Add constant twoPiDouble/twoPiFloat to MathExtras.h

Source/platform/transforms/AffineTransform.cpp

 /*
  * Copyright (C) 2005, 2006 Apple Computer, Inc.  All rights reserved.
  *               2010 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2013 Google Inc. 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 304 matching lines @@
     this->decompose(srB);
 
     // If x-axis of one is flipped, and y-axis of the other, convert to an unflipped rotation.
     if ((srA.scaleX < 0 && srB.scaleY < 0) || (srA.scaleY < 0 &&  srB.scaleX < 0)) {
         srA.scaleX = -srA.scaleX;
         srA.scaleY = -srA.scaleY;
         srA.angle += srA.angle < 0 ? piDouble : -piDouble;
     }
 
     // Don't rotate the long way around.
-    srA.angle = fmod(srA.angle, 2 * piDouble);
-    srB.angle = fmod(srB.angle, 2 * piDouble);
+    srA.angle = fmod(srA.angle, twoPiDouble);
+    srB.angle = fmod(srB.angle, twoPiDouble);
 
     if (fabs(srA.angle - srB.angle) > piDouble) {
         if (srA.angle > srB.angle)
-            srA.angle -= piDouble * 2;
+            srA.angle -= twoPiDouble;
         else
-            srB.angle -= piDouble * 2;
+            srB.angle -= twoPiDouble;
     }
 
     srA.scaleX += progress * (srB.scaleX - srA.scaleX);
     srA.scaleY += progress * (srB.scaleY - srA.scaleY);
     srA.angle += progress * (srB.angle - srA.angle);
     srA.remainderA += progress * (srB.remainderA - srA.remainderA);
     srA.remainderB += progress * (srB.remainderB - srA.remainderB);
     srA.remainderC += progress * (srB.remainderC - srA.remainderC);
     srA.remainderD += progress * (srB.remainderD - srA.remainderD);
     srA.translateX += progress * (srB.translateX - srA.translateX);
@@ skipping 55 matching lines @@
     this->setB(decomp.remainderB);
     this->setC(decomp.remainderC);
     this->setD(decomp.remainderD);
     this->setE(decomp.translateX);
     this->setF(decomp.translateY);
     this->rotateRadians(decomp.angle);
     this->scale(decomp.scaleX, decomp.scaleY);
 }
 
 }