Add constant twoPiDouble/twoPiFloat to MathExtras.h

Source/platform/audio/SincResampler.cpp

 /*
  * Copyright (C) 2011 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.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 101 matching lines @@
         double subsampleOffset = static_cast<double>(offsetIndex) / m_numberOfKernelOffsets;
 
         for (int i = 0; i < n; ++i) {
             // Compute the sinc() with offset.
             double s = sincScaleFactor * piDouble * (i - halfSize - subsampleOffset);
             double sinc = !s ? 1.0 : sin(s) / s;
             sinc *= sincScaleFactor;
 
             // Compute Blackman window, matching the offset of the sinc().
             double x = (i - subsampleOffset) / n;
-            double window = a0 - a1 * cos(2.0 * piDouble * x) + a2 * cos(4.0 * piDouble * x);
+            double window = a0 - a1 * cos(twoPiDouble * x) + a2 * cos(twoPiDouble * 2.0 * x);
 
             // Window the sinc() function and store at the correct offset.
             m_kernelStorage[i + offsetIndex * m_kernelSize] = sinc * window;
         }
     }
 }
 
 void SincResampler::consumeSource(float* buffer, unsigned numberOfSourceFrames)
 {
     ASSERT(m_sourceProvider);
@@ skipping 332 matching lines @@
 
         // Step (4)
         // Refresh the buffer with more input.
         consumeSource(r5, m_blockSize);
     }
 }
 
 } // namespace WebCore
 
 #endif // ENABLE(WEB_AUDIO)