add a ClassID function to GrBatch

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 22 matching lines @@
     GrBatchToken fLastUploadToken;
 };
 
 /**
  * Base class for GrBatches that draw. These batches have a GrPipeline installed by GrDrawTarget.
  */
 class GrDrawBatch : public GrBatch {
 public:
     class Target;
 
-    GrDrawBatch();
+    GrDrawBatch(uint32_t classID);
     ~GrDrawBatch() override;
 
     virtual void getInvariantOutputColor(GrInitInvariantOutput* out) const = 0;
     virtual void getInvariantOutputCoverage(GrInitInvariantOutput* out) const = 0;
 
     const GrPipeline* pipeline() const {
         SkASSERT(fPipelineInstalled);
         return reinterpret_cast<const GrPipeline*>(fPipelineStorage.get());
     }
 
@@ skipping 31 matching lines @@
 protected:
     SkTArray<SkAutoTUnref<GrBatchUploader>, true>   fInlineUploads;
 
 private:
     SkAlignedSTStorage<1, GrPipeline>               fPipelineStorage;
     bool                                            fPipelineInstalled;
     typedef GrBatch INHERITED;
 };
 
 #endif