[Translate] Apply language synonyms to the target language

chrome/browser/translate/translate_prefs.h

Index: chrome/browser/translate/translate_prefs.h
diff --git a/chrome/browser/translate/translate_prefs.h b/chrome/browser/translate/translate_prefs.h
index 583bd825d645d191527f60ecb4b49a4defbd8a7c..1532372ee6109e9578d9321e810fda259c63f73e 100644
--- a/chrome/browser/translate/translate_prefs.h
+++ b/chrome/browser/translate/translate_prefs.h
@@ -95,6 +95,12 @@ class TranslatePrefs {
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
   static void MigrateUserPrefs(PrefService* user_prefs);
 
+  // Converts the language code for Translate. This removes the sub code (like
+  // -US) except for Chinese, and converts the synonyms.
+  // The same logic exists at language_options.js, and please keep consistency
+  // with the JavaScript file.
+  static std::string ConvertLangCodeForTranslation(const std::string &lang);
+
  private:
   friend class TranslatePrefsTest;
   FRIEND_TEST_ALL_PREFIXES(TranslatePrefsTest, CreateBlockedLanguages);