guard rasterizer and drawlooper setters

Need to land https://codereview.chromium.org/1823513002/ first

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1821533002

Review URL: https://codereview.chromium.org/1821533002
diff --git a/bench/RectoriBench.cpp b/bench/RectoriBench.cpp
index 1f4da86..e2a44e3 100644
--- a/bench/RectoriBench.cpp
+++ b/bench/RectoriBench.cpp
@@ -52,7 +52,7 @@
             SkScalar translate = 2.0f * size;
 
             SkPaint paint;
-            paint.setLooper(this->createLooper(-translate, blurSigma))->unref();
+            paint.setLooper(this->createLooper(-translate, blurSigma));
             paint.setColor(0xff000000 | Random.nextU());
             paint.setAntiAlias(true);
 
@@ -71,7 +71,7 @@
         H = 480,
     };
 
-    SkLayerDrawLooper* createLooper(SkScalar xOff, SkScalar sigma) {
+    sk_sp<SkDrawLooper> createLooper(SkScalar xOff, SkScalar sigma) {
         SkLayerDrawLooper::Builder looperBuilder;
 
         //-----------------------------------------------
@@ -96,7 +96,7 @@
         info.fOffset.set(0, 0);
 
         paint = looperBuilder.addLayer(info);
-        return looperBuilder.detachLooper();
+        return looperBuilder.detach();
     }
 
     typedef Benchmark INHERITED;