Some more removals of dart:utf.

pkg/csslib/test/compiler_test.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 compiler_test;
 
-import 'dart:utf';
+import 'dart:convert';
 import 'package:unittest/unittest.dart';
 import 'package:csslib/parser.dart';
 import 'package:csslib/visitor.dart';
 import 'testing.dart';
 
 void testClass() {
   var errors = [];
   var input = ".foobar {}";
   var stylesheet = parseCss(input, errors: errors);
 
@@ skipping 496 matching lines @@
 /** Test List<int> as input to parser. */
 void testArrayOfChars() {
   var errors = [];
   var input = '<![CDATA[.foo { '
       'color: red; left: 20px; top: 20px; width: 100px; height:200px'
     '}'
     '#div {'
       'color : #00F578; border-color: #878787;'
     '}]]>';
 
-  var stylesheet = parse(encodeUtf8(input), errors: errors);
+  var stylesheet = parse(UTF8.encode(input), errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   expect(prettyPrint(stylesheet), r'''
 .foo {
   color: #f00;
   left: 20px;
   top: 20px;
   width: 100px;
@@ skipping 184 matching lines @@
   test('Selector Groups', testSelectorGroups);
   test('Combinator', testCombinator);
   test('Wildcards', testWildcard);
   test('Pseudo', testPseudo);
   test('Attributes', testAttribute);
   test('Negation', testNegation);
   test('@host', testHost);
   test('Parse List<int> as input', testArrayOfChars);
   test('Simple Emitter', testEmitter);
 }