[VOL-4289]  Proto changes for gRPC migration

Change-Id: I317a0a865ccf78d0c37aa229c50d293a3f66c8bb
diff --git a/vendor/google.golang.org/grpc/internal/internal.go b/vendor/google.golang.org/grpc/internal/internal.go
new file mode 100644
index 0000000..1b596bf
--- /dev/null
+++ b/vendor/google.golang.org/grpc/internal/internal.go
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2016 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 internal contains gRPC-internal code, to avoid polluting
+// the godoc of the top-level grpc package.  It must not import any grpc
+// symbols to avoid circular dependencies.
+package internal
+
+import (
+	"context"
+	"time"
+
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/serviceconfig"
+)
+
+var (
+	// WithHealthCheckFunc is set by dialoptions.go
+	WithHealthCheckFunc interface{} // func (HealthChecker) DialOption
+	// HealthCheckFunc is used to provide client-side LB channel health checking
+	HealthCheckFunc HealthChecker
+	// BalancerUnregister is exported by package balancer to unregister a balancer.
+	BalancerUnregister func(name string)
+	// KeepaliveMinPingTime is the minimum ping interval.  This must be 10s by
+	// default, but tests may wish to set it lower for convenience.
+	KeepaliveMinPingTime = 10 * time.Second
+	// ParseServiceConfigForTesting is for creating a fake
+	// ClientConn for resolver testing only
+	ParseServiceConfigForTesting interface{} // func(string) *serviceconfig.ParseResult
+	// EqualServiceConfigForTesting is for testing service config generation and
+	// parsing. Both a and b should be returned by ParseServiceConfigForTesting.
+	// This function compares the config without rawJSON stripped, in case the
+	// there's difference in white space.
+	EqualServiceConfigForTesting func(a, b serviceconfig.Config) bool
+	// GetCertificateProviderBuilder returns the registered builder for the
+	// given name. This is set by package certprovider for use from xDS
+	// bootstrap code while parsing certificate provider configs in the
+	// bootstrap file.
+	GetCertificateProviderBuilder interface{} // func(string) certprovider.Builder
+	// GetXDSHandshakeInfoForTesting returns a pointer to the xds.HandshakeInfo
+	// stored in the passed in attributes. This is set by
+	// credentials/xds/xds.go.
+	GetXDSHandshakeInfoForTesting interface{} // func (*attributes.Attributes) *xds.HandshakeInfo
+	// GetServerCredentials returns the transport credentials configured on a
+	// gRPC server. An xDS-enabled server needs to know what type of credentials
+	// is configured on the underlying gRPC server. This is set by server.go.
+	GetServerCredentials interface{} // func (*grpc.Server) credentials.TransportCredentials
+	// DrainServerTransports initiates a graceful close of existing connections
+	// on a gRPC server accepted on the provided listener address. An
+	// xDS-enabled server invokes this method on a grpc.Server when a particular
+	// listener moves to "not-serving" mode.
+	DrainServerTransports interface{} // func(*grpc.Server, string)
+)
+
+// HealthChecker defines the signature of the client-side LB channel health checking function.
+//
+// The implementation is expected to create a health checking RPC stream by
+// calling newStream(), watch for the health status of serviceName, and report
+// it's health back by calling setConnectivityState().
+//
+// The health checking protocol is defined at:
+// https://github.com/grpc/grpc/blob/master/doc/health-checking.md
+type HealthChecker func(ctx context.Context, newStream func(string) (interface{}, error), setConnectivityState func(connectivity.State, error), serviceName string) error
+
+const (
+	// CredsBundleModeFallback switches GoogleDefaultCreds to fallback mode.
+	CredsBundleModeFallback = "fallback"
+	// CredsBundleModeBalancer switches GoogleDefaultCreds to grpclb balancer
+	// mode.
+	CredsBundleModeBalancer = "balancer"
+	// CredsBundleModeBackendFromBalancer switches GoogleDefaultCreds to mode
+	// that supports backend returned by grpclb balancer.
+	CredsBundleModeBackendFromBalancer = "backend-from-balancer"
+)