Remove wtf::String::characterAt.

third_party/WebKit/Source/wtf/text/WTFString.h

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 430 matching lines @@
 
     // Hash table deleted values, which are only constructed and never copied or
     // destroyed.
     String(WTF::HashTableDeletedValueType) : m_impl(WTF::HashTableDeletedValue) { }
     bool isHashTableDeletedValue() const { return m_impl.isHashTableDeletedValue(); }
 
 #ifndef NDEBUG
     void show() const;
 #endif
 
-    // Workaround for a compiler bug. Use operator[] instead.
-    UChar characterAt(unsigned index) const
-    {
-        if (!m_impl || index >= m_impl->length())
-            return 0;
-        return (*m_impl)[index];
-    }
-
 private:
     typedef struct ImplicitConversionFromWTFStringToBoolDisallowed* (String::*UnspecifiedBoolType);
     operator UnspecifiedBoolType() const;
 
     template <typename CharacterType>
     void removeInternal(const CharacterType*, unsigned, int);
 
     template <typename CharacterType>
     void appendInternal(CharacterType);
 
@@ skipping 236 matching lines @@
 using WTF::charactersToFloat;
 using WTF::equal;
 using WTF::equalIgnoringCase;
 using WTF::find;
 using WTF::isAllSpecialCharacters;
 using WTF::isSpaceOrNewline;
 using WTF::reverseFind;
 
 #include "wtf/text/AtomicString.h"
 #endif // WTFString_h