Paint solid color and local attachment backgrounds into scrolling layer.

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

Index: third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
index 3b685597d828d7be414c0362dd314c82aad40ff1..1381adeaca4a440db59eec7fb43b70a3bd353e28 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp
@@ -35,6 +35,8 @@
 
 namespace blink {
 
+namespace {
+
 static inline bool shouldSuppressPaintingLayer(const PaintLayer& layer)
 {
     // Avoid painting descendants of the root layer when stylesheets haven't loaded. This avoids some FOUC.
@@ -47,6 +49,8 @@ static inline bool shouldSuppressPaintingLayer(const PaintLayer& layer)
     return false;
 }
 
+} // namespace
+
 void PaintLayerPainter::paint(GraphicsContext& context, const LayoutRect& damageRect, const GlobalPaintFlags globalPaintFlags, PaintLayerFlags paintFlags)
 {
     PaintLayerPaintingInfo paintingInfo(&m_paintLayer, LayoutRect(enclosingIntRect(damageRect)), globalPaintFlags, LayoutSize());
@@ -381,7 +385,10 @@ PaintLayerPainter::PaintResult PaintLayerPainter::paintLayerContents(GraphicsCon
             scopedPaintChunkProperties.emplace(context.getPaintController(), m_paintLayer, properties);
         }
 
-        bool shouldPaintBackground = isPaintingCompositedBackground && shouldPaintContent && !selectionOnly;
+        bool paintBackgroundOnForeground = isPaintingScrollingContent && m_paintLayer.shouldPaintBackgroundOntoForeground();
+        bool shouldPaintBackground = shouldPaintContent && !selectionOnly
+            && ((paintBackgroundOnForeground && isPaintingCompositedForeground)
+                || isPaintingCompositedBackground);
         bool shouldPaintNegZOrderList = (isPaintingScrollingContent && isPaintingOverflowContents) || (!isPaintingScrollingContent && isPaintingCompositedBackground);
         bool shouldPaintOwnContents = isPaintingCompositedForeground && shouldPaintContent;
         bool shouldPaintNormalFlowAndPosZOrderLists = isPaintingCompositedForeground;