Fix missing functionality with --allow-native-extensions

tests/compiler/dart2js/analyze_only_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.
 
 // Smoke test of the dart2js compiler API.
 library analyze_only;
 
 import "package:expect/expect.dart";
 import 'dart:async';
 import "package:async_helper/async_helper.dart";
 
 import '../../utils/dummy_compiler_test.dart' as dummy;
 import 'package:compiler/compiler.dart';
 import 'package:compiler/src/commandline_options.dart';
-import 'package:compiler/src/diagnostics/messages.dart' show
-    MessageKind, MessageTemplate;
+import 'package:compiler/src/diagnostics/messages.dart'
+    show MessageKind, MessageTemplate;
 
 import 'output_collector.dart';
 
 runCompiler(String main, List<String> options,
             onValue(String code, List errors, List warnings)) {
   List errors = new List();
   List warnings = new List();
 
   Future<String> localProvider(Uri uri) {
     if (uri.scheme != 'main') return dummy.provider(uri);
@@ skipping 141 matching lines @@
   runCompiler(
     "",
     [Flags.analyzeOnly, Flags.analyzeAll],
     (String code, List errors, List warnings) {
       Expect.isNull(code);
       Expect.isTrue(errors.isEmpty);
       Expect.isTrue(warnings.isEmpty);
     });
 
   // --analyze-signatures-only implies --analyze-only
+  runCompiler("", [Flags.analyzeSignaturesOnly, Flags.analyzeAll],
+      (String code, List errors, List warnings) {
+    Expect.isNull(code);
+    Expect.isTrue(errors.isEmpty);
+    Expect.isTrue(warnings.isEmpty);
+  });
+
+  // Test that --allow-native-extensions works.
   runCompiler(
-    "",
-    [Flags.analyzeSignaturesOnly, Flags.analyzeAll],
-    (String code, List errors, List warnings) {
-      Expect.isNull(code);
-      Expect.isTrue(errors.isEmpty);
-      Expect.isTrue(warnings.isEmpty);
-    });
+      """main() {}
+      foo() native 'foo';""",
+      [Flags.analyzeOnly, Flags.allowNativeExtensions],
+      (String code, List errors, List warnings) {
+    Expect.isNull(code);
+    Expect.isTrue(errors.isEmpty);
+    Expect.isTrue(warnings.isEmpty);
+  });
+  runCompiler(
+      """main() {}
+      foo() native 'foo';""",
+      [Flags.analyzeOnly],
+      (String code, List errors, List warnings) {
+    Expect.isNull(code);
+    Expect.isTrue(
+        errors.single.startsWith("'native' modifier is not supported."));
+    Expect.isTrue(warnings.isEmpty);
+  });
 }