[SPInvalidation] Fix PrePaintTreeWalk for multicol spanner

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

Index: third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
diff --git a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
index 5ab77f578257e1cfa1cd2c42b59496b6f022f541..1bec1d9bf4cfd2242012e8d61cf061a423b10aab 100644
--- a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
+++ b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.h
@@ -71,6 +71,8 @@ struct PaintPropertyTreeBuilderContext {
   // Therefore, we don't need extra bookkeeping for effect nodes and can
   // generate the effect tree from a DOM-order traversal.
   const EffectPaintPropertyNode* currentEffect = nullptr;
+
+  bool isUnderMultiColumnSpanner = false;
 };
 
 // Creates paint property tree nodes for special things in the layout tree.