Remove deprecated string features.

utils/tests/string_encoding/utf16_test.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 utf16_tests;
 import 'dunit.dart';
 import '../../string_encoding/unicode_core.dart';
 import '../../string_encoding/utf16.dart';
 
@@ skipping 100 matching lines @@
         decodeUtf16(testKoreanCharSubsetUtf16beBom), "UTF-16BE Korean");
   }
 
   void testIterableMethods() {
     // empty input
     Expect.isFalse(decodeUtf16AsIterable([]).iterator.moveNext());
 
     IterableUtf16Decoder koreanDecoder =
       decodeUtf16AsIterable(testKoreanCharSubsetUtf16beBom);
     // get the first character
-    Expect.equals(testKoreanCharSubset.charCodes[0], koreanDecoder.first);
+    Expect.equals(testKoreanCharSubset.codeUnits[0], koreanDecoder.first);
     // get the whole translation using the Iterable interface
     Expect.stringEquals(testKoreanCharSubset,
         new String.fromCharCodes(new List<int>.from(koreanDecoder)));
 
     // specify types
     Expect.equals(44032, (new List<int>
         .from(decodeUtf16beAsIterable(testKoreanCharSubsetUtf16beBom)))[0]);
     Expect.equals(44032, (new List<int>
         .from(decodeUtf16leAsIterable(testKoreanCharSubsetUtf16le)))[0]);
     Expect.equals(UNICODE_BOM, (new List<int>
         .from(decodeUtf16beAsIterable(testKoreanCharSubsetUtf16beBom,
               stripBom: false)))[0]);
   }
 }