move additional methods from factory

pkg/kubectl/polymorphichelpers/historyviewer.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2018 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 polymorphichelpers
+
+import (
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/kubernetes/pkg/kubectl"
+	"k8s.io/kubernetes/pkg/kubectl/genericclioptions"
+)
+
+// historyViewer Returns a HistoryViewer for viewing change history
+func historyViewer(restClientGetter genericclioptions.RESTClientGetter, mapping *meta.RESTMapping) (kubectl.HistoryViewer, error) {
+	clientConfig, err := restClientGetter.ToRESTConfig()
+	if err != nil {
+		return nil, err
+	}
+
+	external, err := kubernetes.NewForConfig(clientConfig)
+	if err != nil {
+		return nil, err
+	}
+	return kubectl.HistoryViewerFor(mapping.GroupVersionKind.GroupKind(), external)
+}