Adds support for PKCS12 containers to SecurityContext

tests/standalone/io/secure_socket_test.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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
+import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 import "package:path/path.dart";
 import "dart:async";
 import "dart:io";
 
 String localFile(path) => Platform.script.resolve(path).toFilePath();
 
-SecurityContext serverContext = new SecurityContext()
-  ..useCertificateChainSync(localFile('certificates/server_chain.pem'))
-  ..usePrivateKeySync(localFile('certificates/server_key.pem'),
+SecurityContext serverContext(String certType) => new SecurityContext()
+  ..useCertificateChainSync(localFile('certificates/server_chain.$certType'))
+  ..usePrivateKeySync(localFile('certificates/server_key.$certType'),
                       password: 'dartdart');
 
-SecurityContext clientContext = new SecurityContext()
-  ..setTrustedCertificatesSync(localFile('certificates/trusted_certs.pem'));
+SecurityContext clientContext(String certType) => new SecurityContext()
+  ..setTrustedCertificatesSync(localFile(
+      'certificates/trusted_certs.$certType'));
 
-Future<HttpServer> startServer() {
+Future<HttpServer> startServer(String certType) {
   return HttpServer.bindSecure(
       "localhost",
       0,
-      serverContext,
+      serverContext(certType),
       backlog: 5).then((server) {
     server.listen((HttpRequest request) {
       request.listen(
         (_) { },
         onDone: () {
           request.response.contentLength = 100;
           for (int i = 0; i < 10; i++) {
             request.response.add([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
           }
           request.response.close();
         });
     });
     return server;
   });
 }
 
-void main() {
+Future test(String certType) {
   List<int> body = <int>[];
-  startServer().then((server) {
-    SecureSocket.connect("localhost", server.port, context: clientContext)
+  startServer(certType).then((server) {
+    SecureSocket.connect(
+        "localhost", server.port, context: clientContext(certType))
     .then((socket) {
       socket.write("GET / HTTP/1.0\r\nHost: localhost\r\n\r\n");
       socket.close();
       socket.listen(
         (List<int> data) {
           body.addAll(data);
         },
         onDone: () {
           Expect.isTrue(body.length > 100, "$body\n${body.length}");
           Expect.equals(72, body[0]);
           Expect.equals(9, body[body.length - 1]);
           server.close();
         },
         onError: (e, trace) {
           String msg = "Unexpected error $e";
           if (trace != null) msg += "\nStackTrace: $trace";
           Expect.fail(msg);
         });
     });
   });
 }
+
+main() async {
+  asyncStart();
+  await test('pem');
+  await test('p12');
+  asyncEnd();
+}