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

Source/core/rendering/ExclusionPolygon.cpp

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 11 matching lines @@
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "ExclusionPolygon.h"
+#include "LayoutPoint.h"
 
 #include <wtf/MathExtras.h>
 
 namespace WebCore {
 
 enum EdgeIntersectionType {
     Normal,
     VertexMinY,
     VertexMaxY,
     VertexYBoth
@@ skipping 80 matching lines @@
     float angle5 =  ((padding) ? -angle : twoPI - angle) / arcSegmentCount;
 
     vertices.append(startArcVertex);
     for (unsigned i = 1; i < arcSegmentCount; ++i) {
         float angle = startAngle + angle5 * i;
         vertices.append(arcCenter + FloatPoint(cos(angle) * arcRadius, sin(angle) * arcRadius));
     }
     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>();
     FloatPoint intersection;
 
     for (unsigned i = 0; i < polygon.numberOfEdges(); ++i) {
         const FloatPolygonEdge& thisEdge = polygon.edgeAt(i);
         const FloatPolygonEdge& prevEdge = thisEdge.previousEdge();
         OffsetPolygonEdge thisOffsetEdge(thisEdge, inwardEdgeNormal(thisEdge) * padding);
         OffsetPolygonEdge prevOffsetEdge(prevEdge, inwardEdgeNormal(prevEdge) * padding);
 
         if (prevOffsetEdge.intersection(thisOffsetEdge, intersection))
             paddedVertices->append(intersection);
         else if (isReflexVertex(prevEdge.vertex1(), thisEdge.vertex1(), thisEdge.vertex2()))
             appendArc(*paddedVertices, thisEdge.vertex1(), padding, prevOffsetEdge.vertex2(), thisOffsetEdge.vertex1(), true);
     }
 
+    snapVerticesToLayoutUnitGrid(*paddedVertices);
     return new FloatPolygon(adoptPtr(paddedVertices), fillRule);
 }
 
 static inline FloatPolygon* computeShapeMarginBounds(const FloatPolygon& polygon, float margin, WindRule fillRule)
 {
     Vector<FloatPoint>* marginVertices = new Vector<FloatPoint>();
     FloatPoint intersection;
 
     for (unsigned i = 0; i < polygon.numberOfEdges(); ++i) {
         const FloatPolygonEdge& thisEdge = polygon.edgeAt(i);
         const FloatPolygonEdge& prevEdge = thisEdge.previousEdge();
         OffsetPolygonEdge thisOffsetEdge(thisEdge, outwardEdgeNormal(thisEdge) * margin);
         OffsetPolygonEdge prevOffsetEdge(prevEdge, outwardEdgeNormal(prevEdge) * margin);
 
         if (prevOffsetEdge.intersection(thisOffsetEdge, intersection))
             marginVertices->append(intersection);
         else
             appendArc(*marginVertices, thisEdge.vertex1(), margin, prevOffsetEdge.vertex2(), thisOffsetEdge.vertex1(), false);
     }
 
+    snapVerticesToLayoutUnitGrid(*marginVertices);
     return new FloatPolygon(adoptPtr(marginVertices), fillRule);
 }
 
 const FloatPolygon& ExclusionPolygon::shapePaddingBounds() const
 {
     ASSERT(shapePadding() >= 0);
     if (!shapePadding())
         return m_polygon;
 
     if (!m_paddingBounds)
@@ skipping 310 matching lines @@
             }
         }
     }
 
     if (firstFitFound)
         result = firstFitRect.y();
     return firstFitFound;
 }
 
 } // namespace WebCore