Compute better reference/visual boxes for clip-path in columns

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

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 c54063a419d1dd7696bc27caf6e66a2f34bb4f68..fb04f00fb7eda09f5d235ec6bf7698e9f6c6b2cb 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -2076,10 +2076,11 @@ bool PaintLayer::hitTestClippedOutByClipPath(PaintLayer* rootLayer, const HitTes
     DCHECK(isSelfPaintingLayer());
     DCHECK(rootLayer);
 
-    LayoutPoint offsetToRootLayer;
-    convertToLayerCoords(rootLayer, offsetToRootLayer);
     LayoutRect referenceBox(boxForClipPath());
-    referenceBox.moveBy(offsetToRootLayer);
+    if (enclosingPaginationLayer())
+        convertFromFlowThreadToVisualBoundingBoxInAncestor(rootLayer, referenceBox);
+    else
+        convertToLayerCoords(rootLayer, referenceBox);
 
     FloatPoint point(hitTestLocation.point());
 
@@ -2100,7 +2101,7 @@ bool PaintLayer::hitTestClippedOutByClipPath(PaintLayer* rootLayer, const HitTes
     // the coordinate system is the top-left of the reference box, so adjust
     // the point accordingly.
     if (clipper->clipPathUnits() == SVGUnitTypes::kSvgUnitTypeUserspaceonuse)
-        point.moveBy(-offsetToRootLayer);
+        point.moveBy(-referenceBox.location());
     return !clipper->hitTestClipContent(FloatRect(referenceBox), point);
 }