsTextToSpeechEnabledForCode(localeCode);
 }
 
 @end