isolates refactor: this change introduces 'dart:isolate' as a library. This is a

frog/world.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.
 
 /** The one true [World]. */
 World world;
 
 /**
  * Experimental phase to enable await, only set when using the
  * await/awaitc.dart entrypoint.
@@ skipping 86 matching lines @@
 
   FileSystem files;
   final LibraryReader reader;
 
   Map<String, Library> libraries;
   Library corelib;
   Library coreimpl;
 
   // TODO(jmesserly): we shouldn't be special casing DOM anywhere.
   Library dom;
+  Library isolatelib;
 
   List<Library> _todo;
 
   /** Internal map to track name conflicts in the generated javascript. */
   Map<String, Element> _topNames;
 
   Map<String, MemberSet> _members;
 
   MessageHandler messageHandler;
 
@@ skipping 336 matching lines @@
       info('read library ${filename}');
       if (!library.isCore &&
           !library.imports.some((li) => li.library.isCore)) {
         library.imports.add(new LibraryImport(corelib));
       }
       libraries[filename] = library;
       _todo.add(library);
 
       if (filename == 'dart:dom') {
         dom = library;
+      } else if (filename == 'dart:isolate') {
+        isolatelib = library;
       }
     }
     return library;
   }
 
   process() {
     while (_todo.length > 0) {
       final todo = _todo;
       _todo = [];
       for (var lib in todo) {
@@ skipping 158 matching lines @@
 
   withTiming(String name, f()) {
     final sw = new Stopwatch();
     sw.start();
     var result = f();
     sw.stop();
     info('$name in ${sw.elapsedInMs()}msec');
     return result;
   }
 }