Add support for 'order' on grid items

Source/core/rendering/OrderIterator.h

 /*
  * Copyright (C) 2011 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 19 matching lines @@
 
 #ifndef OrderIterator_h
 #define OrderIterator_h
 
 #include "wtf/Noncopyable.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class RenderBox;
-class RenderFlexibleBox;
 
 class OrderIterator {
     WTF_MAKE_NONCOPYABLE(OrderIterator);
 public:
-    OrderIterator(const RenderFlexibleBox*);
+    OrderIterator(const RenderBox*);
+
     void setOrderValues(Vector<int>&);
     RenderBox* currentChild() const { return m_currentChild; }
     RenderBox* first();
     RenderBox* next();
     void reset();
 
 private:
-    const RenderFlexibleBox* m_flexibleBox;
+    const RenderBox* m_containerBox;
     RenderBox* m_currentChild;
     Vector<int> m_orderValues;
     Vector<int>::const_iterator m_orderValuesIterator;
 };
 
 } // namespace WebCore
 
 #endif //  OrderIterator_h