Use MockSdk to speed-up tests.

pkg/analyzer2dart/lib/src/driver.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 analyzer2dart.driver;
 
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_io.dart';
-import 'package:analyzer/src/generated/sdk_io.dart';
+import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 
 import 'closed_world.dart';
 import 'tree_shaker.dart';
 
 /**
  * Top level driver for Analyzer2Dart.
  */
 class Driver {
   AnalysisContext context;
 
-  Driver() : context = AnalysisEngine.instance.createAnalysisContext() {
+  Driver(DartSdk sdk) : context = AnalysisEngine.instance.createAnalysisContext() {
     // Set up the source factory.
     // TODO(paulberry): do we want to use ExplicitPackageUriResolver?
     List<UriResolver> uriResolvers = [
         new FileUriResolver(),
-        new DartUriResolver(DirectoryBasedDartSdk.defaultSdk) /* ,
+        new DartUriResolver(sdk) /* ,
         new PackageUriResolver(packagesDirectories) */
     ];
     context.sourceFactory = new SourceFactory(uriResolvers);
   }
 
   /**
    * Compute the closed world that is reachable from an entry point.
    */
   ClosedWorld computeWorld(FunctionElement entryPointElement) {
     TreeShaker treeShaker = new TreeShaker();
@@ skipping 39 matching lines @@
     ChangeSet changeSet = new ChangeSet();
     JavaFile javaFile = new JavaFile(path);
     Source source = new FileBasedSource.con1(javaFile);
     changeSet.addedSource(source);
     changeSet.changedContent(source, contents);
     context.applyChanges(changeSet);
     return source;
   }
 }