Mark DOMStringList.contains() as deprecated, add console warning.

Source/core/dom/DOMStringList.h

 /*
  * Copyright (C) 2010 Google 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 35 matching lines @@
         return adoptRefWillBeNoop(new DOMStringList());
     }
 
     bool isEmpty() const { return m_strings.isEmpty(); }
     void clear() { m_strings.clear(); }
     void append(const String& string) { m_strings.append(string); }
     void sort();
 
     // Implements the IDL.
     size_t length() const { return m_strings.size(); }
+    String anonymousIndexedGetter(unsigned index) const { return item(index); }
     String item(unsigned index) const;
     bool contains(const String& str) const;
 
     operator const Vector<String>&() const { return m_strings; }
 
     DEFINE_INLINE_TRACE() { }
 
 private:
     DOMStringList() { }
 
     Vector<String> m_strings;
 };
 
 } // namespace blink
 
 #endif // DOMStringList_h