Hook up window.scrollTo and friends.

Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 141 matching lines @@
         step = pixelStep(orientation);
         break;
     }
 
     if (direction == ScrollUp || direction == ScrollLeft)
         delta = -delta;
 
     return scrollAnimator()->scroll(orientation, granularity, step, delta);
 }
 
+void ScrollableArea::setScrollPosition(const DoublePoint& position, ScrollBehavior behavior)
+{
+    // FIXME(417782): This should be unified with RenderLayerScrollableArea::scrollToOffset.
+    ASSERT_NOT_REACHED();
+}
+
 void ScrollableArea::scrollToOffsetWithoutAnimation(const FloatPoint& offset, bool cancelProgrammaticAnimations)
 {
     if (cancelProgrammaticAnimations)
         cancelProgrammaticScrollAnimation();
     scrollAnimator()->scrollToOffsetWithoutAnimation(offset);
 }
 
 void ScrollableArea::scrollToOffsetWithoutAnimation(ScrollbarOrientation orientation, float offset)
 {
     if (orientation == HorizontalScrollbar)
@@ skipping 339 matching lines @@
 {
     return scrollSize(orientation);
 }
 
 float ScrollableArea::pixelStep(ScrollbarOrientation) const
 {
     return 1;
 }
 
 } // namespace blink