Re-apply "Clean up the patch file for the isolate library by introducing a new buitlin library: iso…

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 'dart:uri';
 import 'parser_helper.dart';
 import 'mock_compiler.dart';
 import '../../../sdk/lib/_internal/compiler/compiler.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/dart2jslib.dart' as leg;
 import '../../../sdk/lib/_internal/compiler/implementation/dart_backend/dart_backend.dart';
@@ skipping 43 matching lines @@
 
 const helperLib = r'''
 library js_helper;
 class JSInvocationMirror {}
 ''';
 
 const foreignLib = r'''
 var JS;
 ''';
 
+const isolateHelperLib = r'''
+class _WorkerStub {
+}
+''';
+
 testDart2Dart(String src, {void continuation(String s), bool minify: false,
     bool stripTypes: false}) {
   // If continuation is not provided, check that source string remains the same.
   if (continuation == null) {
     continuation = (s) { Expect.equals(src, s); };
   }
   testDart2DartWithLibrary(src, '', continuation: continuation, minify: minify,
       stripTypes: stripTypes);
 }
 
 /**
  * Library name is assumed to be 'mylib' in 'mylib.dart' file.
  */
 testDart2DartWithLibrary(
     String srcMain, String srcLibrary,
     {void continuation(String s), bool minify: false,
     bool stripTypes: false}) {
   fileUri(path) => new Uri.fromComponents(scheme: 'file', path: path);
 
   final scriptUri = fileUri('script.dart');
   final libUri = fileUri('mylib.dart');
 
   provider(uri) {
     if (uri == scriptUri) return new Future.immediate(srcMain);
     if (uri.toString() == libUri.toString()) {
       return new Future.immediate(srcLibrary);
     }
-    if (uri.path.endsWith('/core.dart')) return new Future.immediate(coreLib);
-    if (uri.path.endsWith('/io.dart')) return new Future.immediate(ioLib);
-    if (uri.path.endsWith('/js_helper.dart')) return new Future.immediate(helperLib);
-    // TODO(smok): The file should change to html_dartium at some point.
-    if (uri.path.endsWith('/html_dart2js.dart')) return new Future.immediate(htmlLib);
-    if (uri.path.endsWith('/foreign_helper.dart')) return new Future.immediate(foreignLib);
+    if (uri.path.endsWith('/core.dart')) {
+      return new Future.immediate(coreLib);
+    } else  if (uri.path.endsWith('/io.dart')) {
+      return new Future.immediate(ioLib);
+    } else if (uri.path.endsWith('/js_helper.dart')) {
+      return new Future.immediate(helperLib);
+    } else if (uri.path.endsWith('/html_dart2js.dart')) {
+      // TODO(smok): The file should change to html_dartium at some point.
+      return new Future.immediate(htmlLib);
+    } else if (uri.path.endsWith('/foreign_helper.dart')) {
+      return new Future.immediate(foreignLib);
+    } else if (uri.path.endsWith('/isolate_helper.dart')) {
+      return new Future.immediate(isolateHelperLib);
+    }
     return new Future.immediate('');
   }
 
   handler(uri, begin, end, message, kind) {
     if (identical(kind, Diagnostic.ERROR) || identical(kind, Diagnostic.CRASH)) {
       Expect.fail('$uri: $begin-$end: $message [$kind]');
     }
   }
 
   final options = <String>['--output-type=dart'];
@@ skipping 631 matching lines @@
   testStaticAccessIoLib();
   testLocalFunctionPlaceholder();
   testMinification();
   testClosureLocalsMinified();
   testParametersMinified();
   testDeclarationTypePlaceholders();
   testPlatformLibraryMemberNamesAreFixed();
   testConflictsWithCoreLib();
   testUnresolvedNamedConstructor();
 }