Fix a crash in the translate info bar.

chrome/browser/translate/translate_infobar_delegate.h

 // Copyright (c) 2011 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 CHROME_BROWSER_TRANSLATE_TRANSLATE_INFOBAR_DELEGATE_H_
 #define CHROME_BROWSER_TRANSLATE_TRANSLATE_INFOBAR_DELEGATE_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 21 matching lines @@
     NONE,
     NORMAL_TO_ERROR,
     ERROR_TO_NORMAL
   };
 
   static const size_t kNoIndex;
 
   // Factory method to create a non-error translate infobar.
   // The original and target language specified are the ASCII language codes
   // (ex: en, fr...).
-  // Returns NULL if it failed, typically if |original_language| or
-  // |target_language| is not a supported language.
+  // CHECK if |original_language| or |target_language| is not a supported
+  // language, though |original_language| can be unknown if type is TRANSLATING.
   static TranslateInfoBarDelegate* CreateDelegate(
       Type infobar_type,
       TabContents* tab_contents,
       const std::string& original_language,
       const std::string& target_language);
 
   // Factory method to create an error translate infobar.
   static TranslateInfoBarDelegate* CreateErrorDelegate(
       TranslateErrors::Type error_type,
       TabContents* tab_contents,
@@ skipping 149 matching lines @@
   // The current infobar view.
   TranslateInfoBarView* infobar_view_;
 
   // The translation related preferences.
   TranslatePrefs prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateInfoBarDelegate);
 };
 
 #endif  // CHROME_BROWSER_TRANSLATE_TRANSLATE_INFOBAR_DELEGATE_H_