Make initBatchTracker private, move towards pipeline on batch

src/gpu/GrTargetCommands.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 GrTargetCommands_DEFINED
 #define GrTargetCommands_DEFINED
 
@@ skipping 223 matching lines @@
 
         SkIPoint    fDstPoint;
         SkIRect     fSrcRect;
 
     private:
         GrPendingIOResource<GrSurface, kWrite_GrIOType> fDst;
         GrPendingIOResource<GrSurface, kRead_GrIOType> fSrc;
     };
 
     struct DrawBatch : public Cmd {
-        DrawBatch(State* state, GrBatch* batch, GrBatchTarget* batchTarget)
+        DrawBatch(const State* state, GrBatch* batch, GrBatchTarget* batchTarget)
             : Cmd(kDrawBatch_CmdType)
             , fState(SkRef(state))
             , fBatch(SkRef(batch))
             , fBatchTarget(batchTarget) {
             SkASSERT(!batch->isUsed());
         }
 
         void execute(GrGpu*) override;
 
-        SkAutoTUnref<State>    fState;
-        SkAutoTUnref<GrBatch>  fBatch;
+        SkAutoTUnref<const State>   fState;
+        SkAutoTUnref<GrBatch>       fBatch;
 
     private:
         GrBatchTarget*         fBatchTarget;
     };
 
     struct XferBarrier : public Cmd {
         XferBarrier(GrRenderTarget* rt)
             : Cmd(kXferBarrier_CmdType)
             , fRenderTarget(rt) {
         }
@@ skipping 13 matching lines @@
 
     CmdBuffer* cmdBuffer() { return &fCmdBuffer; }
     GrBatchTarget* batchTarget() { return &fBatchTarget; }
 
     CmdBuffer                           fCmdBuffer;
     GrBatchTarget                       fBatchTarget;
 };
 
 #endif