feat(bigtable/spanner): add google-c2p dependence to bigtable and spanner

bigtable/bigtable_enablexds.go

@@ -0,0 +1,22 @@
+// Copyright 2021 Google LLC
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build enablexds
+// +build enablexds
+
+package bigtable
+
+import (
+	// Install google-c2p resolver, which is required for direct path.
+	_ "google.golang.org/grpc/xds/googledirectpath"
+)

spanner/client_enablexds.go

@@ -0,0 +1,23 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build enablexds
+// +build enablexds
+
+package spanner
+
+import (
+	// Install google-c2p resolver, which is required for direct path.
+	_ "google.golang.org/grpc/xds/googledirectpath"
+)