Mono-specific HttpListener additions. (#19490)

* Mono-specific HttpListener additions.

* Wrap HttpListener.CreateSslStream() in '!MONO' conditional.

* Add call to HttpListener.LoadCertificateAndKey() to HttpEndPointListener's .ctor.

* Use a new partial class instead of conditionals.

* Make it build.

Author: Martin Baulig

src/System.Net.HttpListener/src/System.Net.HttpListener.csproj

@@ -329,6 +329,7 @@
     <Compile Include="System\Net\Managed\ListenerPrefix.cs" />
     <Compile Include="System\Net\Managed\HttpRequestStream.Managed.cs" />
     <Compile Include="System\Net\Managed\HttpListener.Managed.cs" />
+    <Compile Include="System\Net\Managed\HttpListener.Certificates.cs" />
     <Compile Include="System\Net\Managed\HttpListenerContext.Managed.cs" />
     <Compile Include="System\Net\Managed\HttpListenerRequest.Managed.cs" />
     <Compile Include="System\Net\Managed\HttpListenerResponse.Managed.cs" />

src/System.Net.HttpListener/src/System/Net/Managed/HttpConnection.cs

@@ -116,6 +116,11 @@ internal X509Certificate2 ClientCertificate
             get { return _clientCert; }
         }
 
+        internal SslStream SslStream
+        {
+            get { return _sslStream; }
+        }
+
         private void Init()
         {
             if (_sslStream != null)

src/System.Net.HttpListener/src/System/Net/Managed/HttpEndPointListener.cs

@@ -55,8 +55,7 @@ public HttpEndPointListener(HttpListener listener, IPAddress addr, int port, boo
             if (secure)
             {
                 _secure = secure;
-                // TODO #14691: Implement functionality to read SSL certificate.
-                _cert = null;
+                _cert = _listener.LoadCertificateAndKey (addr, port);
             }
 
             _endpoint = new IPEndPoint(addr, port);

src/System.Net.HttpListener/src/System/Net/Managed/HttpListener.Certificates.cs

@@ -0,0 +1,26 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Net.Security;
+using System.Security.Cryptography.X509Certificates;
+
+namespace System.Net
+{
+    partial class HttpListener
+    {
+        internal SslStream CreateSslStream(Stream innerStream, bool ownsStream, RemoteCertificateValidationCallback callback)
+        {
+            return new SslStream(innerStream, ownsStream, callback);
+        }
+
+        internal X509Certificate LoadCertificateAndKey(IPAddress addr, int port)
+        {
+            // TODO #14691: Implement functionality to read SSL certificate.
+            return null;
+        }
+    }
+}

src/System.Net.HttpListener/src/System/Net/Managed/HttpListener.Managed.cs

@@ -18,11 +18,6 @@ public sealed unsafe partial class HttpListener
         private List<ListenerAsyncResult> _asyncWaitQueue = new List<ListenerAsyncResult>();
         private Dictionary<HttpConnection, HttpConnection> _connections = new Dictionary<HttpConnection, HttpConnection>();
 
-        internal SslStream CreateSslStream(Stream innerStream, bool ownsStream, RemoteCertificateValidationCallback callback)
-        {
-            return new SslStream(innerStream, ownsStream, callback);
-        }
-
         public HttpListenerTimeoutManager TimeoutManager
         {
             get