Extend compiler API to support multiple outputs.

dart/tests/compiler/dart2js/analyze_api_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.
 
 library analyze_api;
 
 import 'dart:uri';
 import 'dart:io';
 import '../../../sdk/lib/_internal/compiler/compiler.dart' as api;
 import '../../../sdk/lib/_internal/compiler/implementation/apiimpl.dart';
@@ skipping 27 matching lines @@
   var uriList = new List<Uri>();
   LIBRARIES.forEach((String name, LibraryInfo info) {
     if (info.documented) {
       uriList.add(new Uri.fromComponents(scheme: 'dart', path: name));
     }
   });
   var provider = new SourceFileProvider();
   var handler = new CollectingDiagnosticHandler(provider);
   var compiler = new Compiler(
       provider.readStringFromUri,
+      null,
       handler.diagnosticHandler,
       libraryRoot, libraryRoot,
       <String>['--analyze-only', '--analyze-all',
                '--categories=Client,Server']);
   compiler.librariesToAnalyzeWhenRun = uriList;
   compiler.run(null);
   Expect.isFalse(handler.hasWarnings);
   Expect.isFalse(handler.hasErrors);
 }