Add metadata_map.h to build.yaml
Add missing files to BUILD
diff --git a/BUILD b/BUILD
index d065060..0200b14 100644
--- a/BUILD
+++ b/BUILD
@@ -1183,6 +1183,7 @@
         "include/grpc++/impl/codegen/core_codegen_interface.h",
         "include/grpc++/impl/codegen/create_auth_context.h",
         "include/grpc++/impl/codegen/grpc_library.h",
+        "include/grpc++/impl/codegen/metadata_map.h",
         "include/grpc++/impl/codegen/method_handler_impl.h",
         "include/grpc++/impl/codegen/rpc_method.h",
         "include/grpc++/impl/codegen/rpc_service_method.h",
@@ -1191,6 +1192,7 @@
         "include/grpc++/impl/codegen/server_context.h",
         "include/grpc++/impl/codegen/server_interface.h",
         "include/grpc++/impl/codegen/service_type.h",
+        "include/grpc++/impl/codegen/slice.h",
         "include/grpc++/impl/codegen/status.h",
         "include/grpc++/impl/codegen/status_code_enum.h",
         "include/grpc++/impl/codegen/status_helper.h",