Share LibrarySpecificUnits when possible

pkg/analyzer/test/src/task/dart_work_manager_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.
 
 library analyzer.test.src.task.dart_work_manager_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart' show ScannerErrorCode;
 import 'package:analyzer/src/generated/engine.dart'
@@ skipping 49 matching lines @@
     expect(manager.unknownSourceQueue, unorderedEquals(sources));
   }
 
   void setUp() {
     cache = context.analysisCache;
     manager = new DartWorkManager(context);
     entry1 = _getOrCreateEntry(source1);
     entry2 = _getOrCreateEntry(source2);
     entry3 = _getOrCreateEntry(source3);
     entry4 = _getOrCreateEntry(source4);
+    when(context.canonicalizeTarget(anyObject)).thenInvoke((target) => target);
   }
 
   void test_applyChange_add() {
     // add source1
     manager.applyChange([source1], [], []);
     expect_unknownSourceQueue([source1]);
     expect_librarySourceQueue([]);
     // add source2
     manager.applyChange([source2], [], []);
     expect_librarySourceQueue([]);
@@ skipping 726 matching lines @@
 class _SourceFactoryMock extends TypedMock implements SourceFactory {}
 
 class _SourceMock extends TypedMock implements Source {
   final String shortName;
   _SourceMock(this.shortName);
   @override
   String get fullName => '/' + shortName;
   @override
   String toString() => fullName;
 }