Fix the bug that negative outline-offset is covered up by composited

third_party/WebKit/Source/core/paint/PaintLayerPaintingInfo.h

Index: third_party/WebKit/Source/core/paint/PaintLayerPaintingInfo.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerPaintingInfo.h b/third_party/WebKit/Source/core/paint/PaintLayerPaintingInfo.h
index dbedc1980c78162fd74812796910eee156d1ec5e..042851c6078bc64a131d414e862b4fbb83903a06 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerPaintingInfo.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayerPaintingInfo.h
@@ -69,10 +69,12 @@ enum PaintLayerFlag {
   PaintLayerPaintingSkipRootBackground = 1 << 10,
   PaintLayerPaintingChildClippingMaskPhase = 1 << 11,
   PaintLayerPaintingRenderingClipPathAsMask = 1 << 12,
+  PaintLayerPaintingCompositingDecorationPhase = 1 << 13,
   PaintLayerPaintingCompositingAllPhases =
       (PaintLayerPaintingCompositingBackgroundPhase |
        PaintLayerPaintingCompositingForegroundPhase |
-       PaintLayerPaintingCompositingMaskPhase)
+       PaintLayerPaintingCompositingMaskPhase |
+       PaintLayerPaintingCompositingDecorationPhase)
 };
 
 typedef unsigned PaintLayerFlags;