Move MakeDivByTextureWHMatrix to GrCoordTransform

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/522873005
diff --git a/src/gpu/effects/GrMatrixConvolutionEffect.cpp b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
index e573996..b78c637 100644
--- a/src/gpu/effects/GrMatrixConvolutionEffect.cpp
+++ b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
@@ -157,7 +157,7 @@
                                                      const SkIPoint& kernelOffset,
                                                      GrTextureDomain::Mode tileMode,
                                                      bool convolveAlpha)
-  : INHERITED(texture, MakeDivByTextureWHMatrix(texture)),
+  : INHERITED(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture)),
     fKernelSize(kernelSize),
     fGain(SkScalarToFloat(gain)),
     fBias(SkScalarToFloat(bias) / 255.0f),