Add some support for the code-point code-unit distinction.

tests/utils/utf_test.dart

Index: tests/utils/utf_test.dart
diff --git a/tests/utils/utf_test.dart b/tests/utils/utf_test.dart
index 64417895cefb712ea9c078aa65524297b39380ff..fe117dbb21b21918ffe2276170081d54cefd383f 100644
--- a/tests/utils/utf_test.dart
+++ b/tests/utils/utf_test.dart
@@ -6,9 +6,9 @@ library utf_test;
 import 'dart:utf';
 
 main() {
-  String str = codepointsToString([0x1d537]);
-  // String.charCodes gives 16-bit code units, but stringToCodepoints gives
-  // back the original code points.
-  Expect.listEquals([0xd835, 0xdd37], str.charCodes);
-  Expect.listEquals([0x1d537], stringToCodepoints(str));
+  String str = new String.fromCharCodes([0x1d537]);
+  // String.charCodes gives the original code points and String.codeUnits
+  // gives back 16-bit code units
+  Expect.listEquals([0xd835, 0xdd37], str.codeUnits);
+  Expect.listEquals([0x1d537], str.charCodes);
 }