[ADF-4225] Viewer extension accept multiple file type (#4427)

* viewer extension can target multiple types.

* fix lint

lib/extensions/src/lib/components/public-api.ts

@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
+export * from './viewer/viewer-extension.interface';
 export * from './viewer/preview-extension.component';
 export * from './dynamic-column/dynamic-column.component';
 export * from './dynamic-component/dynamic.component';

lib/extensions/src/lib/components/viewer/viewer-extension.interface.ts

@@ -0,0 +1,24 @@
+/*!
+ * @license
+ * Copyright 2019 Alfresco Software, Ltd.
+ *
+ * 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.
+ */
+
+import { Node } from '@alfresco/js-api';
+
+export interface ViewerExtensionInterface {
+    url: string;
+    nameFile: string;
+    node: Node;
+}