Make the manager protected

src/filehandler/handler.ts

@@ -68,13 +68,6 @@ abstract class AbstractFileHandler<T extends Widget> implements IMessageFilter {
     return [];
   }
 
-  /**
-   * Get the contents manager used by the handler.
-   */
-  get manager(): IContentsManager {
-    return this._manager;
-  }
-
   /**
    * Find a widget given a path.
    */
@@ -250,6 +243,13 @@ abstract class AbstractFileHandler<T extends Widget> implements IMessageFilter {
     return false;
   }
 
+  /**
+   * Get the contents manager used by the handler.
+   */
+  protected get manager(): IContentsManager {
+    return this._manager;
+  }
+
   /**
    * Get options use to fetch the model contents from disk.
    */