pkg/cri: split out NRI API from pkg/cri/server.

Split out the criService-agnostic bits of nri-api* from
pkg/cri/server to pkg/cri/nri to allow sharing a single
implementation betwen the server and sbserver versions.
Rework the interfaces to not require access to package
internals.

Signed-off-by: Krisztian Litkey <krisztian.litkey@intel.com>

pkg/cri/nri/nri_api.go

@@ -0,0 +1,36 @@
+/*
+   Copyright The containerd 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 nri
+
+import (
+	"context"
+	"time"
+
+	criconfig "github.com/containerd/containerd/pkg/cri/config"
+	cstore "github.com/containerd/containerd/pkg/cri/store/container"
+	sstore "github.com/containerd/containerd/pkg/cri/store/sandbox"
+	cri "k8s.io/cri-api/pkg/apis/runtime/v1"
+)
+
+type CRIImplementation interface {
+	Config() *criconfig.Config
+	SandboxStore() *sstore.Store
+	ContainerStore() *cstore.Store
+	ContainerMetadataExtensionKey() string
+	UpdateContainerResources(context.Context, cstore.Container, *cri.UpdateContainerResourcesRequest, cstore.Status) (cstore.Status, error)
+	StopContainer(context.Context, cstore.Container, time.Duration) error
+}