Add GPL modules

MediaBrowser.Controller/Library/ILibraryPostScanTask.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Controller.Library
+{
+    /// <summary>
+    /// An interface for tasks that run after the media library scan
+    /// </summary>
+    public interface ILibraryPostScanTask
+    {
+        /// <summary>
+        /// Runs the specified progress.
+        /// </summary>
+        /// <param name="progress">The progress.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>Task.</returns>
+        Task Run(IProgress<double> progress, CancellationToken cancellationToken);
+    }
+}