Add dart2js unittest to analyze the API.

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';
+import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart'
+    hide Compiler;
+import '../../../sdk/lib/_internal/compiler/implementation/filenames.dart';
+import '../../../sdk/lib/_internal/compiler/implementation/source_file_provider.dart';
+import '../../../sdk/lib/_internal/libraries.dart';
+
+class CollectingDiagnosticHandler extends FormattingDiagnosticHandler {
+  bool hasWarnings = false;
+  bool hasErrors = false;
+
+  CollectingDiagnosticHandler(SourceFileProvider provider) : super(provider);
+
+  void diagnosticHandler(Uri uri, int begin, int end, String message,
+                         api.Diagnostic kind) {
+    if (kind == api.Diagnostic.WARNING) {
+      hasWarnings = true;
+    }
+    if (kind == api.Diagnostic.ERROR) {
+      hasErrors = true;
+    }
+    super.diagnosticHandler(uri, begin, end, message, kind);
+  }
+}
+
+void main() {
+  Uri currentWorkingDirectory = getCurrentDirectory();
+  var libraryRoot = currentWorkingDirectory.resolve('sdk/');
+  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,
+      handler.diagnosticHandler,
+      libraryRoot, libraryRoot,
+      <String>['--analyze-only']);
+  compiler.librariesToAnalyzeWhenRun = uriList;
+  compiler.run(null);
+  Expect.isFalse(handler.hasWarnings);
+  Expect.isFalse(handler.hasErrors);
+}