Preserve fractional scroll offset for JS scrolling API

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 258 matching lines @@
     // scrolling).
     virtual LayoutUnit scrollLeft() const;
     virtual LayoutUnit scrollTop() const;
     virtual LayoutUnit scrollWidth() const;
     virtual LayoutUnit scrollHeight() const;
     int pixelSnappedScrollWidth() const;
     int pixelSnappedScrollHeight() const;
     virtual void setScrollLeft(LayoutUnit);
     virtual void setScrollTop(LayoutUnit);
 
-    void scrollToOffset(const IntSize&);
-    void scrollByRecursively(const IntSize& delta, ScrollOffsetClamping = ScrollOffsetUnclamped);
+    void scrollToOffset(const DoubleSize&);
+    void scrollByRecursively(const DoubleSize& delta, ScrollOffsetClamping = ScrollOffsetUnclamped);
     void scrollRectToVisible(const LayoutRect&, const ScrollAlignment& alignX, const ScrollAlignment& alignY);
 
     virtual LayoutUnit marginTop() const OVERRIDE { return m_marginBox.top(); }
     virtual LayoutUnit marginBottom() const OVERRIDE { return m_marginBox.bottom(); }
     virtual LayoutUnit marginLeft() const OVERRIDE { return m_marginBox.left(); }
     virtual LayoutUnit marginRight() const OVERRIDE { return m_marginBox.right(); }
     void setMarginTop(LayoutUnit margin) { m_marginBox.setTop(margin); }
     void setMarginBottom(LayoutUnit margin) { m_marginBox.setBottom(margin); }
     void setMarginLeft(LayoutUnit margin) { m_marginBox.setLeft(margin); }
     void setMarginRight(LayoutUnit margin) { m_marginBox.setRight(margin); }
@@ skipping 490 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // RenderBox_h