Move HTMLTagCollection to its own file

Source/core/html/HTMLCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. 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 14 matching lines @@
 #include "core/html/HTMLCollection.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/ClassCollection.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/NodeRareData.h"
 #include "core/html/DocumentNameCollection.h"
 #include "core/html/HTMLElement.h"
 #include "core/html/HTMLObjectElement.h"
 #include "core/html/HTMLOptionElement.h"
+#include "core/html/HTMLTagCollection.h"
 #include "core/html/WindowNameCollection.h"
 #include "wtf/HashSet.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 static bool shouldTypeOnlyIncludeDirectChildren(CollectionType type)
 {
     switch (type) {
@@ skipping 472 matching lines @@
 }
 
 void HTMLCollection::trace(Visitor* visitor)
 {
     visitor->trace(m_namedItemCache);
     visitor->trace(m_collectionIndexCache);
     LiveNodeListBase::trace(visitor);
 }
 
 } // namespace WebCore