Use relative URIs for core library part-of statements.

tests/standalone/io/web_socket_error_test.dart

Index: tests/standalone/io/web_socket_error_test.dart
diff --git a/tests/standalone/io/web_socket_error_test.dart b/tests/standalone/io/web_socket_error_test.dart
index 76d0b93acbdf6ad52e9356bc41998712bb1c08f7..0960f7c327173b58a046d5b40430566f5f27951b 100644
--- a/tests/standalone/io/web_socket_error_test.dart
+++ b/tests/standalone/io/web_socket_error_test.dart
@@ -12,6 +12,7 @@
 library dart.io;
 
 import "dart:async";
+import "dart:convert" show BASE64;
 import "dart:io";
 import "dart:math";
 import "dart:typed_data";
@@ -20,7 +21,7 @@ import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 import "package:path/path.dart";
 
-part "../../../sdk/lib/io/crypto.dart";
+import "hash_utils.dart";
 
 const String webSocketGUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 const String CERT_NAME = 'localhost_cert';
@@ -60,9 +61,9 @@ class SecurityConfiguration {
         response.headers.set(HttpHeaders.CONNECTION, "upgrade");
         response.headers.set(HttpHeaders.UPGRADE, "websocket");
         String key = request.headers.value("Sec-WebSocket-Key");
-        _SHA1 sha1 = new _SHA1();
+        var sha1 = new SHA1();
         sha1.add("$key$webSocketGUID".codeUnits);
-        String accept = _CryptoUtils.bytesToBase64(sha1.close());
+        String accept = BASE64.encode(sha1.close());
         response.headers.add("Sec-WebSocket-Accept", accept);
         response.headers.contentLength = 0;
         response.detachSocket().then((socket) {