Protector adds the default prepopulated engine if it was removed.

chrome/browser/search_engines/template_url_service.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.
 
 #ifndef CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_H_
 #define CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 127 matching lines @@
   const TemplateURL* GetTemplateURLForHost(const std::string& host) const;
 
   // Adds a new TemplateURL to this model. TemplateURLService will own the
   // reference, and delete it when the TemplateURL is removed.
   void Add(TemplateURL* template_url);
 
   // Removes the keyword from the model. This deletes the supplied TemplateURL.
   // This fails if the supplied template_url is the default search provider.
   void Remove(const TemplateURL* template_url);
 
+  // Updates the information in |existing_turl| using the information from
+  // |new_values|, but the ID for |existing_turl| is retained.
+  void Update(const TemplateURL* existing_turl, const TemplateURL& new_values);
+
   // Removes all auto-generated keywords that were created in the specified
   // range.
   void RemoveAutoGeneratedBetween(base::Time created_after,
                                   base::Time created_before);
 
   // Removes all auto-generated keywords that were created on or after the
   // date passed in.
   void RemoveAutoGeneratedSince(base::Time created_after);
 
   // If the given extension has an omnibox keyword, adds a TemplateURL for that
@@ skipping 431 matching lines @@
   // from Sync. This is to facilitate the fact that changes to the value of
   // prefs::kSyncedDefaultSearchProviderGUID do not always come before the
   // TemplateURL entry it refers to, and to handle the case when we want to use
   // the Synced default when the default search provider becomes unmanaged.
   bool pending_synced_default_search_;
 
   DISALLOW_COPY_AND_ASSIGN(TemplateURLService);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_H_