Add option to draw wireframe batch bounds

src/gpu/batches/GrDrawBatch.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 GrDrawBatch_DEFINED
 #define GrDrawBatch_DEFINED
 
@@ skipping 45 matching lines @@
     bool installPipeline(const GrPipeline::CreateArgs&);
 
     // TODO no GrPrimitiveProcessors yet read fragment position
     bool willReadFragmentPosition() const { return false; }
 
     uint32_t renderTargetUniqueID() const final {
         SkASSERT(fPipelineInstalled);
         return this->pipeline()->getRenderTarget()->getUniqueID();
     }
 
+    GrRenderTarget* renderTarget() const final {
+        SkASSERT(fPipelineInstalled);
+        return this->pipeline()->getRenderTarget();
+    }
+
     SkString dumpInfo() const override {
         SkString string;
         string.appendf("RT: %d\n", this->renderTargetUniqueID());
         string.append("ColorStages:\n");
         for (int i = 0; i < this->pipeline()->numColorFragmentProcessors(); i++) {
             string.appendf("\t\t%s\n\t\t%s\n",
                            this->pipeline()->getColorFragmentProcessor(i).name(),
                            this->pipeline()->getColorFragmentProcessor(i).dumpInfo().c_str());
         }
         string.append("CoverageStages:\n");
@@ skipping 21 matching lines @@
 protected:
     SkTArray<SkAutoTUnref<GrBatchUploader>, true>   fInlineUploads;
 
 private:
     SkAlignedSTStorage<1, GrPipeline>               fPipelineStorage;
     bool                                            fPipelineInstalled;
     typedef GrBatch INHERITED;
 };
 
 #endif