MainFrame scrollbars should work with RFV instead of FV

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

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
index 7aefff29abf49721b30570ab40baa1e7a725eb7c..188dba66171f81e7f7dc38254eb177f4cc560dda 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.h
@@ -293,6 +293,7 @@ class CORE_EXPORT PaintLayerScrollableArea final
   int pageStep(ScrollbarOrientation) const override;
   ScrollBehavior scrollBehaviorStyle() const override;
   CompositorAnimationTimeline* compositorAnimationTimeline() const override;
+  void getTickmarks(Vector<IntRect>& rects) const override;
 
   // FIXME: We shouldn't allow access to m_overflowRect outside this class.
   LayoutRect overflowRect() const { return m_overflowRect; }
@@ -334,6 +335,8 @@ class CORE_EXPORT PaintLayerScrollableArea final
     return hasScrollbar() || scrollCorner() || resizer();
   }
 
+  void updateScrollbars() override;
+
   LayoutScrollbarPart* scrollCorner() const override { return m_scrollCorner; }
 
   void resize(const PlatformEvent&, const LayoutSize&);