Language.{h,cpp} clean-up.

Source/platform/Language.h

 /*
  * Copyright (C) 2003, 2006, 2010, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 14 matching lines @@
 
 #ifndef Language_h
 #define Language_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/Forward.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
+// Returns lowercased BCP-47 language tag such as "en-us".  This is the UI
+// locale of the browser application.
 PLATFORM_EXPORT AtomicString defaultLanguage();
+// Returns a list of lowercased BCP-47 language tags.  This never returns
+// multiple values in production.  This is not a value of Accept-Languages
+// header.  See ChromeClient::acceptLanguages.
 PLATFORM_EXPORT Vector<AtomicString> userPreferredLanguages();
-PLATFORM_EXPORT Vector<AtomicString> userPreferredLanguagesOverride();
 PLATFORM_EXPORT void overrideUserPreferredLanguages(const Vector<AtomicString>&);
 PLATFORM_EXPORT size_t indexOfBestMatchingLanguageInList(const AtomicString& language, const Vector<AtomicString>& languageList);
 
 }
 
 #endif