Remove deprecated dart:utf library.

utils/tests/string_encoding/utf8_benchmarks.dart

 #!/usr/bin/env 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 BenchmarkTests;
 import 'dart:io';
 import 'dart:math' as Math;
-import '../../../lib/utf/utf.dart' as SE;
+import '../../../lib/convert/convert.dart' as SE;
 part 'benchmark_runner.dart';
 
 void main() {
 
   final List<int> testEnglishUtf8 = const<int> [
       0x54, 0x68, 0x65, 0x20, 0x71, 0x75, 0x69, 0x63,
       0x6b, 0x20, 0x62, 0x72, 0x6f, 0x77, 0x6e, 0x20,
       0x66, 0x6f, 0x78, 0x20, 0x6a, 0x75, 0x6d, 0x70,
       0x73, 0x20, 0x6f, 0x76, 0x65, 0x72, 0x20, 0x74,
       0x68, 0x65, 0x20, 0x6c, 0x61, 0x7a, 0x79, 0x20,
@@ skipping 75 matching lines @@
       0x82, 0xa2, 0xe3, 0x82, 0xb5, 0xe3, 0x82, 0xad,
       0xe3, 0x83, 0xa6, 0xe3, 0x83, 0xa1, 0xe3, 0x83,
       0x9f, 0xe3, 0x82, 0xb7, 0x20, 0xe3, 0x83, 0xb1,
       0xe3, 0x83, 0x92, 0xe3, 0x83, 0xa2, 0xe3, 0x82,
       0xbb, 0xe3, 0x82, 0xb9, 0xe3, 0x83, 0xb3];
 
   TimedTestConfig testConfig_1sec =
       new TimedTestConfig(100, 1 * 1000, blocksize: 1000);
 
   BenchmarkRunner.runTimed("SE_EN1","string_encoding/decodeUtf8-English1",
-      testConfig_1sec, () =>
-          (new SE.Utf8Decoder(testEnglishUtf8)).decodeRest());
+      testConfig_1sec, () => SE.UTF8.decode(testEnglishUtf8));
 
   BenchmarkRunner.runTimed("SE_DA1","string_encoding/decodeUtf8-Danish1",
-      testConfig_1sec, () => (new SE.Utf8Decoder(testDanishUtf8)).decodeRest());
+      testConfig_1sec, () => SE.UTF8.decode(testDanishUtf8));
 
   BenchmarkRunner.runTimed("SE_HE1","string_encoding/decodeUtf8-Hebrew1",
-      testConfig_1sec, () => (new SE.Utf8Decoder(testHebrewUtf8)).decodeRest());
+      testConfig_1sec, () => SE.UTF8.decode(testHebrewUtf8));
 
   BenchmarkRunner.runTimed("SE_RU1","string_encoding/decodeUtf8-Russian1",
-      testConfig_1sec, () =>
-          (new SE.Utf8Decoder(testRussianUtf8)).decodeRest());
+      testConfig_1sec, () => SE.UTF8.decode(testRussianUtf8));
 
   BenchmarkRunner.runTimed("SE_EL1","string_encoding/decodeUtf8-Greek",
-      testConfig_1sec, () =>
-          (new SE.Utf8Decoder(testGreekUtf8)).decodeRest());
+      testConfig_1sec, () => SE.UTF8.decode(testGreekUtf8));
 
   BenchmarkRunner.runTimed("SE_JA1","string_encoding/decodeUtf8-Katakana",
-      testConfig_1sec, () =>
-          (new SE.Utf8Decoder(testKatakanaUtf8)).decodeRest());
+      testConfig_1sec, () => SE.UTF8.decode(testKatakanaUtf8));
 }
-