Enable Chrome to tweak search engines for some locales

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);
 
 // Loads the set of TemplateURLs from the prepopulate data. On return,
 // |default_search_provider_index| is set to the index of the default search
 // provider.
 std::vector<std::unique_ptr<TemplateURLData>> GetPrepopulatedEngines(
     PrefService* prefs,
     size_t* default_search_provider_index);
 
+// Loads extra prepopulated engines for the given locale. If the engines are
+// already loaded, need_to-load will be set false.

[Peter Kasting, 2016/09/19 21:06:23]

Nit: How about this (I rewrote both functions' comments for parallelism, focus
on the second one):

// 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);

// 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.
std::vector<std::unique_ptr<TemplateURLData>>
GetPrepopulatedEnginesForNonDefaultLocale(const std::string& locale,
                                          PrefService* prefs);

This fixes these issues:
* Document the expected format of |locale|, since a "locale" can be many things.
* Document that this checks the current country and avoids doing anything if the
locale matches
* Avoid outparam entirely, since it's confusing, and callers can just check if
the returned vector is empty.

[Ian Wen, 2016/09/20 04:48:03]

Done.

+std::vector<std::unique_ptr<TemplateURLData>> GetLocalPrepopulatedEngines(

[Peter Kasting, 2016/09/19 21:06:23]

Should this function be #if'd for Android-only?  It seems like that's the only
place it's called.

[Ian Wen, 2016/09/20 04:48:03]

Done.

+    const std::string& locale,
+    PrefService* prefs,
+    bool* need_to_load);
+
 // Returns all prepopulated engines for all locales. Used only by tests.
 std::vector<const PrepopulatedEngine*> GetAllPrepopulatedEngines();
 
 // Returns a TemplateURLData for the specified prepopulated engine.
 std::unique_ptr<TemplateURLData> MakeTemplateURLDataFromPrepopulatedEngine(
     const PrepopulatedEngine& engine);
 
 // Removes prepopulated engines and their version stored in user prefs.
 void ClearPrepopulatedEnginesInPrefs(PrefService* prefs);
 
@@ skipping 12 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_