Use a composed tree based traversal in computing quads in LinkHighlight::computeQuads().

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 39 matching lines @@
     {
         return m_insertionPoint == other.m_insertionPoint;
     }
 
 private:
     const InsertionPoint* m_insertionPoint;
 };
 
 ContainerNode* parent(const Node*, ParentDetails* = 0);
 bool contains(const ContainerNode*, const Node*);
+Node* firstChild(const Node*);
 Node* nextSibling(const Node*);
 Node* previousSibling(const Node*);
 Node* previous(const Node*, const Node* stayWithin);
 Node* next(const Node*, const Node* stayWithin);
 RenderObject* nextSiblingRenderer(const Node*);
 RenderObject* previousSiblingRenderer(const Node*);
 RenderObject* nextInTopLayer(const Element*);
 
 inline Element* parentElement(const Node* node)
 {
     ContainerNode* found = parent(node);
     return found && found->isElementNode() ? toElement(found) : 0;
 }
 
 }
 
 } // namespace blink
 
 #endif