Add interfaces for a new compiler API.

tests/compiler/dart2js/mirrors_test.dart

 // Copyright (c) 2012, 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.
 
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 import 'package:compiler/src/mirrors/source_mirrors.dart';
 import 'package:compiler/src/mirrors/mirrors_util.dart';
 import 'package:compiler/src/mirrors/analyze.dart';
 import 'package:compiler/src/filenames.dart'
@@ skipping 29 matching lines @@
   }
   return null;
 }
 
 main() {
   Uri scriptUri = currentDirectory.resolveUri(Platform.script);
   Uri packageRoot = scriptUri.resolve('./packages/');
   Uri libUri = scriptUri.resolve('../../../sdk/');
   Uri inputUri = scriptUri.resolve('mirrors_helper.dart');
   var provider = new CompilerSourceFileProvider();
-  var diagnosticHandler =
-        new FormattingDiagnosticHandler(provider).diagnosticHandler;
+  var diagnosticHandler = new FormattingDiagnosticHandler(provider);
   asyncStart();
   var result = analyze([inputUri], libUri, packageRoot,
                        provider.readStringFromUri, diagnosticHandler,
                        <String>['--preserve-comments']);
   result.then((MirrorSystem mirrors) {
     test(mirrors);
   }).then(asyncSuccess);
 }
 
 void test(MirrorSystem mirrors) {
@@ skipping 925 matching lines @@
   Expect.isTrue(privateFactoryConstructor.isPrivate);
   Expect.isFalse(privateFactoryConstructor.isConstConstructor);
   Expect.isFalse(privateFactoryConstructor.isRedirectingConstructor);
   Expect.isFalse(privateFactoryConstructor.isGenerativeConstructor);
   Expect.isTrue(privateFactoryConstructor.isFactoryConstructor);
 
   var metadata = privateClass.metadata;
   Expect.isNotNull(metadata);
   Expect.equals(0, metadata.length);
 }