Revert of Consolidate GPU buffer implementations

src/gpu/batches/GrTInstanceBatch.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 GrTInstanceBatch_DEFINED
 #define GrTInstanceBatch_DEFINED
 
@@ skipping 16 matching lines @@
  *     void SetBounds(const Geometry& seedGeometry, SkRect* outBounds)
  *
  *     void UpdateBoundsAfterAppend(const Geometry& lastGeometry, SkRect* currentBounds)
  *
  *     bool CanCombine(const Geometry& mine, const Geometry& theirs,
  *                     const GrXPOverridesForBatch&)
  *
  *     const GrGeometryProcessor* CreateGP(const Geometry& seedGeometry,
  *                                         const GrXPOverridesForBatch& overrides)
  *
- *     const GrBuffer* GetIndexBuffer(GrResourceProvider*)
+ *     const GrIndexBuffer* GetIndexBuffer(GrResourceProvider*)
  *
  *     Tesselate(intptr_t vertices, size_t vertexStride, const Geometry& geo,
  *               const GrXPOverridesForBatch& overrides)
  */
 template <typename Impl>
 class GrTInstanceBatch : public GrVertexBatch {
 public:
     DEFINE_BATCH_CLASS_ID
 
     typedef typename Impl::Geometry Geometry;
@@ skipping 46 matching lines @@
         if (!gp) {
             SkDebugf("Couldn't create GrGeometryProcessor\n");
             return;
         }
 
         target->initDraw(gp);
 
         size_t vertexStride = gp->getVertexStride();
         int instanceCount = fGeoData.count();
 
-        SkAutoTUnref<const GrBuffer> indexBuffer(
+        SkAutoTUnref<const GrIndexBuffer> indexBuffer(
                 Impl::GetIndexBuffer(target->resourceProvider()));
         InstancedHelper helper;
         void* vertices = helper.init(target, kTriangles_GrPrimitiveType, vertexStride,
                                      indexBuffer, Impl::kVertsPerInstance,
                                      Impl::kIndicesPerInstance, instanceCount);
         if (!vertices || !indexBuffer) {
             SkDebugf("Could not allocate vertices\n");
             return;
         }
 
@@ skipping 29 matching lines @@
         return true;
     }
 
     GrXPOverridesForBatch fOverrides;
     SkSTArray<1, Geometry, true> fGeoData;
 
     typedef GrVertexBatch INHERITED;
 };
 
 #endif