Remove deprecated string features.

tests/corelib/string_base_vm_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.
 // Dart test program for testing class 'StringBase' (currently VM specific).
 
 library string_base_test;
 
 class StringBaseTest {
 
   StringBaseTest() {}
@@ skipping 12 matching lines @@
     s = "${numBottles*3} bottles of beer on the $wall.";
     Expect.equals("99 bottles of beer on the wall.", s);
   }
 
   static testCreation() {
     String s = "Hello";
     List<int> a = new List.fixedLength(s.length);
     List<int> ga  = new List();
     bool exception_caught = false;
     for (int i = 0; i < a.length; i++) {
-      a[i] = s.charCodeAt(i);
-      ga.add(s.charCodeAt(i));
+      a[i] = s.codeUnitAt(i);
+      ga.add(s.codeUnitAt(i));
     }
     try {
       String s4 = new String.fromCharCodes([0.0]);
     } on ArgumentError catch (ex) {
       exception_caught = true;
     }
     Expect.equals(true, exception_caught);
     exception_caught = false;
     try {
       String s4 = new String.fromCharCodes([-1]);
@@ skipping 26 matching lines @@
   static void testMain() {
     testInterpolation();
     testCreation();
     testSubstring();
   }
 }
 
 main() {
   StringBaseTest.testMain();
 }