Use words please.

runtime/observatory/tests/service/graph_test.dart

 // Copyright (c) 2014, 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.
 // VMOptions=--compile-all --error_on_bad_type --error_on_bad_override
 
 import 'dart:async';
 import 'package:observatory/object_graph.dart';
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
@@ skipping 67 matching lines @@
       ObjectVertex first = lists[0];
       ObjectVertex second = lists[1];
       // Check that the short list retains more than the long list inside.
       expect(first.succ.length, equals(2 + second.succ.length));
       // ... and specifically, that it retains exactly itself + the long one.
       expect(first.retainedSize,
           equals(first.shallowSize + second.shallowSize));
       completer.complete();
     }
   });
-  return isolate.rootLib.load().then((Library lib) {
+  return isolate.rootLibrary.load().then((Library lib) {
     expect(lib.classes.length, equals(1));
     Class fooClass = lib.classes.first;
     fooId = fooClass.vmCid;
     isolate.invokeRpcNoUpgrade('requestHeapSnapshot', {});
     return completer.future;
   });
 },
 
 ];
 
 main(args) => runIsolateTests(args, tests, testeeBefore: script);