Introduce and use type casting functions for several HTMLCollection types

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 183 matching lines @@
 template <> inline bool isMatchingElement(const HTMLCollection& htmlCollection, const Element& element)
 {
     CollectionType type = htmlCollection.type();
 
     // These collections apply to any kind of Elements, not just HTMLElements.
     switch (type) {
     case DocAll:
     case NodeChildren:
         return true;
     case ClassCollectionType:
-        return static_cast<const ClassCollection&>(htmlCollection).elementMatches(element);
+        return toClassCollection(htmlCollection).elementMatches(element);
     case TagCollectionType:
-        return static_cast<const TagCollection&>(htmlCollection).elementMatches(element);
+        return toTagCollection(htmlCollection).elementMatches(element);
     case HTMLTagCollectionType:
-        return static_cast<const HTMLTagCollection&>(htmlCollection).elementMatches(element);
+        return toHTMLTagCollection(htmlCollection).elementMatches(element);
     default:
         break;
     }
 
     // The following only applies to HTMLElements.
     if (!element.isHTMLElement())
         return false;
 
     switch (type) {
     case DocImages:
@@ skipping 113 matching lines @@
     do {
         previous = ElementTraversal::previousSibling(*previous);
     } while (previous && !isMatchingElement(nodeList, *previous));
     return previous;
 }
 
 Element* HTMLCollection::traverseToFirstElement() const
 {
     switch (type()) {
     case HTMLTagCollectionType:
-        return firstMatchingElement(static_cast<const HTMLTagCollection&>(*this));
+        return firstMatchingElement(toHTMLTagCollection(*this));
     case ClassCollectionType:
-        return firstMatchingElement(static_cast<const ClassCollection&>(*this));
+        return firstMatchingElement(toClassCollection(*this));
     default:
         if (overridesItemAfter())
             return virtualItemAfter(0);
         if (shouldOnlyIncludeDirectChildren())
             return firstMatchingChildElement(*this);
         return firstMatchingElement(*this);
     }
 }
 
 Element* HTMLCollection::traverseToLastElement() const
@@ skipping 11 matching lines @@
     if (shouldOnlyIncludeDirectChildren())
         return nextMatchingChildElement(*this, previous);
     return nextMatchingElement(*this, previous);
 }
 
 Element* HTMLCollection::traverseForwardToOffset(unsigned offset, Element& currentElement, unsigned& currentOffset) const
 {
     ASSERT(currentOffset < offset);
     switch (type()) {
     case HTMLTagCollectionType:
-        return traverseMatchingElementsForwardToOffset(static_cast<const HTMLTagCollection&>(*this), offset, currentElement, currentOffset);
+        return traverseMatchingElementsForwardToOffset(toHTMLTagCollection(*this), offset, currentElement, currentOffset);
     case ClassCollectionType:
-        return traverseMatchingElementsForwardToOffset(static_cast<const ClassCollection&>(*this), offset, currentElement, currentOffset);
+        return traverseMatchingElementsForwardToOffset(toClassCollection(*this), offset, currentElement, currentOffset);
     default:
         if (overridesItemAfter()) {
             Element* next = &currentElement;
             while ((next = virtualItemAfter(next))) {
                 if (++currentOffset == offset)
                     return next;
             }
             return 0;
         }
         if (shouldOnlyIncludeDirectChildren()) {
@@ skipping 127 matching lines @@
 }
 
 void HTMLCollection::trace(Visitor* visitor)
 {
     visitor->trace(m_namedItemCache);
     visitor->trace(m_collectionIndexCache);
     LiveNodeListBase::trace(visitor);
 }
 
 } // namespace WebCore