Add option to draw wireframe batch bounds

src/gpu/batches/GrStencilPathBatch.h

Index: src/gpu/batches/GrStencilPathBatch.h
diff --git a/src/gpu/batches/GrStencilPathBatch.h b/src/gpu/batches/GrStencilPathBatch.h
index a0dcadb620eae059bbbe5ad5f21d13b6af3cef1f..33189c2885b9d2c6db3586a29ddc654416953aab 100644
--- a/src/gpu/batches/GrStencilPathBatch.h
+++ b/src/gpu/batches/GrStencilPathBatch.h
@@ -31,6 +31,7 @@ public:
     const char* name() const override { return "StencilPath"; }
 
     uint32_t renderTargetUniqueID() const override { return fRenderTarget.get()->getUniqueID(); }
+    GrRenderTarget* renderTarget() const override { return fRenderTarget.get(); }
 
     SkString dumpInfo() const override {
         SkString string;