Engine test fix to keep up with SourceFactory changes.

pkg/analyzer/test/generated/engine_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.
 
 library analyzer.test.generated.engine_test;
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/source/embedder.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
+import 'package:analyzer/src/context/source.dart';
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/string_source.dart';
 import 'package:analyzer/task/model.dart';
 import 'package:html/dom.dart' show Document;
 import 'package:typed_mock/typed_mock.dart';
@@ skipping 44 matching lines @@
     if (event.isAnalyzed) {
       analyzedSources.add(event.source);
     } else {
       analyzedSources.remove(event.source);
     }
   }
 }
 
 class CompilationUnitMock extends TypedMock implements CompilationUnit {}
 
-class MockSourceFactory extends SourceFactory {
+class MockSourceFactory extends SourceFactoryImpl {
   MockSourceFactory() : super([]);
   Source resolveUri(Source containingSource, String containedUri) {
     throw new JavaIOException();
   }
 }
 
 @reflectiveTest
 class SourcesChangedEventTest {
   void test_added() {
     var source = new StringSource('', '/test.dart');
@@ skipping 588 matching lines @@
   bool validateCacheConsistency() {
     fail("Unexpected invocation of validateCacheConsistency");
     return false;
   }
 
   @override
   void visitContentCache(ContentCacheVisitor visitor) {
     fail("Unexpected invocation of visitContentCache");
   }
 }