Make HTMLNames threadsafe

Source/WTF/wtf/text/AtomicString.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
  * Copyright (C) 2012 Google 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.
  *
@@ skipping 415 matching lines @@
 
 PassRefPtr<StringImpl> AtomicString::addSlowCase(StringImpl* r)
 {
     if (!r->length())
         return StringImpl::empty();
 
     AtomicStringTableLocker locker;
     StringImpl* result = *stringTable().add(r).iterator;
     if (result == r)
         r->setIsAtomic(true);
+    ASSERT(!r->isStatic() || result->isStatic());
     return result;
 }
 
 template<typename CharacterType>
 static inline HashSet<StringImpl*>::iterator findString(const StringImpl* stringImpl)
 {
     HashAndCharacters<CharacterType> buffer = { stringImpl->existingHash(), stringImpl->getCharacters<CharacterType>(), stringImpl->length() };
     return stringTable().find<HashAndCharacters<CharacterType>, HashAndCharactersTranslator<CharacterType> >(buffer);
 }
 
@@ skipping 49 matching lines @@
 }
 
 #ifndef NDEBUG
 void AtomicString::show() const
 {
     m_string.show();
 }
 #endif
 
 } // namespace WTF