Collapse the protobuf extension file into codec factory

The separation is now unneeded.

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/BUILD

@@ -32,7 +32,6 @@ go_library(
     srcs = [
         "codec_factory.go",
         "negotiated_codec.go",
-        "protobuf_extension.go",
     ],
     importmap = "k8s.io/kubernetes/vendor/k8s.io/apimachinery/pkg/runtime/serializer",
     importpath = "k8s.io/apimachinery/pkg/runtime/serializer",

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/codec_factory.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/runtime/serializer/json"
+	"k8s.io/apimachinery/pkg/runtime/serializer/protobuf"
 	"k8s.io/apimachinery/pkg/runtime/serializer/recognizer"
 	"k8s.io/apimachinery/pkg/runtime/serializer/versioning"
 )
@@ -51,6 +52,8 @@ func newSerializersForScheme(scheme *runtime.Scheme, mf json.MetaFactory) []seri
 	jsonSerializer := json.NewSerializer(mf, scheme, scheme, false)
 	jsonPrettySerializer := json.NewSerializer(mf, scheme, scheme, true)
 	yamlSerializer := json.NewYAMLSerializer(mf, scheme, scheme)
+	serializer := protobuf.NewSerializer(scheme, scheme, runtime.ContentTypeProtobuf)
+	raw := protobuf.NewRawSerializer(scheme, scheme, runtime.ContentTypeProtobuf)
 
 	serializers := []serializerType{
 		{
@@ -71,6 +74,15 @@ func newSerializersForScheme(scheme *runtime.Scheme, mf json.MetaFactory) []seri
 			EncodesAsText:      true,
 			Serializer:         yamlSerializer,
 		},
+		{
+			AcceptContentTypes: []string{runtime.ContentTypeProtobuf},
+			ContentType:        runtime.ContentTypeProtobuf,
+			FileExtensions:     []string{"pb"},
+			Serializer:         serializer,
+
+			Framer:           protobuf.LengthDelimitedFramer,
+			StreamSerializer: raw,
+		},
 	}
 
 	for _, fn := range serializerExtensions {

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/protobuf_extension.go

@@ -1,48 +0,0 @@
-/*
-Copyright 2014 The Kubernetes 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 serializer
-
-import (
-	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/runtime/serializer/protobuf"
-)
-
-const (
-	// contentTypeProtobuf is the protobuf type exposed for Kubernetes. It is private to prevent others from
-	// depending on it unintentionally.
-	// TODO: potentially move to pkg/api (since it's part of the Kube public API) and pass it in to the
-	//   CodecFactory on initialization.
-	contentTypeProtobuf = "application/vnd.kubernetes.protobuf"
-)
-
-func protobufSerializer(scheme *runtime.Scheme) (serializerType, bool) {
-	serializer := protobuf.NewSerializer(scheme, scheme, contentTypeProtobuf)
-	raw := protobuf.NewRawSerializer(scheme, scheme, contentTypeProtobuf)
-	return serializerType{
-		AcceptContentTypes: []string{contentTypeProtobuf},
-		ContentType:        contentTypeProtobuf,
-		FileExtensions:     []string{"pb"},
-		Serializer:         serializer,
-
-		Framer:           protobuf.LengthDelimitedFramer,
-		StreamSerializer: raw,
-	}, true
-}
-
-func init() {
-	serializerExtensions = append(serializerExtensions, protobufSerializer)
-}