Use threshold of 1 texture coord value per pixel w/ nearest neighbor.

Review URL: https://codereview.chromium.org/787873002
diff --git a/src/gpu/effects/GrSingleTextureEffect.cpp b/src/gpu/effects/GrSingleTextureEffect.cpp
index 3ab5e3a..c291735 100644
--- a/src/gpu/effects/GrSingleTextureEffect.cpp
+++ b/src/gpu/effects/GrSingleTextureEffect.cpp
@@ -10,7 +10,7 @@
 GrSingleTextureEffect::GrSingleTextureEffect(GrTexture* texture,
                                              const SkMatrix& m,
                                              GrCoordSet coordSet)
-    : fCoordTransform(coordSet, m, texture)
+    : fCoordTransform(coordSet, m, texture, GrTextureParams::kNone_FilterMode)
     , fTextureAccess(texture) {
     this->addCoordTransform(&fCoordTransform);
     this->addTextureAccess(&fTextureAccess);
@@ -20,7 +20,7 @@
                                              const SkMatrix& m,
                                              GrTextureParams::FilterMode filterMode,
                                              GrCoordSet coordSet)
-    : fCoordTransform(coordSet, m, texture)
+    : fCoordTransform(coordSet, m, texture, filterMode)
     , fTextureAccess(texture, filterMode) {
     this->addCoordTransform(&fCoordTransform);
     this->addTextureAccess(&fTextureAccess);
@@ -30,7 +30,7 @@
                                              const SkMatrix& m,
                                              const GrTextureParams& params,
                                              GrCoordSet coordSet)
-    : fCoordTransform(coordSet, m, texture)
+    : fCoordTransform(coordSet, m, texture, params.filterMode())
     , fTextureAccess(texture, params) {
     this->addCoordTransform(&fCoordTransform);
     this->addTextureAccess(&fTextureAccess);