Gets sln building and manually merges the entity/media service changes

src/Umbraco.Web/Trees/MediaTreeController.cs

@@ -17,6 +17,7 @@ using Umbraco.Web.WebApi.Filters;
 using Umbraco.Web.Models.ContentEditing;
 using Umbraco.Web.Search;
 using Constants = Umbraco.Core.Constants;
+using Umbraco.Core.Services.Implement;
 
 namespace Umbraco.Web.Trees
 {
@@ -163,7 +164,7 @@ namespace Umbraco.Web.Trees
             return _treeSearcher.ExamineSearch(Umbraco, query, UmbracoEntityTypes.Media, pageSize, pageIndex, out totalFound, searchFrom);
         }
 
-        internal override IEnumerable<IUmbracoEntity> GetChildrenFromEntityService(int entityId)
+        internal override IEnumerable<IEntitySlim> GetChildrenFromEntityService(int entityId)
             // Not pretty having to cast the service, but it is the only way to get to use an internal method that we
             // do not want to make public on the interface. Unfortunately also prevents this from being unit tested.
             // See this issue for details on why we need this: