Highlighting on UAOS - alternate approach

Source/core/rendering/compositing/CompositedLayerMapping.cpp

Index: Source/core/rendering/compositing/CompositedLayerMapping.cpp
diff --git a/Source/core/rendering/compositing/CompositedLayerMapping.cpp b/Source/core/rendering/compositing/CompositedLayerMapping.cpp
index 3f3eeb5bc620195b3bcd7e04d5f38dbf2058e7f6..e109d9435e44b204b73215c9fe2cfe7eb52d7a83 100644
--- a/Source/core/rendering/compositing/CompositedLayerMapping.cpp
+++ b/Source/core/rendering/compositing/CompositedLayerMapping.cpp
@@ -1061,7 +1061,7 @@ void CompositedLayerMapping::updateDrawsContent()
         bool hasNonScrollingPaintedContent = m_owningLayer.hasVisibleContent() && m_owningLayer.hasBoxDecorationsOrBackground();
         m_graphicsLayer->setDrawsContent(hasNonScrollingPaintedContent);
 
-        bool hasScrollingPaintedContent = m_owningLayer.hasVisibleContent() && (renderer()->hasBackground() || paintsChildren());
+        bool hasScrollingPaintedContent = m_owningLayer.hasVisibleContent() && (renderer()->hasBackground() || paintsChildren() || hasScrollChildren());
         m_scrollingContentsLayer->setDrawsContent(hasScrollingPaintedContent);
         return;
     }
@@ -1482,6 +1482,14 @@ void CompositedLayerMapping::updateScrollParent(RenderLayer* scrollParent)
     }
 }
 
+bool CompositedLayerMapping::hasScrollChildren()
+{
+    ScrollingCoordinator* scrollingCoordinator = scrollingCoordinatorFromLayer(m_owningLayer);
+    if (!scrollingCoordinator)
+        return false;
+    return scrollingCoordinator->hasScrollChildren(parentForSublayers());
+}
+
 void CompositedLayerMapping::updateClipParent(RenderLayer* clipParent)
 {
     if (ScrollingCoordinator* scrollingCoordinator = scrollingCoordinatorFromLayer(m_owningLayer))