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/DeviceTest.cpp b/tests/DeviceTest.cpp
index f7d855a..34140a7 100644
--- a/tests/DeviceTest.cpp
+++ b/tests/DeviceTest.cpp
@@ -38,7 +38,7 @@
 
     SkImageInfo ii = SkImageInfo::MakeN32Premul(2*kWidth, 2*kHeight);
 
-    SkAutoTUnref<SkBaseDevice> bmDev(SkBitmapDevice::Create(ii));
+    sk_sp<SkBaseDevice> bmDev(SkBitmapDevice::Create(ii));
 
     SkBitmap bm;
     bm.tryAllocN32Pixels(kWidth, kHeight);