Add a use counter to determine compat impact of changing flexbox's intrinsic size calculation

Source/core/layout/LayoutFlexibleBox.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 149 matching lines @@
     void prepareChildForPositionedLayout(LayoutBox& child, LayoutUnit mainAxisOffset, LayoutUnit crossAxisOffset, PositionedLayoutMode);
     size_t numberOfInFlowPositionedChildren(const OrderedFlexItemList&) const;
     void layoutAndPlaceChildren(LayoutUnit& crossAxisOffset, const OrderedFlexItemList&, const Vector<LayoutUnit, 16>& childSizes, LayoutUnit availableFreeSpace, bool relayoutChildren, SubtreeLayoutScope&, Vector<LineContext>&);
     void layoutColumnReverse(const OrderedFlexItemList&, LayoutUnit crossAxisOffset, LayoutUnit availableFreeSpace);
     void alignFlexLines(Vector<LineContext>&);
     void alignChildren(const Vector<LineContext>&);
     void applyStretchAlignmentToChild(LayoutBox& child, LayoutUnit lineCrossAxisExtent);
     void flipForRightToLeftColumn();
     void flipForWrapReverse(const Vector<LineContext>&, LayoutUnit crossAxisStartEdge);
 
+    float countIntrinsicSizeForAlgorithmChange(LayoutUnit maxPreferredWidth, LayoutBox* child, float previousMaxContentFlexFraction) const;
+
     // This is used to cache the preferred size for orthogonal flow children so we don't have to relayout to get it
     HashMap<const LayoutObject*, LayoutUnit> m_intrinsicSizeAlongMainAxis;
 
     mutable OrderIterator m_orderIterator;
     int m_numberOfInFlowChildrenOnFirstLine;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutFlexibleBox, isFlexibleBox());
 
 } // namespace blink
 
 #endif // LayoutFlexibleBox_h