Correcting issue with RepositoryResolver not setting the unit of work when resolving.

src/Umbraco.Core/Models/ContentBase.cs

@@ -27,6 +27,10 @@ namespace Umbraco.Core.Models
 
         protected ContentBase(int parentId, IContentTypeComposition contentType, PropertyCollection properties)
         {
+            Mandate.ParameterCondition(parentId != 0, "parentId");
+            Mandate.ParameterNotNull(contentType, "contentType");
+            Mandate.ParameterNotNull(properties, "properties");
+
             _parentId = parentId;
             _contentTypeId = int.Parse(contentType.Id.ToString(CultureInfo.InvariantCulture));
             ContentTypeBase = contentType;