Issue trace events to gather repaint information.

Source/core/rendering/RenderLayerScrollableArea.cpp

Index: Source/core/rendering/RenderLayerScrollableArea.cpp
diff --git a/Source/core/rendering/RenderLayerScrollableArea.cpp b/Source/core/rendering/RenderLayerScrollableArea.cpp
index f853c269513d06935c90b40684118bb58a9ec078..2974651368daf825cdef56d0d2be1858ff20e09f 100644
--- a/Source/core/rendering/RenderLayerScrollableArea.cpp
+++ b/Source/core/rendering/RenderLayerScrollableArea.cpp
@@ -408,9 +408,9 @@ void RenderLayerScrollableArea::setScrollOffset(const IntPoint& newScrollOffset)
             if (m_box->frameView()->isInPerformLayout())
                 m_box->setShouldDoFullRepaintAfterLayout(true);
             else
-                m_box->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(layer()->renderer()->newRepaintRect()));
+                m_box->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(layer()->renderer()->newRepaintRect()), InvalidationScroll);
         } else {
-            m_box->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(layer()->repainter().repaintRect()));
+            m_box->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(layer()->repainter().repaintRect()), InvalidationScroll);
         }
     }