Remove deprecated string features.

sdk/lib/io/websocket_impl.dart

Index: sdk/lib/io/websocket_impl.dart
diff --git a/sdk/lib/io/websocket_impl.dart b/sdk/lib/io/websocket_impl.dart
index 673fe23331706c318e3cb655e1b863a17e9cd2ad..66c23bab91ddb2361ac337a6727bb0bceec9be74 100644
--- a/sdk/lib/io/websocket_impl.dart
+++ b/sdk/lib/io/websocket_impl.dart
@@ -594,7 +594,7 @@ class _WebSocketHandler implements WebSocketHandler {
     response.headers.add(HttpHeaders.UPGRADE, "websocket");
     String key = request.headers.value("Sec-WebSocket-Key");
     SHA1 sha1 = new SHA1();
-    sha1.add("$key$_webSocketGUID".charCodes);
+    sha1.add("$key$_webSocketGUID".codeUnits);
     String accept = _Base64._encode(sha1.close());
     response.headers.add("Sec-WebSocket-Accept", accept);
     response.contentLength = 0;
@@ -742,7 +742,7 @@ class _WebSocketClientConnection
       return false;
     }
     SHA1 sha1 = new SHA1();
-    sha1.add("$_nonce$_webSocketGUID".charCodes);
+    sha1.add("$_nonce$_webSocketGUID".codeUnits);
     List<int> expectedAccept = sha1.close();
     List<int> receivedAccept = _Base64._decode(accept);
     if (expectedAccept.length != receivedAccept.length) return false;