switch unique_ptr with deleter to GrMemoryPool

I switched GrOps from using GrOpMemoryPool to
GrMemoryPool, but I forgot to switch over the
GrOp::Owner. Make sure the GrOp::Owner works for
both new/delete and GrMemoryPool.

In addition, convert one last unique_ptr<GrOp> to
GrOp::Owner.

Change-Id: I660ad77bee0f060f263ff2ed07974afb83063441
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/330097
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/src/gpu/GrPathRendering_none.cpp b/src/gpu/GrPathRendering_none.cpp
index 048e8a3..9e73eda 100644
--- a/src/gpu/GrPathRendering_none.cpp
+++ b/src/gpu/GrPathRendering_none.cpp
@@ -46,11 +46,11 @@
 
 void GrGLPathRendering::onStencilPath(const StencilPathArgs&, const GrPath*) {}
 
-std::unique_ptr<GrOp> GrStencilPathOp::Make(GrRecordingContext*,
-                                            const SkMatrix&,
-                                            bool,
-                                            bool,
-                                            const GrScissorState&,
-                                            sk_sp<const GrPath>) { return nullptr; }
+GrOp::Owner GrStencilPathOp::Make(GrRecordingContext*,
+                                  const SkMatrix&,
+                                  bool,
+                                  bool,
+                                  const GrScissorState&,
+                                  sk_sp<const GrPath>) { return nullptr; }
 
 void GrPath::ComputeKey(const GrStyledShape&, GrUniqueKey*, bool*) {}