Reland "Stack-allocate pipelines for GrMeshDrawOp"

This is a reland of dfe5000a5ff2cabb50ddc139882dc1f3005fa429

Original change's description:
> Stack-allocate pipelines for GrMeshDrawOp
>
> Stack-allocates the pipelines in onExecute. This saves us from having
> to store the pipelines on the heap, as well as delaying the need to
> detach processors until onExecute. The delay is an improvement because
> it allows us to keep visiting proxies after onPrepare. (Previously,
> they were moved out of GrProcessorSet and into a pipeline during
> onPrepare, so visiting proxies was impossible after that point.)
>
> Bug: skia:8731
> Change-Id: Idc05063fb0dfbfed42b434e429fa5a497097bdae
> Reviewed-on: https://skia-review.googlesource.com/c/193368
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

TBR=robertphillips@google.com

Bug: skia:8731
Change-Id: I32def1a35bb0593470fa672691a9e697dc6d9680
Reviewed-on: https://skia-review.googlesource.com/c/195261
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/ops/GrShadowRRectOp.cpp b/src/gpu/ops/GrShadowRRectOp.cpp
index 0d99501..8cb87d6 100644
--- a/src/gpu/ops/GrShadowRRectOp.cpp
+++ b/src/gpu/ops/GrShadowRRectOp.cpp
@@ -589,15 +589,16 @@
             }
         }
 
-        static const uint32_t kPipelineFlags = 0;
-        auto pipe = target->makePipeline(kPipelineFlags, GrProcessorSet::MakeEmptySet(),
-                                         target->detachAppliedClip());
-
         GrMesh* mesh = target->allocMesh(GrPrimitiveType::kTriangles);
         mesh->setIndexed(std::move(indexBuffer), fIndexCount, firstIndex, 0, fVertCount - 1,
                          GrPrimitiveRestart::kNo);
         mesh->setVertexData(std::move(vertexBuffer), firstVertex);
-        target->draw(std::move(gp), pipe.fPipeline, pipe.fFixedDynamicState, mesh);
+        target->recordDraw(std::move(gp), mesh);
+    }
+
+    void onExecute(GrOpFlushState* flushState, const SkRect& chainBounds) override {
+        flushState->executeDrawsAndUploadsForMeshDrawOp(
+                this, chainBounds, GrProcessorSet::MakeEmptySet());
     }
 
     CombineResult onCombineIfPossible(GrOp* t, const GrCaps& caps) override {