Drop the crypto dependency.

lib/src/utils.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:async';
 import 'dart:convert';
 import 'dart:math' as math;
 
 import 'package:async/async.dart' hide StreamQueue;
-import 'package:crypto/crypto.dart';
 import 'package:path/path.dart' as p;
 import 'package:shelf/shelf.dart' as shelf;
 import 'package:stack_trace/stack_trace.dart';
 
 import 'backend/operating_system.dart';
 import 'util/path_handler.dart';
 import 'util/stream_queue.dart';
 
 /// The maximum console line length.
 const _lineLength = 100;
@@ skipping 400 matching lines @@
 /// This is useful for making a block of code async without forcing the
 /// containing method to return a future.
 void invoke(fn()) {
   fn();
 }
 
 /// Returns a random base64 string containing [bytes] bytes of data.
 ///
 /// [seed] is passed to [math.Random]; [urlSafe] and [addLineSeparator] are
 /// passed to [CryptoUtils.bytesToBase64].
-String randomBase64(int bytes, {int seed, bool urlSafe: false,
-    bool addLineSeparator: false}) {
+String randomBase64(int bytes, {int seed}) {
   var random = new math.Random(seed);
   var data = [];
   for (var i = 0; i < bytes; i++) {
     data.add(random.nextInt(256));
   }
-  return CryptoUtils.bytesToBase64(data,
-      urlSafe: urlSafe, addLineSeparator: addLineSeparator);
+  return BASE64.encode(data);
 }
 
 /// Returns middleware that nests all requests beneath the URL prefix [beneath].
 shelf.Middleware nestingMiddleware(String beneath) {
   return (handler) {
     var pathHandler = new PathHandler()..add(beneath, handler);
     return pathHandler.handler;
   };
 }