Translate: split language code typo correction to apply unit tests.

chrome/renderer/translate_helper.h

Index: chrome/renderer/translate_helper.h
diff --git a/chrome/renderer/translate_helper.h b/chrome/renderer/translate_helper.h
index dab2006a36723740f4de75da380fb81f65714b3c..b5f3ea180784d9dad5aef685ed0819cc2ad6455c 100644
--- a/chrome/renderer/translate_helper.h
+++ b/chrome/renderer/translate_helper.h
@@ -66,8 +66,12 @@ class TranslateHelper : public content::RenderViewObserver {
   virtual bool DontDelayTasks();
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, LanguageCodeTypoCorrection);
   FRIEND_TEST_ALL_PREFIXES(TranslateHelperTest, LanguageCodeSynonyms);
 
+  // Correct language code if it contains well-known mistakes.
+  static void CorrectLanguageCodeTypo(std::string* code);
+
   // Convert language code to the one used in server supporting list.
   static void ConvertLanguageCodeSynonym(std::string* code);