Implement CSSOM smooth scroll for Elements

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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 384 matching lines @@
     return snapSizeToPixel(scrollHeight(), location().y() + clientTop());
 }
 
 void RenderBox::setScrollLeft(LayoutUnit newLeft)
 {
     // This doesn't hit in any tests, but since the equivalent code in setScrollTop
     // does, presumably this code does as well.
     DisableCompositingQueryAsserts disabler;
 
     if (hasOverflowClip())
-        layer()->scrollableArea()->scrollToXOffset(newLeft, ScrollOffsetClamped);
+        layer()->scrollableArea()->scrollToXOffset(newLeft, ScrollOffsetClamped, ScrollBehaviorAuto);
 }
 
 void RenderBox::setScrollTop(LayoutUnit newTop)
 {
     // Hits in compositing/overflow/do-not-assert-on-invisible-composited-layers.html
     DisableCompositingQueryAsserts disabler;
 
     if (hasOverflowClip())
-        layer()->scrollableArea()->scrollToYOffset(newTop, ScrollOffsetClamped);
+        layer()->scrollableArea()->scrollToYOffset(newTop, ScrollOffsetClamped, ScrollBehaviorAuto);
 }
 
-void RenderBox::scrollToOffset(const DoubleSize& offset)
+void RenderBox::scrollToOffset(const DoubleSize& offset, ScrollBehavior scrollBehavior)
 {
     ASSERT(hasOverflowClip());
 
     // This doesn't hit in any tests, but since the equivalent code in setScrollTop
     // does, presumably this code does as well.
     DisableCompositingQueryAsserts disabler;
-    layer()->scrollableArea()->scrollToOffset(offset, ScrollOffsetClamped);
+    layer()->scrollableArea()->scrollToOffset(offset, ScrollOffsetClamped, scrollBehavior);
 }
 
 static inline bool frameElementAndViewPermitScroll(HTMLFrameElementBase* frameElementBase, FrameView* frameView)
 {
     // If scrollbars aren't explicitly forbidden, permit scrolling.
     if (frameElementBase && frameElementBase->scrollingMode() != ScrollbarAlwaysOff)
         return true;
 
     // If scrollbars are forbidden, user initiated scrolls should obviously be ignored.
     if (frameView->wasScrolledByUser())
@@ skipping 4057 matching lines @@
     computedValues.m_margins.m_end = marginEnd();
 
     setLogicalTop(oldLogicalTop);
     setLogicalWidth(oldLogicalWidth);
     setLogicalLeft(oldLogicalLeft);
     setMarginLeft(oldMarginLeft);
     setMarginRight(oldMarginRight);
 }
 
 } // namespace blink