Recalc custom scrollbar style.

Source/core/layout/LayoutBox.cpp

Index: Source/core/layout/LayoutBox.cpp
diff --git a/Source/core/layout/LayoutBox.cpp b/Source/core/layout/LayoutBox.cpp
index aff8b7f4339afcf14c19215ae9c50f6b2c768c16..4db3b1211060bcd2331339ed0ae4bfcf8dbd22dc 100644
--- a/Source/core/layout/LayoutBox.cpp
+++ b/Source/core/layout/LayoutBox.cpp
@@ -235,6 +235,14 @@ void LayoutBox::styleDidChange(StyleDifference diff, const ComputedStyle* oldSty
     if (isDocumentElement() || isBody()) {
         document().view()->recalculateScrollbarOverlayStyle();
         document().view()->recalculateCustomScrollbarStyle();
+        if (LayoutView* layoutView = view()) {
+            if (DeprecatedPaintLayerScrollableArea* scrollableArea = layoutView->scrollableArea()) {
+                if (scrollableArea->horizontalScrollbar() && scrollableArea->horizontalScrollbar()->isCustomScrollbar())
+                    scrollableArea->horizontalScrollbar()->styleChanged();
+                if (scrollableArea->verticalScrollbar() && scrollableArea->verticalScrollbar()->isCustomScrollbar())
+                    scrollableArea->verticalScrollbar()->styleChanged();
+            }
+        }
     }
     updateShapeOutsideInfoAfterStyleChange(*style(), oldStyle);
     updateGridPositionAfterStyleChange(oldStyle);