Improve the style of code in lib/.

lib/src/crypto_utils.dart

 // Copyright (c) 2012, 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.
 
 library crypto.crypto_utils;
 
 import 'base64.dart';
 
 /// Utility methods for working with message digests.
 abstract class CryptoUtils {
@@ skipping 13 matching lines @@
   ///
   /// The list can be any list of integers from 0 to 255 inclusive, for example
   /// a message digest.
   ///
   /// If [addLineSeparator] is true, the resulting string will  be
   /// broken into lines of 76 characters, separated by "\r\n".
   ///
   /// If [urlSafe] is true, the resulting string will be URL- and filename-
   /// safe.
   static String bytesToBase64(List<int> bytes,
-      {bool urlSafe: false, bool addLineSeparator: false}) {
-    return BASE64.encode(bytes,
-        urlSafe: urlSafe, addLineSeparator: addLineSeparator);
-  }
+          {bool urlSafe: false, bool addLineSeparator: false}) =>
+      BASE64.encode(bytes,
+          urlSafe: urlSafe, addLineSeparator: addLineSeparator);
 
   /// Converts a [Base64-encoded][rfc] String into list of bytes.
   ///
   /// [rfc]: https://tools.ietf.org/html/rfc4648
   ///
   /// This ignores "\r\n" sequences in [input]. It accepts both URL-safe and
   /// -unsafe Base 64 encoded strings.
   ///
   /// Throws a [FormatException] if [input] contains invalid characters.
-  static List<int> base64StringToBytes(String input) {
-    return BASE64.decode(input);
-  }
+  static List<int> base64StringToBytes(String input) => BASE64.decode(input);
 }