add API for Op creation

Introduce three calls on GrOp: Make, MakeWithExtraMemory,
and MakeWithProcessorSet. Instead of returning
unique_ptr<GrOp>, they return a type of GrOp::OpOwner.
GrOp::OpOwner safely deletes the op when it goes out
of scope for either new/delete or GrOpMemoryPool
allocations.

In order to make the code easier to refactor, I
eliminated MakeArg from the helpers.

Change-Id: Icfd697906f3147a8734575d08bd7195e7517383a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/323778
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Herb Derby <herb@google.com>
diff --git a/src/gpu/ops/GrDrawableOp.cpp b/src/gpu/ops/GrDrawableOp.cpp
index a8ba547..4756606 100644
--- a/src/gpu/ops/GrDrawableOp.cpp
+++ b/src/gpu/ops/GrDrawableOp.cpp
@@ -14,11 +14,10 @@
 #include "src/gpu/GrOpsRenderPass.h"
 #include "src/gpu/GrRecordingContextPriv.h"
 
-std::unique_ptr<GrDrawableOp> GrDrawableOp::Make(
+GrOp::Owner GrDrawableOp::Make(
         GrRecordingContext* context, std::unique_ptr<SkDrawable::GpuDrawHandler> drawable,
         const SkRect& bounds) {
-    GrOpMemoryPool* pool = context->priv().opMemoryPool();
-    return pool->allocate<GrDrawableOp>(std::move(drawable), bounds);
+    return GrOp::Make<GrDrawableOp>(context, std::move(drawable), bounds);
 }
 
 GrDrawableOp::GrDrawableOp(std::unique_ptr<SkDrawable::GpuDrawHandler> drawable,