Fix incorrect handler delegation and update SignInScheme documentation

src/Microsoft.AspNet.Authentication.OAuth/OAuthAuthenticationOptions.cs

@@ -99,7 +99,10 @@ namespace Microsoft.AspNet.Authentication.OAuth
         public PathString CallbackPath { get; set; }
 
         /// <summary>
-        /// Gets or sets the name of another authentication middleware which will be responsible for actually issuing a user <see cref="System.Security.Claims.ClaimsIdentity"/>.
+        /// Gets or sets the authentication scheme corresponding to the middleware
+        /// responsible of persisting user's identity after a successful authentication.
+        /// This value typically corresponds to a cookie middleware registered in the Startup class.
+        /// When omitted, <see cref="ExternalAuthenticationOptions.SignInScheme"/> is used as a fallback value.
         /// </summary>
         public string SignInScheme { get; set; }
 

src/Microsoft.AspNet.Authentication.OpenIdConnect/OpenIdConnectAuthenticationHandler.cs

@@ -585,4 +585,4 @@ namespace Microsoft.AspNet.Authentication.OpenIdConnect
             return false;
         }
     }
-}
+}

src/Microsoft.AspNet.Authentication.OpenIdConnect/OpenIdConnectAuthenticationMiddleware.cs

@@ -7,12 +7,12 @@ using System.Diagnostics.CodeAnalysis;
 using System.IdentityModel.Tokens;
 using System.Net.Http;
 using System.Text;
-using Microsoft.AspNet.Builder;
-using Microsoft.AspNet.DataProtection;
-using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Authentication.DataHandler;
 using Microsoft.AspNet.Authentication.DataHandler.Encoder;
 using Microsoft.AspNet.Authentication.DataHandler.Serializer;
+using Microsoft.AspNet.Builder;
+using Microsoft.AspNet.DataProtection;
+using Microsoft.AspNet.Http;
 using Microsoft.Framework.Logging;
 using Microsoft.Framework.OptionsModel;
 using Microsoft.IdentityModel.Protocols;
@@ -45,9 +45,14 @@ namespace Microsoft.AspNet.Authentication.OpenIdConnect
         {
             _logger = loggerFactory.CreateLogger<OpenIdConnectAuthenticationMiddleware>();
 
+            if (string.IsNullOrEmpty(Options.SignInScheme))
+            {
+                Options.SignInScheme = externalOptions.Options.SignInScheme;
+            }
+
             if (string.IsNullOrWhiteSpace(Options.TokenValidationParameters.AuthenticationType))
             {
-                Options.TokenValidationParameters.AuthenticationType = externalOptions.Options.SignInScheme;
+                Options.TokenValidationParameters.AuthenticationType = Options.AuthenticationScheme;
             }
 
             if (Options.StateDataFormat == null)

src/Microsoft.AspNet.Authentication.OpenIdConnect/OpenIdConnectAuthenticationOptions.cs

@@ -233,13 +233,12 @@ namespace Microsoft.AspNet.Authentication.OpenIdConnect
         public string Scope { get; set; }
 
         /// <summary>
-        /// Gets or sets the AuthenticationScheme used when creating the <see cref="System.Security.Claims.ClaimsIdentity"/>.
+        /// Gets or sets the authentication scheme corresponding to the middleware
+        /// responsible of persisting user's identity after a successful authentication.
+        /// This value typically corresponds to a cookie middleware registered in the Startup class.
+        /// When omitted, <see cref="ExternalAuthenticationOptions.SignInScheme"/> is used as a fallback value.
         /// </summary>
-        public string SignInScheme
-        {
-            get { return TokenValidationParameters.AuthenticationType; }
-            set { TokenValidationParameters.AuthenticationType = value; }
-        }
+        public string SignInScheme { get; set; }
 
         /// <summary>
         /// Gets or sets the type used to secure data handled by the middleware.

src/Microsoft.AspNet.Authentication.Twitter/TwitterAuthenticationOptions.cs

@@ -89,7 +89,10 @@ namespace Microsoft.AspNet.Authentication.Twitter
         public PathString CallbackPath { get; set; }
 
         /// <summary>
-        /// Gets or sets the name of another authentication middleware which will be responsible for actually issuing a user <see cref="System.Security.Claims.ClaimsIdentity"/>.
+        /// Gets or sets the authentication scheme corresponding to the middleware
+        /// responsible of persisting user's identity after a successful authentication.
+        /// This value typically corresponds to a cookie middleware registered in the Startup class.
+        /// When omitted, <see cref="ExternalAuthenticationOptions.SignInScheme"/> is used as a fallback value.
         /// </summary>
         public string SignInScheme { get; set; }
 

src/Microsoft.AspNet.Authentication/ExternalAuthenticationOptions.cs

@@ -8,6 +8,11 @@ namespace Microsoft.AspNet.Authentication
 {
     public class ExternalAuthenticationOptions
     {
+        /// <summary>
+        /// Gets or sets the authentication scheme corresponding to the default middleware
+        /// responsible of persisting user's identity after a successful authentication.
+        /// This value typically corresponds to a cookie middleware registered in the Startup class.
+        /// </summary>
         public string SignInScheme { get; set; }
     }
 }