Add option to draw wireframe batch bounds

src/gpu/batches/GrCopySurfaceBatch.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrCopySurfaceBatch_DEFINED
 #define GrCopySurfaceBatch_DEFINED
 
 #include "GrBatch.h"
 #include "GrBatchFlushState.h"
 #include "GrGpu.h"
 #include "GrRenderTarget.h"
 
 class GrCopySurfaceBatch final : public GrBatch {
 public:
     DEFINE_BATCH_CLASS_ID
 
     static GrBatch* Create(GrSurface* dst, GrSurface* src, const SkIRect& srcRect,
                            const SkIPoint& dstPoint);
 
     const char* name() const override { return "CopySurface"; }
 
     uint32_t renderTargetUniqueID() const override {
         GrRenderTarget* rt = fDst.get()->asRenderTarget();
         return rt ? rt->getUniqueID() : 0;
     }
+    GrRenderTarget* renderTarget() const override { return fDst.get()->asRenderTarget(); }
 
     SkString dumpInfo() const override {
         SkString string;
         string.printf("SRC: 0x%p, DST: 0x%p, SRECT: [L: %d, T: %d, R: %d, B: %d], "
                       "DPT:[X: %d, Y: %d]",
                       fDst.get(), fSrc.get(), fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight,
                       fSrcRect.fBottom, fDstPoint.fX, fDstPoint.fY);
         return string;
     }
 
@@ skipping 19 matching lines @@
 
     GrPendingIOResource<GrSurface, kWrite_GrIOType> fDst;
     GrPendingIOResource<GrSurface, kRead_GrIOType>  fSrc;
     SkIRect                                         fSrcRect;
     SkIPoint                                        fDstPoint;
 
     typedef GrBatch INHERITED;
 };
 
 #endif