Add variance keywords

Author: Chris Martinez

src/Common/Versioning/Conventions/IActionConventionBuilder{T}.cs

@@ -17,7 +17,7 @@ namespace Microsoft.AspNetCore.Mvc.Versioning.Conventions
 #if !WEBAPI
     [CLSCompliant( false )]
 #endif
-    public interface IActionConventionBuilder<T> : IMapToApiVersionConventionBuilder
+    public interface IActionConventionBuilder<out T> : IMapToApiVersionConventionBuilder
 #if WEBAPI
         where T : IHttpController
 #endif

src/Common/Versioning/Conventions/IApiVersionConvention{T}.cs

@@ -10,7 +10,7 @@ namespace Microsoft.AspNetCore.Mvc.Versioning.Conventions
     /// Defines the behavior of an API version convention.
     /// </summary>
     /// <typeparam name="T">The <see cref="Type">type</see> of item to apply the convention to.</typeparam>
-    public interface IApiVersionConvention<T>
+    public interface IApiVersionConvention<in T>
     {
         /// <summary>
         /// Applies the API version convention.

src/Common/Versioning/Conventions/IControllerConventionBuilder{T}.cs

@@ -13,7 +13,7 @@ namespace Microsoft.AspNetCore.Mvc.Versioning.Conventions
     /// Defines the behavior of a convention builder for a controller.
     /// </summary>
     /// <typeparam name="T">The type of item the convention builder is for.</typeparam>
-    public partial interface IControllerConventionBuilder<T> : IDeclareApiVersionConventionBuilder
+    public partial interface IControllerConventionBuilder<out T> : IDeclareApiVersionConventionBuilder
 #if WEBAPI
         where T : IHttpController
 #endif

src/Microsoft.AspNet.WebApi.Versioning/Versioning/Conventions/IControllerConventionBuilder{T}.cs

@@ -6,7 +6,7 @@
     /// <content>
     /// Provides additional implementation specific to ASP.NET Web API.
     /// </content>
-    public partial interface IControllerConventionBuilder<T> : IApiVersionConvention<HttpControllerDescriptor>
+    public partial interface IControllerConventionBuilder<out T> : IApiVersionConvention<HttpControllerDescriptor>
     {
     }
 }

src/Microsoft.AspNetCore.Mvc.Versioning/Versioning/Conventions/IControllerConventionBuilder{T}.cs

@@ -7,7 +7,7 @@
     /// Provides additional implementation specific to ASP.NET Core.
     /// </content>
     [CLSCompliant( false )]
-    public partial interface IControllerConventionBuilder<T> : IApiVersionConvention<ControllerModel>
+    public partial interface IControllerConventionBuilder<out T> : IApiVersionConvention<ControllerModel>
     {
     }
 }