First programmatic smooth scroll should run on the compositor if it can

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 416 matching lines @@
 {
     return frame().contentLayoutObject();
 }
 
 ScrollingCoordinator* FrameView::scrollingCoordinator() const
 {
     Page* p = page();
     return p ? p->scrollingCoordinator() : 0;
 }
 
+CompositorAnimationTimeline* FrameView::compositorAnimationTimeline() const
+{
+    ScrollingCoordinator* c = scrollingCoordinator();
+    return c ? c->compositorAnimationTimeline() : nullptr;
+}
+
 void FrameView::setCanHaveScrollbars(bool canHaveScrollbars)
 {
     m_canHaveScrollbars = canHaveScrollbars;
 
     ScrollbarMode newVerticalMode = m_verticalScrollbarMode;
     if (canHaveScrollbars && m_verticalScrollbarMode == ScrollbarAlwaysOff)
         newVerticalMode = ScrollbarAuto;
     else if (!canHaveScrollbars)
         newVerticalMode = ScrollbarAlwaysOff;
 
@@ skipping 3663 matching lines @@
     return m_hiddenForThrottling && m_crossOriginForThrottling;
 }
 
 LayoutBox& FrameView::boxForScrollControlPaintInvalidation() const
 {
     ASSERT(layoutView());
     return *layoutView();
 }
 
 } // namespace blink