[CSS Exclusions] Programmatic layout tests fail when subpixel layout is disabled

Source/core/rendering/exclusions/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 13 matching lines @@
  * 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 "core/rendering/exclusions/ExclusionPolygon.h"
 
 #include "core/platform/graphics/LayoutPoint.h"
-
-#include <wtf/MathExtras.h>
+#include "wtf/MathExtras.h"
 
 namespace WebCore {
 
 enum EdgeIntersectionType {
     Normal,
     VertexMinY,
     VertexMaxY,
     VertexYBoth
 };
 
@@ skipping 67 matching lines @@
 static inline void appendArc(Vector<FloatPoint>& vertices, const FloatPoint& arcCenter, float arcRadius, const FloatPoint& startArcVertex, const FloatPoint& endArcVertex, bool padding)
 {
     float startAngle = atan2(startArcVertex.y() - arcCenter.y(), startArcVertex.x() - arcCenter.x());
     float endAngle = atan2(endArcVertex.y() - arcCenter.y(), endArcVertex.x() - arcCenter.x());
     const float twoPI = piFloat * 2;
     if (startAngle < 0)
         startAngle += twoPI;
     if (endAngle < 0)
         endAngle += twoPI;
     float angle = (startAngle > endAngle) ? (startAngle - endAngle) : (startAngle + twoPI - endAngle);
-    const float arcSegmentCount = 5; // An odd number so that one arc vertex will be eactly arcRadius from arcCenter.
-    float angle5 =  ((padding) ? -angle : twoPI - angle) / arcSegmentCount;
+    const float arcSegmentCount = 6; // An even number so that one arc vertex will be eactly arcRadius from arcCenter.
+    float arcSegmentAngle =  ((padding) ? -angle : twoPI - angle) / arcSegmentCount;
 
     vertices.append(startArcVertex);
     for (unsigned i = 1; i < arcSegmentCount; ++i) {
-        float angle = startAngle + angle5 * i;
+        float angle = startAngle + arcSegmentAngle * 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]);
 }
@@ skipping 366 matching lines @@
             }
         }
     }
 
     if (firstFitFound)
         result = LayoutUnit::fromFloatCeil(firstFitRect.y());
     return firstFitFound;
 }
 
 } // namespace WebCore