Add option to draw wireframe batch bounds

src/gpu/GrDrawTarget.h

Index: src/gpu/GrDrawTarget.h
diff --git a/src/gpu/GrDrawTarget.h b/src/gpu/GrDrawTarget.h
index 7b0159e5d5833d02d0bb19931eee104b429300b6..dc38b5d6d89e59d6e281802748d5eb81472519f7 100644
--- a/src/gpu/GrDrawTarget.h
+++ b/src/gpu/GrDrawTarget.h
@@ -45,8 +45,9 @@ class GrDrawTarget final : public SkRefCnt {
 public:
     /** Options for GrDrawTarget behavior. */
     struct Options {
-        Options () : fClipBatchToBounds(false) {}
+        Options () : fClipBatchToBounds(false), fDrawBatchBounds(false) {}
         bool fClipBatchToBounds;
+        bool fDrawBatchBounds;
     };
 
     GrDrawTarget(GrRenderTarget*, GrGpu*, GrResourceProvider*, const Options&);
@@ -319,6 +320,8 @@ private:
     SkTDArray<GrDrawTarget*>                    fDependencies;
     GrRenderTarget*                             fRenderTarget;
 
+    bool                                        fDrawBatchBounds;
+
     typedef SkRefCnt INHERITED;
 };