MainFrame scrollbars should work with RFV instead of FV

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

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
index b5ff43d9e63497e3970144fc3f3c584c8fc61f91..3add25fba605bf95d123cc55193a9a2417217b8c 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -1763,6 +1763,13 @@ PaintLayerScrollableArea::compositorAnimationTimeline() const {
   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());