Make extensions DSE persistent in browser prefs

components/search_engines/template_url_prepopulate_data.h

 // Copyright 2014 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 COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_PREPOPULATE_DATA_H_
 #define COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_PREPOPULATE_DATA_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 24 matching lines @@
 // file then it returns the version specified there.
 int GetDataVersion(PrefService* prefs);
 
 // Returns the prepopulated URLs for the current country.
 // |default_search_provider_index| is set to the index of the default search
 // provider within the returned vector.
 std::vector<std::unique_ptr<TemplateURLData>> GetPrepopulatedEngines(
     PrefService* prefs,
     size_t* default_search_provider_index);
 
+// Find the prepopulated search engine with the given id.
+std::unique_ptr<TemplateURLData> GetPrepopulatedEngine(PrefService* prefs,
+                                                       int prepopulated_id);
+
 #if defined(OS_ANDROID)
 // Returns the prepopulated URLs associated with |locale|, if it differs from
 // the current country.  |locale| should be a two-character uppercase ISO 3166-1
 // country code. If the given locale is the same as the existing locale, returns
 // an empty vector.
 std::vector<std::unique_ptr<TemplateURLData>> GetLocalPrepopulatedEngines(
     const std::string& locale,
     PrefService* prefs);
 #endif
 
@@ skipping 18 matching lines @@
 // of search engines when user switches device region settings. For use on iOS
 // only.
 // TODO(ios): Once user can customize search engines ( http://crbug.com/153047 )
 // this declaration should be removed and the definition in the .cc file be
 // moved back to the anonymous namespace.
 int GetCurrentCountryID();
 
 }  // namespace TemplateURLPrepopulateData
 
 #endif  // COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_PREPOPULATE_DATA_H_