Hook up window.scrollTo and friends.

Source/platform/scroll/ScrollableArea.h

 /*
  * Copyright (C) 2008, 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 47 matching lines @@
 public:
     static int pixelsPerLineStep();
     static float minFractionToStepWhenPaging();
     static int maxOverlapBetweenPages();
 
     // The window that hosts the ScrollableArea. The ScrollableArea will communicate scrolls and repaints to the
     // host window in the window's coordinate space.
     virtual HostWindow* hostWindow() const { return 0; };
 
     bool scroll(ScrollDirection, ScrollGranularity, float delta = 1);
+    virtual void setScrollPosition(const DoublePoint&, ScrollBehavior = ScrollBehaviorInstant);
     void scrollToOffsetWithoutAnimation(const FloatPoint&, bool cancelProgrammaticAnimations = true);
     void scrollToOffsetWithoutAnimation(ScrollbarOrientation, float offset);
 
     void programmaticallyScrollSmoothlyToOffset(const FloatPoint&);
 
     // Should be called when the scroll position changes externally, for example if the scroll layer position
     // is updated on the scrolling thread and we need to notify the main thread.
     void notifyScrollPositionChanged(const DoublePoint&);
 
     static bool scrollBehaviorFromString(const String&, ScrollBehavior&);
@@ skipping 246 matching lines @@
     // vertical-lr / ltr            NO                      NO
     // vertical-lr / rtl            NO                      YES
     // vertical-rl / ltr            YES                     NO
     // vertical-rl / rtl            YES                     YES
     IntPoint m_scrollOrigin;
 };
 
 } // namespace blink
 
 #endif // ScrollableArea_h