Some more removals of dart:utf.

pkg/scheduled_test/lib/src/descriptor/file_descriptor.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.
 
 library descriptor.file;
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
 import 'dart:math' as math;
-import 'dart:utf';
 
 import 'package:path/path.dart' as path;
 
 import '../../descriptor.dart';
 import '../../scheduled_test.dart';
 import '../utils.dart';
 
 /// A descriptor describing a single file.
 abstract class FileDescriptor extends Descriptor implements ReadableDescriptor {
   /// The contents of the file, in bytes.
@@ skipping 62 matching lines @@
 
   Future _validateNow(List<int> actualContents) {
     if (orderedIterableEquals(contents, actualContents)) return null;
     // TODO(nweiz): show a hex dump here if the data is small enough.
     throw "File '$name' didn't contain the expected binary data.";
   }
 }
 
 class _StringFileDescriptor extends FileDescriptor {
   _StringFileDescriptor(String name, String contents)
-      : super._(name, encodeUtf8(contents));
+      : super._(name, UTF8.encode(contents));
 
   Future _validateNow(List<int> actualContents) {
     if (orderedIterableEquals(contents, actualContents)) return null;
     throw _textMismatchMessage(textContents,
         new String.fromCharCodes(actualContents));
   }
 
   String _textMismatchMessage(String expected, String actual) {
     final expectedLines = expected.split('\n');
     final actualLines = actual.split('\n');
@@ skipping 36 matching lines @@
 
   _MatcherFileDescriptor(String name, this._matcher, {bool isBinary})
       : _isBinary = isBinary == true ? true : false,
         super._(name, <int>[]);
 
   void _validateNow(List<int> actualContents) =>
       expect(
           _isBinary ? actualContents : new String.fromCharCodes(actualContents),
           _matcher);
 }