Use words please.

runtime/observatory/tests/service/code_test.dart

 // Copyright (c) 2015, 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 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 import 'dart:async';
 
@@ skipping 13 matching lines @@
 void testFunction() {
   while (true) {
     funcA();
   }
 }
 
 var tests = [
 
 // Go to breakpoint at line 13.
 (Isolate isolate) {
-  return isolate.rootLib.load().then((_) {
+  return isolate.rootLibrary.load().then((_) {
       // Set up a listener to wait for breakpoint events.
       Completer completer = new Completer();
       isolate.vm.events.stream.listen((ServiceEvent event) {
         if (event.eventType == ServiceEvent.kPauseBreakpoint) {
           print('Breakpoint reached');
           completer.complete();
         }
       });
 
       // Add the breakpoint.
-      var script = isolate.rootLib.scripts[0];
+      var script = isolate.rootLibrary.scripts[0];
       var line = 13;
       return isolate.addBreakpoint(script, line).then((ServiceObject bpt) {
           return completer.future;  // Wait for breakpoint reached.
       });
     });
 },
 
 // Inspect code objects for top two frames.
 (Isolate isolate) {
   return isolate.getStack().then((ServiceMap stack) {
@@ skipping 21 matching lines @@
             expect(code.function.name, equals('funcA'));
             expect(code.hasDisassembly, equals(true));
           }));
       return Future.wait(tests);
   });
 },
 
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testFunction);