| Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp | 
| diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp | 
| index da5c63fe309570da68daae860020acb42a61f502..afe7b98de06f1f8ccd22b661e37e2e8d193f3b3f 100644 | 
| --- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp | 
| +++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp | 
| @@ -2466,6 +2466,13 @@ bool PaintLayer::shouldBeSelfPaintingLayer() const | 
| || needsCompositedScrolling(); | 
| } | 
|  | 
| +bool PaintLayer::shouldPaintBackgroundOntoForeground() const | 
| +{ | 
| +    return scrollsOverflow() | 
| +        && layoutObject()->style()->hasEntirelyLocalBackground() | 
| +        && !stackingNode()->hasNegativeZOrderList(); | 
| +} | 
| + | 
| void PaintLayer::updateSelfPaintingLayer() | 
| { | 
| bool isSelfPaintingLayer = shouldBeSelfPaintingLayer(); | 
|  |