Respect the smooth scrolling setting in LayerScrollableArea.

Source/core/layout/LayerScrollableArea.cpp

Index: Source/core/layout/LayerScrollableArea.cpp
diff --git a/Source/core/layout/LayerScrollableArea.cpp b/Source/core/layout/LayerScrollableArea.cpp
index 44f874f309ad6a9bcaf31b50d2d43a52bd3f1c9a..9a22335fc1334ee04b7103ec7ec1fe2e8039bd8b 100644
--- a/Source/core/layout/LayerScrollableArea.cpp
+++ b/Source/core/layout/LayerScrollableArea.cpp
@@ -488,6 +488,13 @@ IntPoint LayerScrollableArea::lastKnownMousePosition() const
     return box().frame() ? box().frame()->eventHandler().lastKnownMousePosition() : IntPoint();
 }
 
+bool LayerScrollableArea::scrollAnimatorEnabled() const
+{
+    if (Settings* settings = box().frame()->settings())
+        return settings->scrollAnimatorEnabled();
+    return false;
+}
+
 bool LayerScrollableArea::shouldSuspendScrollAnimations() const
 {
     RenderView* view = box().view();