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

src/gpu/batches/GrDrawVerticesBatch.h

Index: src/gpu/batches/GrDrawVerticesBatch.h
diff --git a/src/gpu/batches/GrDrawVerticesBatch.h b/src/gpu/batches/GrDrawVerticesBatch.h
index 9446d88bde0f7e3c6b2d54b81b4ac136c827e6ad..11decbe01db5ec9fc69ce49af4d5ce1ca21c2667 100644
--- a/src/gpu/batches/GrDrawVerticesBatch.h
+++ b/src/gpu/batches/GrDrawVerticesBatch.h
@@ -18,7 +18,7 @@
 class GrBatchTarget;
 struct GrInitInvariantOutput;
 
-class GrDrawVerticesBatch : public GrBatch {
+class GrDrawVerticesBatch : public GrVertexBatch {
 public:
     struct Geometry {
         GrColor fColor;
@@ -28,12 +28,12 @@ public:
         SkTDArray<SkPoint> fLocalCoords;
     };
 
-    static GrBatch* Create(const Geometry& geometry, GrPrimitiveType primitiveType,
-                           const SkMatrix& viewMatrix,
-                           const SkPoint* positions, int vertexCount,
-                           const uint16_t* indices, int indexCount,
-                           const GrColor* colors, const SkPoint* localCoords,
-                           const SkRect& bounds) {
+    static GrDrawBatch* Create(const Geometry& geometry, GrPrimitiveType primitiveType,
+                               const SkMatrix& viewMatrix,
+                               const SkPoint* positions, int vertexCount,
+                               const uint16_t* indices, int indexCount,
+                               const GrColor* colors, const SkPoint* localCoords,
+                               const SkRect& bounds) {
         return SkNEW_ARGS(GrDrawVerticesBatch, (geometry, primitiveType, viewMatrix, positions,
                                                 vertexCount, indices, indexCount, colors,
                                                 localCoords, bounds));