[CSS Exclusions] Zoom causes shape-inside to fail when shape-padding is specified

Source/core/rendering/ExclusionPolygon.cpp

Index: Source/core/rendering/ExclusionPolygon.cpp
diff --git a/Source/core/rendering/ExclusionPolygon.cpp b/Source/core/rendering/ExclusionPolygon.cpp
index 136287ac40f54a90d70754c8defa857add7cc4cd..b3d5884bfcd2575d1501391c5141357e0b1bdd03 100644
--- a/Source/core/rendering/ExclusionPolygon.cpp
+++ b/Source/core/rendering/ExclusionPolygon.cpp
@@ -29,6 +29,7 @@
 
 #include "config.h"
 #include "ExclusionPolygon.h"
+#include "LayoutPoint.h"
 
 #include <wtf/MathExtras.h>
 
@@ -129,6 +130,12 @@ static inline void appendArc(Vector<FloatPoint>& vertices, const FloatPoint& arc
     vertices.append(endArcVertex);
 }
 
+static inline void snapVerticesToLayoutUnitGrid(Vector<FloatPoint>& vertices)
+{
+    for (unsigned i = 0; i < vertices.size(); ++i)
+      vertices[i] = flooredLayoutPoint(vertices[i]);
+}
+
 static inline FloatPolygon* computeShapePaddingBounds(const FloatPolygon& polygon, float padding, WindRule fillRule)
 {
     Vector<FloatPoint>* paddedVertices = new Vector<FloatPoint>();
@@ -146,6 +153,7 @@ static inline FloatPolygon* computeShapePaddingBounds(const FloatPolygon& polygo
             appendArc(*paddedVertices, thisEdge.vertex1(), padding, prevOffsetEdge.vertex2(), thisOffsetEdge.vertex1(), true);
     }
 
+    snapVerticesToLayoutUnitGrid(*paddedVertices);
     return new FloatPolygon(adoptPtr(paddedVertices), fillRule);
 }
 
@@ -166,6 +174,7 @@ static inline FloatPolygon* computeShapeMarginBounds(const FloatPolygon& polygon
             appendArc(*marginVertices, thisEdge.vertex1(), margin, prevOffsetEdge.vertex2(), thisOffsetEdge.vertex1(), false);
     }
 
+    snapVerticesToLayoutUnitGrid(*marginVertices);
     return new FloatPolygon(adoptPtr(marginVertices), fillRule);
 }