Adds SecurityContext.usePrivateKeyBytes

tests/standalone/io/http_proxy_advanced_test.dart

Index: tests/standalone/io/http_proxy_advanced_test.dart
diff --git a/tests/standalone/io/http_proxy_advanced_test.dart b/tests/standalone/io/http_proxy_advanced_test.dart
index aeafaf03c2eef55dab3195c2a06d5f1cf5a41af3..3eb0d08c4d7e178890945e228e1acb2c62ae1802 100644
--- a/tests/standalone/io/http_proxy_advanced_test.dart
+++ b/tests/standalone/io/http_proxy_advanced_test.dart
@@ -10,11 +10,12 @@ import "dart:io";
 import 'dart:convert';
 
 String localFile(path) => Platform.script.resolve(path).toFilePath();
+List<int> readLocalFile(path) => (new File(localFile(path))).readAsBytesSync();
 
 SecurityContext serverContext = new SecurityContext()
   ..useCertificateChain(localFile('certificates/server_chain.pem'))
-  ..usePrivateKey(localFile('certificates/server_key.pem'),
-                  password: 'dartdart');
+  ..usePrivateKeyAsBytes(readLocalFile('certificates/server_key.pem'),
+                       password: 'dartdart');
 
 SecurityContext clientContext = new SecurityContext()
   ..setTrustedCertificates(file: localFile('certificates/trusted_certs.pem'));