Make extensions DSE persistent in browser prefs

components/search_engines/template_url_prepopulate_data.cc

 // 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.
 
 #include "components/search_engines/template_url_prepopulate_data.h"
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 #include <locale.h>
 #endif
 
@@ skipping 1023 matching lines @@
   // the built-in set.
   *default_search_provider_index = 0;
   std::vector<std::unique_ptr<TemplateURLData>> t_urls =
       GetPrepopulatedTemplateURLData(prefs);
   if (!t_urls.empty())
     return t_urls;
 
   return GetPrepopulationSetFromCountryID(GetCountryIDFromPrefs(prefs));
 }
 
+// Find the prepopulated search engine with the given id.
+std::unique_ptr<TemplateURLData> GetPrepopulatedEngine(PrefService* prefs,
+                                                       int prepopulated_id) {
+  size_t default_index;

[Peter Kasting, 2016/12/22 20:49:04]

Nit: Probably should be done in a separate CL, but it seems like this isn't the
only caller that doesn't really care about this value.  Probably
GetPrepopulatedEngines() should change to allow its second arg to be null for
callers that don't care.

[Alexander Yashkin, 2016/12/23 19:44:09]

Agree, it should be done, but in separate CL.

+  std::vector<std::unique_ptr<TemplateURLData>> engines =

[Peter Kasting, 2016/12/22 20:49:04]

Nit: Use auto

[Alexander Yashkin, 2016/12/23 19:44:09]

Done

+      TemplateURLPrepopulateData::GetPrepopulatedEngines(prefs, &default_index);
+  for (auto& engine : engines) {
+    if (engine->prepopulate_id == prepopulated_id)
+      return std::move(engine);
+  }

[Peter Kasting, 2016/12/22 20:49:04]

I tried writing this out with find_if(), but I don't know whether it's better in
the end.  It would probably be better with generic lambdas, but we don't support
C++14.

Up to you if you think this is worth using.

  auto Pred = [prepopulate_id](const std::unique_ptr<TemplateURLData>& data) {
    return data->prepopulate_id == prepopulate_id;
  };
  auto it = std::find_if(engines.begin(), engines.end(), Pred);
  return it == engines.end() ? nullptr : std::move(*it);

[Alexander Yashkin, 2016/12/23 19:44:09]

Old style is more clear here, IMHO.

+  return nullptr;
+}
+
 #if defined(OS_ANDROID)
 
 std::vector<std::unique_ptr<TemplateURLData>> GetLocalPrepopulatedEngines(
     const std::string& locale,
     PrefService* prefs) {
   int country_id = CountryStringToCountryID(locale);
   if (country_id == kCountryIDUnknown ||
       country_id == GetCountryIDFromPrefs(prefs)) {
     return std::vector<std::unique_ptr<TemplateURLData>>();
   }
@@ skipping 106 matching lines @@
   locale_str.erase(0, territory_delim + 1);
 
   // Next remove any codeset/modifier portion and uppercase.
   return CountryStringToCountryID(
       base::ToUpperASCII(locale_str.substr(0, locale_str.find_first_of(".@"))));
 }
 
 #endif  // OS_*
 
 }  // namespace TemplateURLPrepopulateData