Remove scanBuiltinLibraries.

tests/compiler/dart2js/dart_backend_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 'dart:async';
 import "package:async_helper/async_helper.dart";
 import 'mock_compiler.dart';
 import '../../../sdk/lib/_internal/compiler/compiler.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart' as leg;
@@ skipping 26 matching lines @@
   factory LinkedHashMap._literal(elements) => null;
 }
 class Math {
   static double parseDouble(String s) => 1.0;
 }
 print(x) {}
 identical(a, b) => true;
 const proxy = 0;
 ''';
 
+const corePatch = r'''
+import 'dart:_js_helper';
+import 'dart:_interceptors';
+import 'dart:_isolate_helper';
+import 'dart:_foreign_helper';
+''';
+
 const ioLib = r'''
 library io;
 class Platform {
   static int operatingSystem;
 }
 ''';
 
 const htmlLib = r'''
 library html;
 Window __window;
 Window get window => __window;
 abstract class Window {
   Navigator get navigator;
 }
 abstract class Navigator {
   String get userAgent;
 }
 ''';
 
 const helperLib = r'''
 library js_helper;
 class JSInvocationMirror {}
 assertHelper(a) {}
+class Closure {}
+class BoundClosure {}
 ''';
 
 const foreignLib = r'''
 var JS;
 ''';
 
 const isolateHelperLib = r'''
 class _WorkerStub {
 }
 ''';
@@ skipping 20 matching lines @@
   final scriptUri = fileUri('script.dart');
   final libUri = fileUri('mylib.dart');
 
   provider(uri) {
     if (uri == scriptUri) return new Future.value(srcMain);
     if (uri.toString() == libUri.toString()) {
       return new Future.value(srcLibrary);
     }
     if (uri.path.endsWith('/core.dart')) {
       return new Future.value(coreLib);
-    } else  if (uri.path.endsWith('/io.dart')) {
+    } else if (uri.path.endsWith('/core_patch.dart')) {
+      return new Future.value(corePatch);
+    } else if (uri.path.endsWith('/io.dart')) {
       return new Future.value(ioLib);
     } else if (uri.path.endsWith('/js_helper.dart')) {
       return new Future.value(helperLib);
     } else if (uri.path.endsWith('/html_dart2js.dart')) {
       // TODO(smok): The file should change to html_dartium at some point.
       return new Future.value(htmlLib);
     } else if (uri.path.endsWith('/foreign_helper.dart')) {
       return new Future.value(foreignLib);
     } else if (uri.path.endsWith('/isolate_helper.dart')) {
       return new Future.value(isolateHelperLib);
@@ skipping 618 matching lines @@
   testStaticAccessIoLib();
   testLocalFunctionPlaceholder();
   testMinification();
   testClosureLocalsMinified();
   testParametersMinified();
   testDeclarationTypePlaceholders();
   testPlatformLibraryMemberNamesAreFixed();
   testConflictsWithCoreLib();
   testUnresolvedNamedConstructor();
 }