Stop passing the root node to node lists traversal functions

Source/core/html/CollectionIndexCache.h

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 46 matching lines @@
             return !cachedNodeIndex() && !nodeAt(collection, 1);
         return nodeAt(collection, 0) && !nodeAt(collection, 1);
     }
 
     unsigned nodeCount(const Collection&);
     NodeType* nodeAt(const Collection&, unsigned index);
 
     void invalidate();
 
 private:
-    NodeType* nodeBeforeCachedNode(const Collection&, unsigned index, const ContainerNode& root);
-    NodeType* nodeAfterCachedNode(const Collection&, unsigned index, const ContainerNode& root);
+    NodeType* nodeBeforeCachedNode(const Collection&, unsigned index);
+    NodeType* nodeAfterCachedNode(const Collection&, unsigned index);
 
     ALWAYS_INLINE NodeType* cachedNode() const { return m_currentNode; }
     ALWAYS_INLINE unsigned cachedNodeIndex() const { ASSERT(cachedNode()); return m_cachedNodeIndex; }
     ALWAYS_INLINE void setCachedNode(NodeType* node, unsigned index)
     {
         ASSERT(node);
         m_currentNode = node;
         m_cachedNodeIndex = index;
     }
 
@@ skipping 38 matching lines @@
 
     return cachedNodeCount();
 }
 
 template <typename Collection, typename NodeType>
 inline NodeType* CollectionIndexCache<Collection, NodeType>::nodeAt(const Collection& collection, unsigned index)
 {
     if (isCachedNodeCountValid() && index >= cachedNodeCount())
         return 0;
 
-    ContainerNode& root = collection.rootNode();
     if (cachedNode()) {
         if (index > cachedNodeIndex())
-            return nodeAfterCachedNode(collection, index, root);
+            return nodeAfterCachedNode(collection, index);
         if (index < cachedNodeIndex())
-            return nodeBeforeCachedNode(collection, index, root);
+            return nodeBeforeCachedNode(collection, index);
         return cachedNode();
     }
 
     // No valid cache yet, let's find the first matching element.
     ASSERT(!isCachedNodeCountValid());
-    NodeType* firstNode = collection.traverseToFirstElement(root);
+    NodeType* firstNode = collection.traverseToFirstElement();
     if (!firstNode) {
         // The collection is empty.
         setCachedNodeCount(0);
         return 0;
     }
     setCachedNode(firstNode, 0);
-    return index ? nodeAfterCachedNode(collection, index, root) : firstNode;
+    return index ? nodeAfterCachedNode(collection, index) : firstNode;
 }
 
 template <typename Collection, typename NodeType>
-inline NodeType* CollectionIndexCache<Collection, NodeType>::nodeBeforeCachedNode(const Collection& collection, unsigned index, const ContainerNode& root)
+inline NodeType* CollectionIndexCache<Collection, NodeType>::nodeBeforeCachedNode(const Collection& collection, unsigned index)
 {
     ASSERT(cachedNode()); // Cache should be valid.
     unsigned currentIndex = cachedNodeIndex();
     ASSERT(currentIndex > index);
 
     // Determine if we should traverse from the beginning of the collection instead of the cached node.
     bool firstIsCloser = index < currentIndex - index;
     if (firstIsCloser || !collection.canTraverseBackward()) {
-        NodeType* firstNode = collection.traverseToFirstElement(root);
+        NodeType* firstNode = collection.traverseToFirstElement();
         ASSERT(firstNode);
         setCachedNode(firstNode, 0);
-        return index ? nodeAfterCachedNode(collection, index, root) : firstNode;
+        return index ? nodeAfterCachedNode(collection, index) : firstNode;
     }
 
     // Backward traversal from the cached node to the requested index.
     NodeType* currentNode = cachedNode();
     ASSERT(collection.canTraverseBackward());
     while ((currentNode = collection.itemBefore(currentNode))) {
         ASSERT(currentIndex);
         --currentIndex;
         if (currentIndex == index) {
             setCachedNode(currentNode, currentIndex);
             return currentNode;
         }
     }
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 template <typename Collection, typename NodeType>
-inline NodeType* CollectionIndexCache<Collection, NodeType>::nodeAfterCachedNode(const Collection& collection, unsigned index, const ContainerNode& root)
+inline NodeType* CollectionIndexCache<Collection, NodeType>::nodeAfterCachedNode(const Collection& collection, unsigned index)
 {
     ASSERT(cachedNode()); // Cache should be valid.
     unsigned currentIndex = cachedNodeIndex();
     ASSERT(currentIndex < index);
 
     // Determine if we should traverse from the end of the collection instead of the cached node.
     bool lastIsCloser = isCachedNodeCountValid() && cachedNodeCount() - index < index - currentIndex;
     if (lastIsCloser && collection.canTraverseBackward()) {
         NodeType* lastItem = collection.itemBefore(0);
         ASSERT(lastItem);
         setCachedNode(lastItem, cachedNodeCount() - 1);
         if (index < cachedNodeCount() - 1)
-            return nodeBeforeCachedNode(collection, index, root);
+            return nodeBeforeCachedNode(collection, index);
         return lastItem;
     }
 
     // Forward traversal from the cached node to the requested index.
-    NodeType* currentNode = collection.traverseForwardToOffset(index, *cachedNode(), currentIndex, root);
+    NodeType* currentNode = collection.traverseForwardToOffset(index, *cachedNode(), currentIndex);
     if (!currentNode) {
         // Did not find the node. On plus side, we now know the length.
         setCachedNodeCount(currentIndex + 1);
         return 0;
     }
     setCachedNode(currentNode, currentIndex);
     return currentNode;
 }
 
 } // namespace WebCore
 
 #endif // CollectionIndexCache_h