Preserve fractional scroll offset for JS scrolling API

Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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
@@ skipping 139 matching lines @@
 
     virtual IntRect windowResizerRect() const override;
 
     virtual float visibleContentScaleFactor() const override { return m_visibleContentScaleFactor; }
     void setVisibleContentScaleFactor(float);
 
     virtual float inputEventsScaleFactor() const override;
     virtual IntSize inputEventsOffsetForEmulation() const override;
     void setInputEventsTransformForEmulation(const IntSize&, float);
 
-    virtual void setScrollPosition(const IntPoint&, ScrollBehavior = ScrollBehaviorInstant) override;
+    virtual void setScrollPosition(const DoublePoint&, ScrollBehavior = ScrollBehaviorInstant) override;
     virtual bool isRubberBandInProgress() const override;
     void setScrollPositionNonProgrammatically(const IntPoint&);
 
     // This is different than visibleContentRect() in that it ignores negative (or overly positive)
     // offsets from rubber-banding, and it takes zooming into account.
     LayoutRect viewportConstrainedVisibleContentRect() const;
     void viewportConstrainedVisibleContentSizeChanged(bool widthChanged, bool heightChanged);
 
     AtomicString mediaType() const;
     void setMediaType(const AtomicString&);
@@ skipping 390 matching lines @@
         m_view->setCanInvalidatePaintDuringPerformLayout(m_originalValue);
     }
 private:
     FrameView* m_view;
     bool m_originalValue;
 };
 
 } // namespace blink
 
 #endif // FrameView_h