Use float for scroll offset.

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 434 matching lines @@
 
   LayoutUnit remainingSpace;
 
   FlexBoxIterator iterator(this);
   unsigned highestFlexGroup = 0;
   unsigned lowestFlexGroup = 0;
   bool haveFlex = false, flexingChildren = false;
   gatherFlexChildrenInfo(iterator, relayoutChildren, highestFlexGroup,
                          lowestFlexGroup, haveFlex);
 
-  PaintLayerScrollableArea::DelayScrollPositionClampScope delayClampScope;
+  PaintLayerScrollableArea::DelayScrollOffsetClampScope delayClampScope;
 
   // We do 2 passes.  The first pass is simply to lay everyone out at
   // their preferred widths.  The second pass handles flexing the children.
   do {
     // Reset our height.
     setHeight(yPos);
 
     xPos = borderLeft() + paddingLeft();
 
     // Our first pass is done without flexing.  We simply lay the children
@@ skipping 314 matching lines @@
   bool haveFlex = false, flexingChildren = false;
   gatherFlexChildrenInfo(iterator, relayoutChildren, highestFlexGroup,
                          lowestFlexGroup, haveFlex);
 
   // We confine the line clamp ugliness to vertical flexible boxes (thus keeping it out of
   // mainstream block layout); this is not really part of the XUL box model.
   bool haveLineClamp = !style()->lineClamp().isNone();
   if (haveLineClamp)
     applyLineClamp(iterator, relayoutChildren);
 
-  PaintLayerScrollableArea::DelayScrollPositionClampScope delayClampScope;
+  PaintLayerScrollableArea::DelayScrollOffsetClampScope delayClampScope;
 
   // We do 2 passes.  The first pass is simply to lay everyone out at
   // their preferred widths.  The second pass handles flexing the children.
   // Our first pass is done without flexing.  We simply lay the children
   // out within the box.
   do {
     setHeight(borderTop() + paddingTop());
     LayoutUnit minHeight = size().height() + toAdd;
 
     for (LayoutBox* child = iterator.first(); child; child = iterator.next()) {
@@ skipping 431 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