Remove redundant m_isItemCacheValid flag from LiveNodeListBase

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.
  *
  * 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 373 matching lines @@
         return traverseMatchingElementsForwardToOffset(static_cast<const ClassNodeList*>(this), offset, toElement(currentNode), currentOffset, root);
     default:
         return traverseMatchingElementsForwardToOffset(this, offset, toElement(currentNode), currentOffset, root);
     }
 }
 
 bool ALWAYS_INLINE LiveNodeListBase::isLastItemCloserThanLastOrCachedItem(unsigned offset) const
 {
     ASSERT(isLengthCacheValid());
     unsigned distanceFromLastItem = cachedLength() - offset;
-    if (!isItemCacheValid())
+    if (!cachedItem())
         return distanceFromLastItem < offset;
 
     return cachedItemOffset() < offset && distanceFromLastItem < offset - cachedItemOffset();
 }
 
 bool ALWAYS_INLINE LiveNodeListBase::isFirstItemCloserThanCachedItem(unsigned offset) const
 {
-    ASSERT(isItemCacheValid());
     if (cachedItemOffset() < offset)
         return false;
 
     unsigned distanceFromCachedItem = cachedItemOffset() - offset;
     return offset < distanceFromCachedItem;
 }
 
 unsigned LiveNodeListBase::length() const
 {
     if (isLengthCacheValid())
         return cachedLength();
 
     item(UINT_MAX);
     ASSERT(isLengthCacheValid());
 
     return cachedLength();
 }
 
 // FIXME: It is silly that these functions are in HTMLCollection.cpp.
 Node* LiveNodeListBase::item(unsigned offset) const
 {
-    if (isItemCacheValid() && cachedItemOffset() == offset)
+    if (cachedItem() && cachedItemOffset() == offset)
         return cachedItem();
 
     if (isLengthCacheValid() && cachedLength() <= offset)
         return 0;
 
     ContainerNode* root = rootContainerNode();
     if (!root) {
         // FIMXE: In someTextNode.childNodes case the root is Text. We shouldn't even make a LiveNodeList for that.
         setLengthCache(0);
         return 0;
     }
 
     if (isLengthCacheValid() && !overridesItemAfter() && isLastItemCloserThanLastOrCachedItem(offset)) {
         Node* lastItem = itemBefore(0);
         ASSERT(lastItem);
         setItemCache(lastItem, cachedLength() - 1);
-    } else if (!isItemCacheValid() || isFirstItemCloserThanCachedItem(offset) || (overridesItemAfter() && offset < cachedItemOffset())) {
+    } else if (!cachedItem() || isFirstItemCloserThanCachedItem(offset) || (overridesItemAfter() && offset < cachedItemOffset())) {
         Node* firstItem;
         if (isLiveNodeListType(type()))
             firstItem = static_cast<const LiveNodeList*>(this)->traverseToFirstElement(*root);
         else
             firstItem = static_cast<const HTMLCollection*>(this)->traverseToFirstElement(*root);
 
         if (!firstItem) {
             setLengthCache(0);
             return 0;
         }
@@ skipping 209 matching lines @@
 
 void HTMLCollection::append(NodeCacheMap& map, const AtomicString& key, Element* element)
 {
     OwnPtr<Vector<Element*> >& vector = map.add(key.impl(), nullptr).iterator->value;
     if (!vector)
         vector = adoptPtr(new Vector<Element*>);
     vector->append(element);
 }
 
 } // namespace WebCore