[VOL-4289]  Proto changes for gRPC migration

Change-Id: I317a0a865ccf78d0c37aa229c50d293a3f66c8bb
diff --git a/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go b/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go
new file mode 100644
index 0000000..73a2f92
--- /dev/null
+++ b/vendor/google.golang.org/grpc/serviceconfig/serviceconfig.go
@@ -0,0 +1,44 @@
+/*
+ *
+ * Copyright 2019 gRPC authors.
+ *
+ * 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.
+ *
+ */
+
+// Package serviceconfig defines types and methods for operating on gRPC
+// service configs.
+//
+// Experimental
+//
+// Notice: This package is EXPERIMENTAL and may be changed or removed in a
+// later release.
+package serviceconfig
+
+// Config represents an opaque data structure holding a service config.
+type Config interface {
+	isServiceConfig()
+}
+
+// LoadBalancingConfig represents an opaque data structure holding a load
+// balancing config.
+type LoadBalancingConfig interface {
+	isLoadBalancingConfig()
+}
+
+// ParseResult contains a service config or an error.  Exactly one must be
+// non-nil.
+type ParseResult struct {
+	Config Config
+	Err    error
+}