gRPC migration

Change-Id: I3129ae27d7ee12a23c7046f0d877e8064f2fd7f4
diff --git a/vendor/github.com/golang/protobuf/ptypes/timestamp.go b/vendor/github.com/golang/protobuf/ptypes/timestamp.go
index 026d0d4..8368a3f 100644
--- a/vendor/github.com/golang/protobuf/ptypes/timestamp.go
+++ b/vendor/github.com/golang/protobuf/ptypes/timestamp.go
@@ -33,6 +33,8 @@
 //
 // A nil Timestamp returns an error. The first return value in that case is
 // undefined.
+//
+// Deprecated: Call the ts.AsTime and ts.CheckValid methods instead.
 func Timestamp(ts *timestamppb.Timestamp) (time.Time, error) {
 	// Don't return the zero value on error, because corresponds to a valid
 	// timestamp. Instead return whatever time.Unix gives us.
@@ -46,6 +48,8 @@
 }
 
 // TimestampNow returns a google.protobuf.Timestamp for the current time.
+//
+// Deprecated: Call the timestamppb.Now function instead.
 func TimestampNow() *timestamppb.Timestamp {
 	ts, err := TimestampProto(time.Now())
 	if err != nil {
@@ -56,6 +60,8 @@
 
 // TimestampProto converts the time.Time to a google.protobuf.Timestamp proto.
 // It returns an error if the resulting Timestamp is invalid.
+//
+// Deprecated: Call the timestamppb.New function instead.
 func TimestampProto(t time.Time) (*timestamppb.Timestamp, error) {
 	ts := &timestamppb.Timestamp{
 		Seconds: t.Unix(),
@@ -69,6 +75,9 @@
 
 // TimestampString returns the RFC 3339 string for valid Timestamps.
 // For invalid Timestamps, it returns an error message in parentheses.
+//
+// Deprecated: Call the ts.AsTime method instead,
+// followed by a call to the Format method on the time.Time value.
 func TimestampString(ts *timestamppb.Timestamp) string {
 	t, err := Timestamp(ts)
 	if err != nil {