Added Display mode to SalesforceAuthenticationOptions

src/Owin.Security.Providers.Salesforce/SalesforceAuthenticationHandler.cs

@@ -195,7 +195,7 @@ namespace Owin.Security.Providers.Salesforce
             var authorizationEndpoint = ComposeAuthorizationEndpoint(properties);
 
             authorizationEndpoint =
-                $"{authorizationEndpoint}?response_type={"code"}&client_id={Options.ClientId}&redirect_uri={HttpUtility.UrlEncode(redirectUri)}&display={"page"}&immediate={false}&state={Uri.EscapeDataString(state)}";
+                $"{authorizationEndpoint}?response_type={"code"}&client_id={Options.ClientId}&redirect_uri={HttpUtility.UrlEncode(redirectUri)}&display={Options.DisplayMode}&immediate={false}&state={Uri.EscapeDataString(state)}";
 
             if (Options.Scope != null && Options.Scope.Count > 0)
             {

src/Owin.Security.Providers.Salesforce/SalesforceAuthenticationOptions.cs

@@ -26,6 +26,21 @@ namespace Owin.Security.Providers.Salesforce
             public string Environment { get; set; }
         }
 
+        /// <summary>
+        /// Options for Display Mode
+        ///     Changes the login and authorization pages’ display type. Salesforce supports these values.
+        ///     page—Full-page authorization screen(default)
+        ///     popup—Compact dialog optimized for modern web browser popup windows
+        ///     touch—Mobile-optimized dialog designed for modern smartphones, such as Android and iPhone
+        ///     mobile—Mobile-optimized dialog designed for less capable smartphones, such as BlackBerry OS 5
+        /// </summary>
+        public enum Display{
+            page,
+            popup,
+            touch,
+            mobile
+        }
+        
         /// <summary>
         ///     Gets or sets the a pinned certificate validator to use to validate the endpoints used
         ///     in back channel communications belong to Salesforce.
@@ -110,6 +125,10 @@ namespace Owin.Security.Providers.Salesforce
         ///     <see cref="System.Security.Claims.ClaimsIdentity" />.
         /// </summary>
         public string SignInAsAuthenticationType { get; set; }
+        /// <summary>
+        ///     Gets or sets the display—(Optional) 
+        /// </summary>
+        public Display DisplayMode { get; set; }
 
         /// <summary>
         ///     Gets or sets the type used to secure data handled by the middleware.