[VOL-4289]  Proto changes for gRPC migration

Change-Id: I317a0a865ccf78d0c37aa229c50d293a3f66c8bb
diff --git a/vendor/google.golang.org/grpc/status/status.go b/vendor/google.golang.org/grpc/status/status.go
new file mode 100644
index 0000000..54d1871
--- /dev/null
+++ b/vendor/google.golang.org/grpc/status/status.go
@@ -0,0 +1,129 @@
+/*
+ *
+ * Copyright 2017 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 status implements errors returned by gRPC.  These errors are
+// serialized and transmitted on the wire between server and client, and allow
+// for additional data to be transmitted via the Details field in the status
+// proto.  gRPC service handlers should return an error created by this
+// package, and gRPC clients should expect a corresponding error to be
+// returned from the RPC call.
+//
+// This package upholds the invariants that a non-nil error may not
+// contain an OK code, and an OK code must result in a nil error.
+package status
+
+import (
+	"context"
+	"fmt"
+
+	spb "google.golang.org/genproto/googleapis/rpc/status"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/internal/status"
+)
+
+// Status references google.golang.org/grpc/internal/status. It represents an
+// RPC status code, message, and details.  It is immutable and should be
+// created with New, Newf, or FromProto.
+// https://godoc.org/google.golang.org/grpc/internal/status
+type Status = status.Status
+
+// New returns a Status representing c and msg.
+func New(c codes.Code, msg string) *Status {
+	return status.New(c, msg)
+}
+
+// Newf returns New(c, fmt.Sprintf(format, a...)).
+func Newf(c codes.Code, format string, a ...interface{}) *Status {
+	return New(c, fmt.Sprintf(format, a...))
+}
+
+// Error returns an error representing c and msg.  If c is OK, returns nil.
+func Error(c codes.Code, msg string) error {
+	return New(c, msg).Err()
+}
+
+// Errorf returns Error(c, fmt.Sprintf(format, a...)).
+func Errorf(c codes.Code, format string, a ...interface{}) error {
+	return Error(c, fmt.Sprintf(format, a...))
+}
+
+// ErrorProto returns an error representing s.  If s.Code is OK, returns nil.
+func ErrorProto(s *spb.Status) error {
+	return FromProto(s).Err()
+}
+
+// FromProto returns a Status representing s.
+func FromProto(s *spb.Status) *Status {
+	return status.FromProto(s)
+}
+
+// FromError returns a Status representing err if it was produced by this
+// package or has a method `GRPCStatus() *Status`.
+// If err is nil, a Status is returned with codes.OK and no message.
+// Otherwise, ok is false and a Status is returned with codes.Unknown and
+// the original error message.
+func FromError(err error) (s *Status, ok bool) {
+	if err == nil {
+		return nil, true
+	}
+	if se, ok := err.(interface {
+		GRPCStatus() *Status
+	}); ok {
+		return se.GRPCStatus(), true
+	}
+	return New(codes.Unknown, err.Error()), false
+}
+
+// Convert is a convenience function which removes the need to handle the
+// boolean return value from FromError.
+func Convert(err error) *Status {
+	s, _ := FromError(err)
+	return s
+}
+
+// Code returns the Code of the error if it is a Status error, codes.OK if err
+// is nil, or codes.Unknown otherwise.
+func Code(err error) codes.Code {
+	// Don't use FromError to avoid allocation of OK status.
+	if err == nil {
+		return codes.OK
+	}
+	if se, ok := err.(interface {
+		GRPCStatus() *Status
+	}); ok {
+		return se.GRPCStatus().Code()
+	}
+	return codes.Unknown
+}
+
+// FromContextError converts a context error into a Status.  It returns a
+// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
+// non-nil and not a context error.
+func FromContextError(err error) *Status {
+	switch err {
+	case nil:
+		return nil
+	case context.DeadlineExceeded:
+		return New(codes.DeadlineExceeded, err.Error())
+	case context.Canceled:
+		return New(codes.Canceled, err.Error())
+	default:
+		return New(codes.Unknown, err.Error())
+	}
+}