Add constant twoPiDouble/twoPiFloat to MathExtras.h

Source/core/rendering/shapes/PolygonShape.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 96 matching lines @@
 
 static inline FloatSize outwardEdgeNormal(const FloatPolygonEdge& edge)
 {
     return -inwardEdgeNormal(edge);
 }
 
 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;
+        startAngle += twoPiFloat;
     if (endAngle < 0)
-        endAngle += twoPI;
-    float angle = (startAngle > endAngle) ? (startAngle - endAngle) : (startAngle + twoPI - endAngle);
+        endAngle += twoPiFloat;
+    float angle = (startAngle > endAngle) ? (startAngle - endAngle) : (startAngle + twoPiFloat - endAngle);
     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;
+    float arcSegmentAngle =  ((padding) ? -angle : twoPiFloat - angle) / arcSegmentCount;
 
     vertices.append(startArcVertex);
     for (unsigned i = 1; i < arcSegmentCount; ++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)
@@ skipping 387 matching lines @@
             }
         }
     }
 
     if (firstFitFound)
         result = LayoutUnit::fromFloatCeil(firstFitRect.y());
     return firstFitFound;
 }
 
 } // namespace WebCore