tests: s/SkAutoTUnref/sk_sp/

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4394

Change-Id: I088b3c6e2adff07abed1e8a50091cc0ec4a4109c
Reviewed-on: https://skia-review.googlesource.com/4394
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/tests/GradientTest.cpp b/tests/GradientTest.cpp
index 1e8f393..ee776e3 100644
--- a/tests/GradientTest.cpp
+++ b/tests/GradientTest.cpp
@@ -73,7 +73,7 @@
 }
 
 static void color_gradproc(skiatest::Reporter* reporter, const GradRec& rec, const GradRec&) {
-    SkAutoTUnref<SkShader> s(new SkColorShader(rec.fColors[0]));
+    sk_sp<SkShader> s(new SkColorShader(rec.fColors[0]));
     REPORTER_ASSERT(reporter, SkShader::kColor_GradientType == s->asAGradient(nullptr));
 
     SkShader::GradientInfo info;