Keep SocketsHttpHandler out of UAP builds

SocketsHttpHandler is not supported in uap and is currently leaking into UAP builds since they've been disabled for a few weeks. Adjust the contract so it's not available to UAP, and clean the implementation assembly so SocketsHttpHandler internals don't leak out into HttpClientHandler.Core.cs.

src/System.Net.Http/ref/System.Net.Http.SocketsHttpHandler.cs

@@ -0,0 +1,35 @@
+// 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.
+// ------------------------------------------------------------------------------
+// Changes to this file must follow the http://aka.ms/api-review process.
+// ------------------------------------------------------------------------------
+
+
+namespace System.Net.Http
+{
+    public sealed class SocketsHttpHandler : HttpMessageHandler
+    {
+        public SocketsHttpHandler() { }
+        public bool AllowAutoRedirect { get { throw null; } set { } }
+        public System.Net.DecompressionMethods AutomaticDecompression { get { throw null; } set { } }
+        public System.TimeSpan ConnectTimeout { get; set; }
+        public System.Net.CookieContainer CookieContainer { get { throw null; } set { } }
+        public System.Net.ICredentials Credentials { get { throw null; } set { } }
+        public System.Net.ICredentials DefaultProxyCredentials { get { throw null; } set { } }
+        public System.TimeSpan Expect100ContinueTimeout { get; set; }
+        public int MaxAutomaticRedirections { get { throw null; } set { } }
+        public int MaxConnectionsPerServer { get { throw null; } set { } }
+        public int MaxResponseHeadersLength { get { throw null; } set { } }
+        public bool PreAuthenticate { get { throw null; } set { } }
+        public System.TimeSpan PooledConnectionIdleTimeout { get { throw null; } set { } }
+        public System.TimeSpan PooledConnectionLifetime { get { throw null; } set { } }
+        public System.Collections.Generic.IDictionary<string, object> Properties { get { throw null; } }
+        public System.Net.IWebProxy Proxy { get { throw null; } set { } }
+        public System.Net.Security.SslClientAuthenticationOptions SslOptions { get { throw null; } set { } }
+        public bool UseCookies { get { throw null; } set { } }
+        public bool UseProxy { get { throw null; } set { } }
+        protected override void Dispose(bool disposing) { }
+        protected internal override System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { throw null; }
+    }
+}

src/System.Net.Http/ref/System.Net.Http.cs

@@ -236,30 +236,6 @@ public ReadOnlyMemoryContent(System.ReadOnlyMemory<byte> content) { }
         protected override System.Threading.Tasks.Task SerializeToStreamAsync(System.IO.Stream stream, System.Net.TransportContext context) => throw null;
         protected internal override bool TryComputeLength(out long length) => throw null;
     }
-    public sealed class SocketsHttpHandler : HttpMessageHandler
-    {
-        public SocketsHttpHandler() { }
-        public bool AllowAutoRedirect { get { throw null; } set { } }
-        public System.Net.DecompressionMethods AutomaticDecompression { get { throw null; } set { } }
-        public System.TimeSpan ConnectTimeout { get; set; }
-        public System.Net.CookieContainer CookieContainer { get { throw null; } set { } }
-        public System.Net.ICredentials Credentials { get { throw null; } set { } }
-        public System.Net.ICredentials DefaultProxyCredentials { get { throw null; } set { } }
-        public System.TimeSpan Expect100ContinueTimeout { get; set; }
-        public int MaxAutomaticRedirections { get { throw null; } set { } }
-        public int MaxConnectionsPerServer { get { throw null; } set { } }
-        public int MaxResponseHeadersLength { get { throw null; } set { } }
-        public bool PreAuthenticate { get { throw null; } set { } }
-        public System.TimeSpan PooledConnectionIdleTimeout { get { throw null; } set { } }
-        public System.TimeSpan PooledConnectionLifetime { get { throw null; } set { } }
-        public System.Collections.Generic.IDictionary<string, object> Properties { get { throw null; } }
-        public System.Net.IWebProxy Proxy { get { throw null; } set { } }
-        public System.Net.Security.SslClientAuthenticationOptions SslOptions { get { throw null; } set { } }
-        public bool UseCookies { get { throw null; } set { } }
-        public bool UseProxy { get { throw null; } set { } }
-        protected override void Dispose(bool disposing) { }
-        protected internal override System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { throw null; }
-    }
     public partial class StreamContent : System.Net.Http.HttpContent
     {
         public StreamContent(System.IO.Stream content) { }

src/System.Net.Http/ref/System.Net.Http.csproj

@@ -10,6 +10,7 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'uap-Release|AnyCPU'" />
   <ItemGroup>
     <Compile Include="System.Net.Http.cs" />
+    <Compile Include="System.Net.Http.SocketsHttpHandler.cs" Condition="'$(TargetGroup)' != 'uap'" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp' or '$(TargetGroup)' == 'uap'">
     <ProjectReference Include="..\..\System.Runtime\ref\System.Runtime.csproj" />

src/System.Net.Http/src/System/Net/Http/HttpClientHandler.Core.cs

@@ -62,12 +62,5 @@ private void CheckDisposedOrStarted()
                 throw new InvalidOperationException(SR.net_http_operation_started);
             }
         }
-
-        private void ThrowForModifiedManagedSslOptionsIfStarted()
-        {
-            // Hack to trigger an InvalidOperationException if a property that's stored on
-            // SslOptions is changed, since SslOptions itself does not do any such checks.
-            _socketsHttpHandler.SslOptions = _socketsHttpHandler.SslOptions;
-        }
     }
 }

src/System.Net.Http/src/System/Net/Http/HttpClientHandler.Unix.cs

@@ -375,6 +375,13 @@ public int MaxResponseHeadersLength
             }
         }
 
+        private void ThrowForModifiedManagedSslOptionsIfStarted()
+        {
+            // Hack to trigger an InvalidOperationException if a property that's stored on
+            // SslOptions is changed, since SslOptions itself does not do any such checks.
+            _socketsHttpHandler.SslOptions = _socketsHttpHandler.SslOptions;
+        }
+
         public IDictionary<string, object> Properties => _curlHandler != null ?
             _curlHandler.Properties :
             _socketsHttpHandler.Properties;

src/System.Net.Http/src/System/Net/Http/HttpClientHandler.Windows.cs

@@ -463,5 +463,13 @@ protected internal override Task<HttpResponseMessage> SendAsync(HttpRequestMessa
                     _socketsHttpHandler.SendAsync(request, cancellationToken);
             }
         }
+
+        private void ThrowForModifiedManagedSslOptionsIfStarted()
+        {
+            // Hack to trigger an InvalidOperationException if a property that's stored on
+            // SslOptions is changed, since SslOptions itself does not do any such checks.
+            _socketsHttpHandler.SslOptions = _socketsHttpHandler.SslOptions;
+        }
+
     }
 }