Consolidate GPU buffer implementations

src/gpu/batches/GrDrawVerticesBatch.cpp

Index: src/gpu/batches/GrDrawVerticesBatch.cpp
diff --git a/src/gpu/batches/GrDrawVerticesBatch.cpp b/src/gpu/batches/GrDrawVerticesBatch.cpp
index c76ba7d1ec2ff181504946b3ed4559c0cc327021..20d9f7929067fe1da9b2e6460d17a7f5483a4137 100644
--- a/src/gpu/batches/GrDrawVerticesBatch.cpp
+++ b/src/gpu/batches/GrDrawVerticesBatch.cpp
@@ -106,7 +106,7 @@ void GrDrawVerticesBatch::onPrepareDraws(Target* target) const {
 
     int instanceCount = fGeoData.count();
 
-    const GrVertexBuffer* vertexBuffer;
+    const GrBuffer* vertexBuffer;
     int firstVertex;
 
     void* verts = target->makeVertexSpace(vertexStride, fVertexCount, &vertexBuffer, &firstVertex);
@@ -116,7 +116,7 @@ void GrDrawVerticesBatch::onPrepareDraws(Target* target) const {
         return;
     }
 
-    const GrIndexBuffer* indexBuffer = nullptr;
+    const GrBuffer* indexBuffer = nullptr;
     int firstIndex = 0;
 
     uint16_t* indices = nullptr;