Implement CSSOM Smooth Scroll API

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index 2121d1a946c53f25d05165c4322b36185294988e..b05408b249deb6d7953b38aa4a6145a6e608ed7d 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -398,23 +398,23 @@ int RenderBox::pixelSnappedScrollHeight() const
     return snapSizeToPixel(scrollHeight(), y() + clientTop());
 }
 
-void RenderBox::setScrollLeft(LayoutUnit newLeft)
+void RenderBox::setScrollLeft(LayoutUnit newLeft, ScrollBehavior scrollBehavior)
 {
     // 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, scrollBehavior);
 }
 
-void RenderBox::setScrollTop(LayoutUnit newTop)
+void RenderBox::setScrollTop(LayoutUnit newTop, ScrollBehavior scrollBehavior)
 {
     // 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, scrollBehavior);
 }
 
 void RenderBox::scrollToOffset(const IntSize& offset)