change aggregation_ops to internal type
diff --git a/BUILD b/BUILD
index d09a56f..864d735 100644
--- a/BUILD
+++ b/BUILD
@@ -245,6 +245,7 @@
     "src/core/transport/stream_op.h",
     "src/core/transport/transport.h",
     "src/core/transport/transport_impl.h",
+    "src/core/census/aggregation.h",
     "src/core/census/context.h",
     "src/core/census/rpc_metric_id.h",
     "src/core/httpcli/httpcli_security_connector.c",
@@ -514,6 +515,7 @@
     "src/core/transport/stream_op.h",
     "src/core/transport/transport.h",
     "src/core/transport/transport_impl.h",
+    "src/core/census/aggregation.h",
     "src/core/census/context.h",
     "src/core/census/rpc_metric_id.h",
     "src/core/surface/init_unsecure.c",
@@ -1271,6 +1273,7 @@
     "src/core/transport/stream_op.h",
     "src/core/transport/transport.h",
     "src/core/transport/transport_impl.h",
+    "src/core/census/aggregation.h",
     "src/core/census/context.h",
     "src/core/census/rpc_metric_id.h",
   ],