Introduce LiteralSet

Source/core/dom/QualifiedName.cpp

 /*
  * Copyright (C) 2005, 2006, 2009 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 156 matching lines @@
 void createQualifiedName(void* targetAddress, StringImpl* name, const AtomicString& nameNamespace)
 {
     new (reinterpret_cast<void*>(targetAddress)) QualifiedName(nullAtom, AtomicString(name), nameNamespace);
 }
 
 void createQualifiedName(void* targetAddress, StringImpl* name)
 {
     new (reinterpret_cast<void*>(targetAddress)) QualifiedName(nullAtom, AtomicString(name), nullAtom);
 }
 
+bool lessThanByImplAddress(const QualifiedName* const& a, const QualifiedName* const& b)
+{
+    return a->impl() < b->impl();
 }
+
+bool lessThanByLocalNameImplAddress(const QualifiedName* const& a, const QualifiedName* const& b)
+{
+    return a->localName().impl() < b->localName().impl();
+}
+
+}