Revert "Removed SecurityContext.alpnSupported, as ALPN is now supported on all platforms. Also upda…

pkg/dev_compiler/tool/input_sdk/patch/io_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:_js_helper' show patch;
 
 @patch
 class _Directory {
   @patch
   static _current() {
@@ skipping 441 matching lines @@
 class SecurityContext {
   @patch
   factory SecurityContext() {
     throw new UnsupportedError("SecurityContext constructor");
   }
 
   @patch
   static SecurityContext get defaultContext {
     throw new UnsupportedError("default SecurityContext getter");
   }
+
+  @patch
+  @deprecated
+  static bool get alpnSupported {
+    throw new UnsupportedError("SecurityContext alpnSupported getter");
+  }
 }
 
 @patch
 class X509Certificate {
   @patch
   factory X509Certificate._() {
     throw new UnsupportedError("X509Certificate constructor");
   }
 }
 
@@ skipping 138 matching lines @@
   }
 }
 
 @patch
 class _IOService {
   @patch
   static Future _dispatch(int request, List data) {
     throw new UnsupportedError("_IOService._dispatch");
   }
 }