Don't hide interceptors in mirrors.

tests/compiler/dart2js/mirrors_used_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 that the @MirrorsUsed annotation suppress hints and that only
 /// requested elements are retained for reflection.
 library dart2js.test.mirrors_used_test;
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
@@ skipping 56 matching lines @@
     // The following names should be retained:
     List expectedNames = [
         'Foo', // The name of class Foo.
         r'Foo$', // The name of class Foo's constructor.
         r'get$field']; // The (getter) name of Foo.field.
     // TODO(ahe): Check for the following names, currently they are not being
     // recorded correctly, but are being emitted.
     [
         'Foo_staticMethod', // The name of Foo.staticMethod.
         r'instanceMethod$0']; // The name of Foo.instanceMethod.
+
+    // We always include the names of some native classes.
+    List<Element> nativeClasses = [
+          compiler.intClass, compiler.doubleClass, compiler.numClass,
+          compiler.stringClass, compiler.boolClass, compiler.nullClass,
+          compiler.listClass
+        ];
+
+    Iterable<String> nativeNames =
+        nativeClasses.map(compiler.backend.namer.getNameOfClass);
+    expectedNames.addAll(nativeNames);
+
     Set recordedNames = new Set()
         ..addAll(compiler.backend.emitter.recordedMangledNames)
         ..addAll(compiler.backend.emitter.mangledFieldNames.keys)
         ..addAll(compiler.backend.emitter.mangledGlobalFieldNames.keys);
     Expect.setEquals(new Set.from(expectedNames), recordedNames);
 
     for (var library in compiler.libraries.values) {
       library.forEachLocalMember((member) {
         if (library == compiler.mainApp && member.name == 'Foo') {
           Expect.isTrue(
@@ skipping 63 matching lines @@
 library lib;
 
 import 'dart:mirrors';
 
 useReflect(type) {
   print(new Symbol('Foo'));
   print(MirrorSystem.getName(reflectClass(type).owner.qualifiedName));
 }
 """,
 };