Add LibraryUpdater.hasPendingUpdates.

dart/tests/try/poi/library_updater_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.
 
 // Test of LibraryUpdater.
 library trydart.library_updater_test;
 
 import 'dart:convert' show
     UTF8;
 
@@ skipping 22 matching lines @@
         this.expectedUpdates = updates,
         super(before);
 
   Future run() => mainApp.then((LibraryElement library) {
     LibraryUpdater updater =
         new LibraryUpdater(this.compiler, null, scriptUri, nolog, nolog);
     bool actualCanReuse =
         updater.canReuseLibrary(library, UTF8.encode(newSource));
     Expect.equals(expectedCanReuse, actualCanReuse);
 
+    Expect.equals(expectedCanReuse, updater.hasPendingUpdates);
+
     Expect.setEquals(
         expectedUpdates.toSet(),
         updater.updates.map((Update update) => update.before.name).toSet());
   });
 
   String toString() => 'Before:\n$source\n\n\nAfter:\n$newSource';
 }
 
 void main() {
   runTests(
@@ skipping 59 matching lines @@
           new LibraryUpdaterTestCase(
               before: 'main() => null;',
               after: 'main() {}',
               canReuse: true,
               updates: ['main']),
 
           // TODO(ahe): When supporting class members, test abstract methods.
       ]
   );
 }