Fix scrollbar damage accumulation issue

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 052e0aa3c0c2db3ff6961f0c9a125a5eec6405b8..ddb82d4bb8005178be439e4618d2a7420a411344 100644
--- a/Source/core/rendering/RenderLayerScrollableArea.cpp
+++ b/Source/core/rendering/RenderLayerScrollableArea.cpp
@@ -205,18 +205,10 @@ void RenderLayerScrollableArea::invalidateScrollbarRect(Scrollbar* scrollbar, co
 
     IntRect intRect = pixelSnappedIntRect(repaintRect);
 
-    if (box().frameView()->isInPerformLayout()) {
-        if (scrollbar == m_vBar.get()) {
-            m_verticalBarDamage = intRect;
-            m_hasVerticalBarDamage = true;
-        } else {
-            m_horizontalBarDamage = intRect;
-            m_hasHorizontalBarDamage = true;
-        }
-
-    } else {
+    if (box().frameView()->isInPerformLayout())
+        addScrollbarDamage(scrollbar, intRect);
+    else
         box().invalidatePaintRectangle(intRect);
-    }
 }
 
 void RenderLayerScrollableArea::invalidateScrollCornerRect(const IntRect& rect)