switch patheffects over to sk_sp

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1813553005

Review URL: https://codereview.chromium.org/1813553005
diff --git a/src/effects/SkLayerDrawLooper.cpp b/src/effects/SkLayerDrawLooper.cpp
index bca65ef..83f21e5 100644
--- a/src/effects/SkLayerDrawLooper.cpp
+++ b/src/effects/SkLayerDrawLooper.cpp
@@ -93,7 +93,7 @@
     }
 
     if (bits & kPathEffect_Bit) {
-        dst->setPathEffect(src.getPathEffect());
+        dst->setPathEffect(sk_ref_sp(src.getPathEffect()));
     }
     if (bits & kMaskFilter_Bit) {
         dst->setMaskFilter(src.getMaskFilter());