Remove needsShadowTreeWalker flag

Source/core/dom/NodeRenderingTraversal.h

 /*
  * Copyright (C) 2012 Google Inc. 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 48 matching lines @@
     }
 
 private:
     InsertionPoint* m_insertionPoint;
     bool m_resetStyleInheritance;
     bool m_outOfComposition;
 };
 
 ContainerNode* parent(const Node*);
 ContainerNode* parent(const Node*, ParentDetails*);
-ContainerNode* parentSlow(const Node*, ParentDetails*);
 Node* nextSibling(const Node*);
-Node* nextSiblingSlow(const Node*);
 Node* previousSibling(const Node*);
-Node* previousSiblingSlow(const Node*);
 
 Node* nextInScope(const Node*);
 Node* previousInScope(const Node*);
 Node* parentInScope(const Node*);
 Node* lastChildInScope(const Node*);
 
 inline ContainerNode* parent(const Node* node)
 {
     ParentDetails unusedDetails;
     return parent(node, &unusedDetails);
 }
 
-inline ContainerNode* parent(const Node* node, ParentDetails* details)
-{
-    if (!node->needsShadowTreeWalker()) {
-#ifndef NDEBUG
-        ParentDetails slowDetails;
-        ASSERT(node->parentNode() == parentSlow(node, &slowDetails));
-        ASSERT(slowDetails == *details);
-#endif
-        return node->parentNodeGuaranteedHostFree();
-    }
-
-    return parentSlow(node, details);
-}
-
-inline Node* nextSibling(const Node* node)
-{
-    if (!node->needsShadowTreeWalker()) {
-        Node* next = node->nextSibling();
-        if (!next || !next->isInsertionPoint()) {
-            ASSERT(nextSiblingSlow(node) == next);
-            return next;
-        }
-    }
-
-    return nextSiblingSlow(node);
-}
-
-inline Node* previousSibling(const Node* node)
-{
-    if (!node->needsShadowTreeWalker()) {
-        Node* prev = node->previousSibling();
-        if (!prev || !prev->isInsertionPoint()) {
-            ASSERT(previousSiblingSlow(node) == prev);
-            return prev;
-        }
-    }
-
-    return previousSiblingSlow(node);
-}
-
 }
 
 } // namespace WebCore
 
 #endif