Change MirrorSystem.libraries to Map<Uri, String>

tests/compiler/dart2js/deferred_load_graph_segmentation_test.dart

 // Copyright (c) 2013, 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 the graph segmentation algorithm used by deferred loading
 // to determine which elements can be deferred and which libraries
 // much be included in the initial download (loaded eagerly).
 
 import 'dart:async' show Future;
 import 'dart:uri' show Uri;
 import 'dart:io';
 
 import '../../../sdk/lib/_internal/compiler/implementation/apiimpl.dart'
        show Compiler;
 
 import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart'
        as dart2js;
 
 import '../../../sdk/lib/_internal/compiler/implementation/filenames.dart'
-       show getCurrentDirectory, nativeToUriPath;
+       show currentDirectory, nativeToUriPath;
 
 import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart'
        show SourceFile;
 
 import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.dart'
        show FormattingDiagnosticHandler,
             SourceFileProvider;
 
 class MemorySourceFileProvider extends SourceFileProvider {
   Future<String> readStringFromUri(Uri resourceUri) {
     if (resourceUri.scheme != 'memory') {
       return super.readStringFromUri(resourceUri);
     }
     String source = MEMORY_SOURCE_FILES[resourceUri.path];
     // TODO(ahe): Return new Future.immediateError(...) ?
     if (source == null) throw 'No such file $resourceUri';
     String resourceName = '$resourceUri';
     this.sourceFiles[resourceName] = new SourceFile(resourceName, source);
     return new Future.immediate(source);
   }
 }
 
 void main() {
-  Uri cwd = getCurrentDirectory();
-  Uri script = cwd.resolve(nativeToUriPath(new Options().script));
+  Uri script = currentDirectory.resolve(nativeToUriPath(new Options().script));
   Uri libraryRoot = script.resolve('../../../sdk/');
   Uri packageRoot = script.resolve('./packages/');
 
   var provider = new MemorySourceFileProvider();
   var handler = new FormattingDiagnosticHandler(provider);
 
   Compiler compiler = new Compiler(provider.readStringFromUri,
                                    (name, extension) => null,
                                    handler.diagnosticHandler,
                                    libraryRoot,
@@ skipping 41 matching lines @@
 class MyClass {
   const MyClass();
 
   foo(x) {
     new Expando();
     return (x - 3) ~/ 2;
   }
 }
 """,
 };