Added a completely separate DTOBaseItem to remove the ApiBaseItemWrapper mess and shrink json output size.

MediaBrowser.Model/Entities/IHasProviderIds.cs

@@ -0,0 +1,57 @@
+using System.Collections.Generic;
+
+namespace MediaBrowser.Model.Entities
+{
+    /// <summary>
+    /// Since BaseItem and DTOBaseItem both have ProviderIds, this interface helps avoid code repition using extension methods
+    /// </summary>
+    public interface IHasProviderIds
+    {
+        Dictionary<string, string> ProviderIds { get; set; }
+    }
+
+    public static class IProviderIdsExtensions
+    {
+        /// <summary>
+        /// Gets a provider id
+        /// </summary>
+        public static string GetProviderId(this IHasProviderIds instance, MetadataProviders provider)
+        {
+            return instance.GetProviderId(provider.ToString());
+        }
+
+        /// <summary>
+        /// Gets a provider id
+        /// </summary>
+        public static string GetProviderId(this IHasProviderIds instance, string name)
+        {
+            if (instance.ProviderIds == null)
+            {
+                return null;
+            }
+
+            return instance.ProviderIds[name];
+        }
+
+        /// <summary>
+        /// Sets a provider id
+        /// </summary>
+        public static void SetProviderId(this IHasProviderIds instance, string name, string value)
+        {
+            if (instance.ProviderIds == null)
+            {
+                instance.ProviderIds = new Dictionary<string, string>();
+            }
+
+            instance.ProviderIds[name] = value;
+        }
+
+        /// <summary>
+        /// Sets a provider id
+        /// </summary>
+        public static void SetProviderId(this IHasProviderIds instance, MetadataProviders provider, string value)
+        {
+            instance.SetProviderId(provider.ToString(), value);
+        }
+    }
+}