Reland main thread position sticky implementation.

third_party/WebKit/Source/core/layout/LayoutDeprecatedFlexibleBox.cpp

 /*
  * This file is part of the layout object implementation for KHTML.
  *
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 243 matching lines @@
 
         if (previousSize.height() != size().height())
             relayoutChildren = true;
 
         layoutPositionedObjects(relayoutChildren || isDocumentElement());
 
         computeOverflow(oldClientAfterEdge);
     }
 
     updateLayerTransformAfterLayout();
-    updateScrollInfoAfterLayout();
+    updateAfterLayout();
 
     if (view()->layoutState()->pageLogicalHeight())
         setPageLogicalOffset(view()->layoutState()->pageLogicalOffset(*this, logicalTop()));
 
     clearNeedsLayout();
 }
 
 // The first walk over our kids is to find out if we have any flexible children.
 static void gatherFlexChildrenInfo(FlexBoxIterator& iterator, bool relayoutChildren, unsigned& highestFlexGroup, unsigned& lowestFlexGroup, bool& haveFlex)
 {
@@ skipping 722 matching lines @@
     if (minHeight.isFixed() || minHeight.isAuto()) {
         LayoutUnit minHeight(child->style()->minHeight().value());
         LayoutUnit height = contentHeightForChild(child);
         LayoutUnit allowedShrinkage = (minHeight - height).clampPositiveToZero();
         return allowedShrinkage;
     }
     return LayoutUnit();
 }
 
 } // namespace blink