Compute the normal flow list on the fly

Source/core/paint/DeprecatedPaintLayerStackingNodeIterator.h

 /*
  * Copyright (C) 2013 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 25 matching lines @@
 namespace blink {
 
 enum ChildrenIteration {
     NegativeZOrderChildren = 1,
     NormalFlowChildren = 1 << 1,
     PositiveZOrderChildren = 1 << 2,
     AllChildren = NegativeZOrderChildren | NormalFlowChildren | PositiveZOrderChildren
 };
 
 class DeprecatedPaintLayerStackingNode;
+class DeprecatedPaintLayer;
 
 // This iterator walks the DeprecatedPaintLayerStackingNode lists in the following order:
 // NegativeZOrderChildren -> NormalFlowChildren -> PositiveZOrderChildren.
 class DeprecatedPaintLayerStackingNodeIterator {
     WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNodeIterator);
 public:
-    DeprecatedPaintLayerStackingNodeIterator(const DeprecatedPaintLayerStackingNode& root, unsigned whichChildren)
-        : m_root(root)
-        , m_remainingChildren(whichChildren)
-        , m_index(0)
-    {
-    }
+    DeprecatedPaintLayerStackingNodeIterator(const DeprecatedPaintLayerStackingNode& root, unsigned whichChildren);
 
     DeprecatedPaintLayerStackingNode* next();
 
 private:
     const DeprecatedPaintLayerStackingNode& m_root;
     unsigned m_remainingChildren;
     unsigned m_index;
+    DeprecatedPaintLayer* m_currentNormalFlowChild;
 };
 
 // This iterator is similar to DeprecatedPaintLayerStackingNodeIterator but it walks the lists in reverse order
 // (from the last item to the first one).
 class DeprecatedPaintLayerStackingNodeReverseIterator {
     WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNodeReverseIterator);
 public:
     DeprecatedPaintLayerStackingNodeReverseIterator(const DeprecatedPaintLayerStackingNode& root, unsigned whichChildren)
         : m_root(root)
         , m_remainingChildren(whichChildren)
     {
         setIndexToLastItem();
     }
 
     DeprecatedPaintLayerStackingNode* next();
 
 private:
     void setIndexToLastItem();
 
     const DeprecatedPaintLayerStackingNode& m_root;
     unsigned m_remainingChildren;
     int m_index;
+    DeprecatedPaintLayer* m_currentNormalFlowChild;
 };
 
 } // namespace blink
 
 #endif // DeprecatedPaintLayerStackingNodeIterator_h