Refactor LibraryUpdater to prepare for parts.

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;
 
 import 'package:dart2js_incremental/library_updater.dart' show
+    IncrementalCompilerContext,
     LibraryUpdater,
     Update;
 
 import 'compiler_test_case.dart';
 
 void nolog(_) {}
 
 class LibraryUpdaterTestCase extends CompilerTestCase {
   final String newSource;
 
   final bool expectedCanReuse;
 
   final List<String> expectedUpdates;
 
   LibraryUpdaterTestCase(
       {String before,
        String after,
        bool canReuse,
        List<String> updates})
       : this.newSource = after,
         this.expectedCanReuse = canReuse,
         this.expectedUpdates = updates,
         super(before);
 
   Future run() => loadMainApp().then((LibraryElement library) {
+    var context = new IncrementalCompilerContext();
     LibraryUpdater updater =
-        new LibraryUpdater(this.compiler, null, scriptUri, nolog, nolog);
+        new LibraryUpdater(this.compiler, null, nolog, nolog, context);
+    context.registerUriWithUpdates([scriptUri]);
     bool actualCanReuse =
         updater.canReuseLibrary(library, UTF8.encode(newSource));
     Expect.equals(expectedCanReuse, actualCanReuse);
 
     Expect.setEquals(
         expectedUpdates.toSet(),
         updater.updates.map(nameOfUpdate).toSet());
   });
 
   String toString() => 'Before:\n$source\n\n\nAfter:\n$newSource';
@@ skipping 69 matching lines @@
           new LibraryUpdaterTestCase(
               before: 'main() => null;',
               after: 'main() {}',
               canReuse: true,
               updates: ['main']),
 
           // TODO(ahe): When supporting class members, test abstract methods.
       ]
   );
 }