Reland main thread position sticky implementation.

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

 /*
  * Copyright (C) 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 386 matching lines @@
 
         if (size() != previousSize)
             relayoutChildren = true;
 
         layoutPositionedObjects(relayoutChildren || isDocumentElement());
 
         computeOverflow(oldClientAfterEdge);
     }
 
     updateLayerTransformAfterLayout();
-    updateScrollInfoAfterLayout();
+    updateAfterLayout();
 
     clearNeedsLayout();
 }
 
 LayoutUnit LayoutGrid::guttersSize(GridTrackSizingDirection direction, size_t span) const
 {
     ASSERT(span >= 1);
 
     if (span == 1)
         return LayoutUnit();
@@ skipping 1701 matching lines @@
 
     return LayoutPoint(rowAxisOffset, columnAxisOffsetForChild(child, sizingData));
 }
 
 void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
 {
     GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
 } // namespace blink