Introduce GrBatch subclasses GrDrawBatch and GrVertexBatch to prepare for non-drawing batches

src/gpu/batches/GrAAFillRectBatch.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 GrAAFillRectBatch_DEFINED
 #define GrAAFillRectBatch_DEFINED
 
 #include "GrColor.h"
 
-class GrBatch;
+class GrDrawBatch;
 class SkMatrix;
 struct SkRect;
 
 namespace GrAAFillRectBatch {
-GrBatch* Create(GrColor color,
-                const SkMatrix& viewMatrix,
-                const SkRect& rect,
-                const SkRect& devRect);
+GrDrawBatch* Create(GrColor color,
+                    const SkMatrix& viewMatrix,
+                    const SkRect& rect,
+                    const SkRect& devRect);
 
-GrBatch* Create(GrColor color,
-                const SkMatrix& viewMatrix,
-                const SkMatrix& localMatrix,
-                const SkRect& rect,
-                const SkRect& devRect);
+GrDrawBatch* Create(GrColor color,
+                    const SkMatrix& viewMatrix,
+                    const SkMatrix& localMatrix,
+                    const SkRect& rect,
+                    const SkRect& devRect);
 };
 
 #endif