Hook up window.scrollTo and friends.

Source/core/rendering/RenderLayerScrollableArea.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 118 matching lines @@
     void scrollToXOffset(double x, ScrollOffsetClamping clamp = ScrollOffsetUnclamped, ScrollBehavior scrollBehavior = ScrollBehaviorInstant)
     {
         scrollToOffset(DoubleSize(x, scrollYOffset()), clamp, scrollBehavior);
     }
 
     void scrollToYOffset(double y, ScrollOffsetClamping clamp = ScrollOffsetUnclamped, ScrollBehavior scrollBehavior = ScrollBehaviorInstant)
     {
         scrollToOffset(DoubleSize(scrollXOffset(), y), clamp, scrollBehavior);
     }
 
+    virtual void setScrollPosition(const DoublePoint& position, ScrollBehavior scrollBehavior = ScrollBehaviorInstant) override
+    {
+        scrollToOffset(toDoubleSize(position), ScrollOffsetClamped, scrollBehavior);
+    }
+
     void updateAfterLayout();
     void updateAfterStyleChange(const RenderStyle*);
     void updateAfterOverflowRecalc();
 
     virtual bool updateAfterCompositingChange() override;
 
     bool hasScrollbar() const { return m_hBar || m_vBar; }
 
     RenderScrollbarPart* scrollCorner() const { return m_scrollCorner; }
 
@@ skipping 126 matching lines @@
     // Renderers to hold our custom scroll corner.
     RawPtrWillBePersistent<RenderScrollbarPart> m_scrollCorner;
 
     // Renderers to hold our custom resizer.
     RawPtrWillBePersistent<RenderScrollbarPart> m_resizer;
 };
 
 } // namespace blink
 
 #endif // RenderLayerScrollableArea_h