ScrollableArea should update scrollAnimator with clamped position.

third_party/WebKit/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 264 matching lines @@
     if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar())
         horizontalScrollbar->offsetDidChange();
     if (Scrollbar* verticalScrollbar = this->verticalScrollbar())
         verticalScrollbar->offsetDidChange();
 
     if (scrollPositionDouble() != oldPosition) {
         // FIXME: Pass in DoubleSize. crbug.com/414283.
         scrollAnimator().notifyContentAreaScrolled(toFloatSize(scrollPositionDouble() - oldPosition));
     }
 
-    scrollAnimator().setCurrentPosition(toFloatPoint(position));
+    scrollAnimator().setCurrentPosition(toFloatPoint(clampScrollPosition(position)));
 }
 
 bool ScrollableArea::scrollBehaviorFromString(const String& behaviorString, ScrollBehavior& behavior)
 {
     if (behaviorString == "auto")
         behavior = ScrollBehaviorAuto;
     else if (behaviorString == "instant")
         behavior = ScrollBehaviorInstant;
     else if (behaviorString == "smooth")
         behavior = ScrollBehaviorSmooth;
@@ skipping 315 matching lines @@
         std::max(0, size.height() - horizontalScrollbarHeight()));
 }
 
 DEFINE_TRACE(ScrollableArea)
 {
     visitor->trace(m_scrollAnimator);
     visitor->trace(m_programmaticScrollAnimator);
 }
 
 } // namespace blink