Put clear and discard into GrBatch.

src/gpu/batches/GrVertexBatch.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 GrVertexBatch_DEFINED
 #define GrVertexBatch_DEFINED
 
 #include "GrDrawBatch.h"
 #include "GrPrimitiveProcessor.h"
 #include "GrPendingProgramElement.h"
 #include "GrVertices.h"
 
 #include "SkTLList.h"
 
 class GrBatchFlushState;
 
 /**
  * Base class for vertex-based GrBatches.
  */
 class GrVertexBatch : public GrDrawBatch {
 public:
     class Target;
 
     GrVertexBatch();
 
-    void prepareDraws(GrBatchFlushState* state);
-    void issueDraws(GrBatchFlushState* state);
-
 protected:
     /** Helper for rendering instances using an instanced index index buffer. This class creates the
         space for the vertices and flushes the draws to the batch target. */
    class InstancedHelper {
    public:
         InstancedHelper() {}
         /** Returns the allocated storage for the vertices. The caller should populate the before
             vertices before calling issueDraws(). */
         void* init(Target*, GrPrimitiveType, size_t vertexStride,
                    const GrIndexBuffer*, int verticesPerInstance, int indicesPerInstance,
@@ skipping 16 matching lines @@
             and on sucess a pointer to the vertex data that the caller should populate before
             calling issueDraws(). */
         void* init(Target* batchTarget, size_t vertexStride, int quadsToDraw);
 
         using InstancedHelper::recordDraw;
     private:
         typedef InstancedHelper INHERITED;
     };
 
 private:
+    void onPrepare(GrBatchFlushState* state) final;
+    void onDraw(GrBatchFlushState* state) final;
+
     virtual void onPrepareDraws(Target*) = 0;
 
     // A set of contiguous draws with no inline uploads between them that all use the same
     // primitive processor. All the draws in a DrawArray share a primitive processor and use the
     // the batch's GrPipeline.
     struct DrawArray {
         SkSTArray<1, GrVertices, true>                      fDraws;
         GrPendingProgramElement<const GrPrimitiveProcessor> fPrimitiveProcessor;
     };
 
     // Array of DrawArray. There may be inline uploads between each DrawArray and each DrawArray
     // may use a different primitive processor.
     SkTLList<DrawArray> fDrawArrays;
 
     // What is this?
     GrBatchTracker      fBatchTracker;
 
     typedef GrDrawBatch INHERITED;
 };
 
 #endif