Move MakeDivByTextureWHMatrix to GrCoordTransform

R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/522873005
diff --git a/src/effects/SkXfermodeImageFilter.cpp b/src/effects/SkXfermodeImageFilter.cpp
index 88ea3f8..98936f7 100644
--- a/src/effects/SkXfermodeImageFilter.cpp
+++ b/src/effects/SkXfermodeImageFilter.cpp
@@ -154,7 +154,7 @@
         return false;
     }
 
-    SkMatrix foregroundMatrix = GrEffect::MakeDivByTextureWHMatrix(foregroundTex);
+    SkMatrix foregroundMatrix = GrCoordTransform::MakeDivByTextureWHMatrix(foregroundTex);
     foregroundMatrix.preTranslate(SkIntToScalar(backgroundOffset.fX-foregroundOffset.fX),
                                   SkIntToScalar(backgroundOffset.fY-foregroundOffset.fY));