MainFrame scrollbars should work with RFV instead of FV

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@gmail.com>
@@ skipping 1745 matching lines @@
 PaintLayerScrollableArea::compositorAnimationTimeline() const {
   if (LocalFrame* frame = box().frame()) {
     if (Page* page = frame->page())
       return page->scrollingCoordinator()
                  ? page->scrollingCoordinator()->compositorAnimationTimeline()
                  : nullptr;
   }
   return nullptr;
 }
 
+void PaintLayerScrollableArea::getTickmarks(Vector<IntRect>& tickmarks) const {
+  // TODO(crbug.com/417782): Verify that tickmarks work with root layer
+  // scrolling.
+  if (LocalFrame* frame = box().frame())

[skobes, 2016/11/10 21:10:47]

I think you also need to check isRootLayer() here?

[ymalik, 2016/11/10 21:22:48]

Yes. Done.

+    frame->view()->getTickmarks(tickmarks);
+}
+
 PaintLayerScrollableArea*
 PaintLayerScrollableArea::ScrollbarManager::scrollableArea() {
   return toPaintLayerScrollableArea(m_scrollableArea.get());
 }
 
 void PaintLayerScrollableArea::ScrollbarManager::destroyDetachedScrollbars() {
   DCHECK(!m_hBarIsAttached || m_hBar);
   DCHECK(!m_vBarIsAttached || m_vBar);
   if (m_hBar && !m_hBarIsAttached)
     destroyScrollbar(HorizontalScrollbar);
@@ skipping 196 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     clampScrollableAreas() {
   for (auto& scrollableArea : *s_needsClamp)
     scrollableArea->clampScrollOffsetsAfterLayout();
   delete s_needsClamp;
   s_needsClamp = nullptr;
 }
 
 }  // namespace blink