Remove calculateStdDeviation function from Blur effect.

Source/platform/graphics/filters/FEGaussianBlur.cpp

Index: Source/platform/graphics/filters/FEGaussianBlur.cpp
diff --git a/Source/platform/graphics/filters/FEGaussianBlur.cpp b/Source/platform/graphics/filters/FEGaussianBlur.cpp
index b2def55b4e613de412d9ef352a41f3e67acc8c5f..631eac48165ff4e7b57d86d0067fbdda7db7d160 100644
--- a/Source/platform/graphics/filters/FEGaussianBlur.cpp
+++ b/Source/platform/graphics/filters/FEGaussianBlur.cpp
@@ -362,10 +362,4 @@ TextStream& FEGaussianBlur::externalRepresentation(TextStream& ts, int indent) c
     return ts;
 }
 
-float FEGaussianBlur::calculateStdDeviation(float radius)
-{
-    // Blur radius represents 2/3 times the kernel size, the dest pixel is half of the radius applied 3 times
-    return max((radius * 2 / 3.f - 0.5f) / gaussianKernelFactor(), 0.f);
-}
-
 } // namespace WebCore