obsoleted some un-used/legacy code. IMediaFactory it is no longer used and is contained in an old assembly. If we want to re-support this (which i don't think we do), it needs to be manually re-created and implemented, i don't think its been used for quite some time.

src/Umbraco.Core/Services/ContentService.cs

@@ -1941,6 +1941,7 @@ namespace Umbraco.Core.Services
         /// <summary>
         /// Occurs before Create
         /// </summary>
+        [Obsolete("This event should not be used, it was originally created for backwards compatibility for the legacy API. To modify a new document before it is saved use the Saving event")]
         public static event TypedEventHandler<IContentService, NewEventArgs<IContent>> Creating;
 
         /// <summary>
@@ -1950,6 +1951,7 @@ namespace Umbraco.Core.Services
         /// Please note that the Content object has been created, but might not have been saved
         /// so it does not have an identity yet (meaning no Id has been set).
         /// </remarks>
+        [Obsolete("This event should not be used, it was originally created for backwards compatibility for the legacy API. To modify a new document before it is saved use the Saving event")]
         public static event TypedEventHandler<IContentService, NewEventArgs<IContent>> Created;
 
         /// <summary>

src/Umbraco.Core/Services/MediaService.cs

@@ -998,6 +998,7 @@ namespace Umbraco.Core.Services
 		/// <summary>
 		/// Occurs before Create
 		/// </summary>
+		[Obsolete("This event should not be used, it was originally created for backwards compatibility for the legacy API. To modify a new document before it is saved use the Saving event")]
 		public static event TypedEventHandler<IMediaService, NewEventArgs<IMedia>> Creating;
 
 		/// <summary>
@@ -1007,6 +1008,7 @@ namespace Umbraco.Core.Services
 		/// Please note that the Media object has been created, but not saved
 		/// so it does not have an identity yet (meaning no Id has been set).
 		/// </remarks>
+        [Obsolete("This event should not be used, it was originally created for backwards compatibility for the legacy API. To modify a new document before it is saved use the Saving event")]
 		public static event TypedEventHandler<IMediaService, NewEventArgs<IMedia>> Created;
 
 		/// <summary>

src/Umbraco.Web/umbraco.presentation/umbraco/webservices/MediaUploader.ashx.cs

@@ -19,6 +19,7 @@ using Umbraco.Core;
 
 namespace umbraco.presentation.umbraco.webservices
 {
+    [Obsolete("This should no longer be used, use the WebApi methods to upload media")]
     public class MediaUploader : IHttpHandler
     {
         protected User AuthenticatedUser { get; set; }

src/umbraco.cms/businesslogic/media/IMediaFactory.cs

@@ -6,6 +6,7 @@ using umbraco.BusinessLogic;
 
 namespace umbraco.cms.businesslogic.media
 {
+    [Obsolete("This interface is no longer used and will be removed from the codebase in future versions")]
     public interface IMediaFactory
     {
         List<string> Extensions { get; }

src/umbraco.cms/businesslogic/media/UmbracoFileMediaFactory.cs

@@ -10,6 +10,7 @@ using Umbraco.Core.IO;
 
 namespace umbraco.cms.businesslogic.media
 {
+    [Obsolete("This is no longer used and will be removed from the codebase in future versions")]
     public class UmbracoFileMediaFactory : UmbracoMediaFactory
     {
         public override string MediaTypeAlias

src/umbraco.cms/businesslogic/media/UmbracoImageMediaFactory.cs

@@ -1,10 +1,12 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using Umbraco.Core.Models;
 using umbraco.BusinessLogic;
 using Umbraco.Core;
 
 namespace umbraco.cms.businesslogic.media
 {
+    [Obsolete("This interface is no longer used and will be removed from the codebase in future versions")]
     public class UmbracoImageMediaFactory : UmbracoMediaFactory
     {
         public override string MediaTypeAlias

src/umbraco.cms/businesslogic/media/UmbracoMediaFactory.cs

@@ -12,6 +12,7 @@ using Umbraco.Core;
 
 namespace umbraco.cms.businesslogic.media
 {
+    [Obsolete("This is no longer used and will be removed from the codebase in future versions")]
     public abstract class UmbracoMediaFactory : IMediaFactory
     {
         public abstract List<string> Extensions { get; }

src/umbraco.interfaces/IMacroGuiRendering.cs

@@ -5,6 +5,7 @@ namespace umbraco.interfaces
 	/// <summary>
 	/// Summary description for IMacroGuiRendering.
 	/// </summary>
+	[Obsolete("This interface is no longer used and will be removed from the codebase in future versions")]
 	public interface IMacroGuiRendering
 	{
         /// <summary>