Refactor LayoutTreeBuilderTraversal to expose a cleaner interface to layout sibling nodes.

third_party/WebKit/Source/core/dom/LayoutTreeBuilderTraversal.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 43 matching lines @@
     }
 
    private:
     Member<const InsertionPoint> m_insertionPoint;
   };
 
   static ContainerNode* parent(const Node&, ParentDetails* = nullptr);
   static ContainerNode* layoutParent(const Node&, ParentDetails* = nullptr);
   static Node* firstChild(const Node&);
   static Node* nextSibling(const Node&);
+  static Node* nextLayoutSibling(const Node& node) {
+    int32_t limit = kTraverseAllSiblings;
+    return nextLayoutSibling(node, limit);
+  }
+  static Node* previousLayoutSibling(const Node& node) {
+    int32_t limit = kTraverseAllSiblings;
+    return previousLayoutSibling(node, limit);
+  }
   static Node* previousSibling(const Node&);
   static Node* previous(const Node&, const Node* stayWithin);
   static Node* next(const Node&, const Node* stayWithin);
   static Node* nextSkippingChildren(const Node&, const Node* stayWithin);
   static LayoutObject* parentLayoutObject(const Node&);
   static LayoutObject* nextSiblingLayoutObject(
       const Node&,
       int32_t limit = kTraverseAllSiblings);
   static LayoutObject* previousSiblingLayoutObject(
       const Node&,
       int32_t limit = kTraverseAllSiblings);
   static LayoutObject* nextInTopLayer(const Element&);
 
   static inline Element* parentElement(const Node& node) {
     ContainerNode* found = parent(node);
     return found && found->isElementNode() ? toElement(found) : 0;
   }
+
+ private:
+  static Node* nextLayoutSibling(const Node&, int32_t& limit);
+  static Node* previousLayoutSibling(const Node&, int32_t& limit);
 };
 
 }  // namespace blink
 
 #endif