Oilpan: tidy up definition of some stack-allocated scope objects.

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 19 matching lines @@
 #include "core/dom/Element.h"
 
 namespace blink {
 
 class InsertionPoint;
 class RenderObject;
 
 namespace NodeRenderingTraversal {
 
 class ParentDetails {
+    STACK_ALLOCATED();
 public:
     ParentDetails()
-        : m_insertionPoint(0)
+        : m_insertionPoint(nullptr)
     { }
 
     const InsertionPoint* insertionPoint() const { return m_insertionPoint; }
 
     void didTraverseInsertionPoint(const InsertionPoint*);
 
     bool operator==(const ParentDetails& other)
     {
         return m_insertionPoint == other.m_insertionPoint;
     }
 
 private:
-    const InsertionPoint* m_insertionPoint;
+    RawPtrWillBeMember<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