Remove the user-defined empty WTF::String destructor

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 114 matching lines @@
 
 #if COMPILER_SUPPORTS(CXX_RVALUE_REFERENCES)
     // We have to declare the copy constructor and copy assignment operator as well, otherwise
     // they'll be implicitly deleted by adding the move constructor and move assignment operator.
     String(const String& other) : m_impl(other.m_impl) { }
     String(String&& other) : m_impl(other.m_impl.release()) { }
     String& operator=(const String& other) { m_impl = other.m_impl; return *this; }
     String& operator=(String&& other) { m_impl = other.m_impl.release(); return *this; }
 #endif
 
-    // Inline the destructor.
-    ALWAYS_INLINE ~String() { }
-
     void swap(String& o) { m_impl.swap(o.m_impl); }
 
     template<typename CharType>
     static String adopt(StringBuffer<CharType>& buffer)
     {
         if (!buffer.length())
             return StringImpl::empty();
         return String(buffer.release());
     }
 
@@ skipping 548 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