gRPC migration

Change-Id: I3129ae27d7ee12a23c7046f0d877e8064f2fd7f4
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go b/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go
index b1eeea5..c1866f3 100644
--- a/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go
+++ b/vendor/google.golang.org/protobuf/internal/encoding/messageset/messageset.go
@@ -11,10 +11,9 @@
 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/internal/errors"
 	pref "google.golang.org/protobuf/reflect/protoreflect"
-	preg "google.golang.org/protobuf/reflect/protoregistry"
 )
 
-// The MessageSet wire format is equivalent to a message defiend as follows,
+// The MessageSet wire format is equivalent to a message defined as follows,
 // where each Item defines an extension field with a field number of 'type_id'
 // and content of 'message'. MessageSet extensions must be non-repeated message
 // fields.
@@ -48,33 +47,17 @@
 	return ok && xmd.IsMessageSet()
 }
 
-// IsMessageSetExtension reports this field extends a MessageSet.
+// IsMessageSetExtension reports this field properly extends a MessageSet.
 func IsMessageSetExtension(fd pref.FieldDescriptor) bool {
-	if fd.Name() != ExtensionName {
+	switch {
+	case fd.Name() != ExtensionName:
+		return false
+	case !IsMessageSet(fd.ContainingMessage()):
+		return false
+	case fd.FullName().Parent() != fd.Message().FullName():
 		return false
 	}
-	if fd.FullName().Parent() != fd.Message().FullName() {
-		return false
-	}
-	return IsMessageSet(fd.ContainingMessage())
-}
-
-// FindMessageSetExtension locates a MessageSet extension field by name.
-// In text and JSON formats, the extension name used is the message itself.
-// The extension field name is derived by appending ExtensionName.
-func FindMessageSetExtension(r preg.ExtensionTypeResolver, s pref.FullName) (pref.ExtensionType, error) {
-	name := s.Append(ExtensionName)
-	xt, err := r.FindExtensionByName(name)
-	if err != nil {
-		if err == preg.NotFound {
-			return nil, err
-		}
-		return nil, errors.Wrap(err, "%q", name)
-	}
-	if !IsMessageSetExtension(xt.TypeDescriptor()) {
-		return nil, preg.NotFound
-	}
-	return xt, nil
+	return true
 }
 
 // SizeField returns the size of a MessageSet item field containing an extension