Refactored the ManifestContentAppDefinition to have a factory and a seperate data class.

src/Umbraco.Web/ContentApps/ContentEditorContentAppFactory.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using Umbraco.Core.Models;
+using Umbraco.Core.Models.ContentEditing;
+using Umbraco.Core.Models.Membership;
+
+namespace Umbraco.Web.ContentApps
+{
+    internal class ContentEditorContentAppFactory : IContentAppFactory
+    {
+        // see note on ContentApp
+        private const int Weight = -100;
+
+        private ContentApp _contentApp;
+        private ContentApp _mediaApp;
+
+        public ContentApp GetContentAppFor(object o, IEnumerable<IReadOnlyUserGroup> userGroups)
+        {
+            switch (o)
+            {
+                case IContent _:
+                    return _contentApp ?? (_contentApp = new ContentApp
+                    {
+                        Alias = "umbContent",
+                        Name = "Content",
+                        Icon = "icon-document",
+                        View = "views/content/apps/content/content.html",
+                        Weight = Weight
+                    });
+
+                case IMedia media when !media.ContentType.IsContainer && media.ContentType.Alias != Core.Constants.Conventions.MediaTypes.Folder:
+                    return _mediaApp ?? (_mediaApp = new ContentApp
+                    {
+                        Alias = "umbContent",
+                        Name = "Content",
+                        Icon = "icon-document",
+                        View = "views/media/apps/content/content.html",
+                        Weight = Weight
+                    });
+
+                case IMedia _:
+                    return null;
+
+                default:
+                    throw new NotSupportedException($"Object type {o.GetType()} is not supported here.");
+            }
+        }
+    }
+}