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

lib/isolate/frog/isolateimpl.dart

Index: lib/isolate/frog/isolateimpl.dart
diff --git a/frog/lib/isolate.dart b/lib/isolate/frog/isolateimpl.dart
similarity index 58%
rename from frog/lib/isolate.dart
rename to lib/isolate/frog/isolateimpl.dart
index 8b68c1338bfeaed3c511c6423015af2562920dd4..00adae66ea1593042e03e2781a6566872252da88 100644
--- a/frog/lib/isolate.dart
+++ b/lib/isolate/frog/isolateimpl.dart
@@ -2,49 +2,38 @@
 // 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.
 
+#library("isolateimpl");
+
+#import("dart:isolate");
+#import("messages.dart", prefix: 'messages');
+#import("ports.dart", prefix: 'ports');
+#native("natives.js");
+
+/** Implementation of [Isolate2]. */
+class Isolate2Impl implements Isolate2 {
+  SendPort sendPort;
+
+  Isolate2Impl(this.sendPort);
+}
+
 /**
  * A native object that is shared across isolates. This object is visible to all
  * isolates running on the same worker (either UI or background web worker).
  *
  * This is code that is intended to 'escape' the isolate boundaries in order to
- * implement the semantics of friendly isolates in JavaScript. Without this we
- * would have been forced to implement more code (including the top-level event
- * loop) in JavaScript itself.
- */
-GlobalState get _globalState() native "return \$globalState;";
-set _globalState(GlobalState val) native "\$globalState = val;";
-
-/**
- * Wrapper that takes the dart entry point and runs it within an isolate. The
- * frog compiler will inject a call of the form [: startRootIsolate(main); :]
- * when it determines that this wrapping is needed. For single-isolate
- * applications (e.g. hello world), this call is not emitted.
+ * implement the semantics of isolates in JavaScript. Without this we would have
+ * been forced to implement more code (including the top-level event loop) in
+ * JavaScript itself.
  */
-void startRootIsolate(entry) {
-  _globalState = new GlobalState();
-
-  // Don't start the main loop again, if we are in a worker.
-  if (_globalState.isWorker) return;
-  final rootContext = new IsolateContext();
-  _globalState.rootContext = rootContext;
-  _fillStatics(rootContext);
-
-  // BUG(5151491): Setting currentContext should not be necessary, but
-  // because closures passed to the DOM as event handlers do not bind their
-  // isolate automatically we try to give them a reasonable context to live in
-  // by having a "default" isolate (the first one created).
-  _globalState.currentContext = rootContext;
-
-  rootContext.eval(entry);
-  _globalState.topEventLoop.run();
-}
+GlobalState get globalState() native "return \$globalState;";
+set globalState(GlobalState val) native "\$globalState = val;";
 
-void _fillStatics(context) native @"""
+void fillStatics(context) native @"""
   $globals = context.isolateStatics;
   $static_init();
 """;
 
-/** Global state associated with the current worker. See [_globalState]. */
+/** Global state associated with the current worker. See [globalState]. */
 // TODO(sigmund): split in multiple classes: global, thread, main-worker states?
 class GlobalState {
 
@@ -102,7 +91,7 @@ class GlobalState {
   MainWorker mainWorker;
 
   /** Registry of active workers. Only used in the main worker. */
-  Map<int, var> workers;
+  Map<int, Dynamic> workers;
 
   GlobalState() {
     topEventLoop = new EventLoop();
@@ -137,7 +126,7 @@ class GlobalState {
     if (isWorker) {
       if (!isolates.isEmpty()) return;
       mainWorker.postMessage(
-          _serializeMessage({'command': 'close'}));
+          messages.serialize({'command': 'close'}));
     } else if (isolates.containsKey(rootContext.id) && workers.isEmpty() &&
                !supportsWorkers && !inWindow) {
       // This should only trigger when running on the command-line.
@@ -148,51 +137,6 @@ class GlobalState {
   }
 }
 
-_serializeMessage(message) {
-  if (_globalState.needSerialization) {
-    return new Serializer().traverse(message);
-  } else {
-    return new Copier().traverse(message);
-  }
-}
-
-_deserializeMessage(message) {
-  if (_globalState.needSerialization) {
-    return new Deserializer().deserialize(message);
-  } else {
-    // Nothing more to do.
-    return message;
-  }
-}
-
-/** Wait until all ports in a message are resolved. */
-_waitForPendingPorts(var message, void callback()) {
-  final finder = new PendingSendPortFinder();
-  finder.traverse(message);
-  Futures.wait(finder.ports).then((_) => callback());
-}
-
-/** Default worker. */
-class MainWorker {
-  int id = 0;
-  void postMessage(msg) native "return \$globalThis.postMessage(msg);";
-  void set onmessage(f) native "\$globalThis.onmessage = f;";
-  void terminate() {}
-}
-
-/**
- * A web worker. This type is also defined in 'dart:dom', but we define it here
- * to avoid introducing a dependency from corelib to dom. This definition uses a
- * 'hidden' type (* prefix on the native name) to enforce that the type is
- * defined dynamically only when web workers are actually available.
- */
-class _Worker native "*Worker" {
-  get id() native "return this.id;";
-  void set id(i) native "this.id = i;";
-  void set onmessage(f) native "this.onmessage = f;";
-  void postMessage(msg) native "return this.postMessage(msg);";
-}
-
 /** Context information tracked for each isolate. */
 class IsolateContext {
   /** Current isolate id. */
@@ -205,7 +149,7 @@ class IsolateContext {
   var isolateStatics; // native object containing all globals of an isolate.
 
   IsolateContext() {
-    id = _globalState.nextIsolateId++;
+    id = globalState.nextIsolateId++;
     ports = {};
     initGlobals();
   }
@@ -218,14 +162,14 @@ class IsolateContext {
    * is called from JavaScript (see $wrap_call in corejs.dart).
    */
   void eval(Function code) {
-    var old = _globalState.currentContext;
-    _globalState.currentContext = this;
+    var old = globalState.currentContext;
+    globalState.currentContext = this;
     this._setGlobals();
     var result = null;
     try {
       result = code();
     } finally {
-      _globalState.currentContext = old;
+      globalState.currentContext = old;
       if (old != null) old._setGlobals();
     }
     return result;
@@ -242,18 +186,19 @@ class IsolateContext {
       throw new Exception("Registry: ports must be registered only once.");
     }
     ports[portId] = port;
-    _globalState.isolates[id] = this; // indicate this isolate is active
+    globalState.isolates[id] = this; // indicate this isolate is active
   }
 
   /** Unregister a port on this isolate. */
   void unregister(int portId) {
     ports.remove(portId);
     if (ports.isEmpty()) {
-      _globalState.isolates.remove(id); // indicate this isolate is not active
+      globalState.isolates.remove(id); // indicate this isolate is not active
     }
   }
 }
 
+
 /** Represent the event loop on a javascript thread (DOM or worker). */
 class EventLoop {
   Queue<IsolateEvent> events;
@@ -273,7 +218,7 @@ class EventLoop {
   bool runIteration() {
     final event = dequeue();
     if (event == null) {
-      _globalState.closeWorker();
+      globalState.closeWorker();
       return false;
     }
     event.process();
@@ -310,13 +255,13 @@ class EventLoop {
    * this is called from JavaScript (see $wrap_call in corejs.dart).
    */
   void run() {
-    if (!_globalState.isWorker) {
+    if (!globalState.isWorker) {
       _runHelper();
     } else {
       try {
         _runHelper();
       } catch(var e, var trace) {
-        _globalState.mainWorker.postMessage(_serializeMessage(
+        globalState.mainWorker.postMessage(messages.serialize(
             {'command': 'error', 'msg': '$e\n$trace' }));
       }
     }
@@ -336,239 +281,26 @@ class IsolateEvent {
   }
 }
 
-/** Common functionality to all send ports. */
-class BaseSendPort implements SendPort {
-  /** Id for the destination isolate. */
-  final int _isolateId;
-
-  BaseSendPort(this._isolateId);
-
-  ReceivePortSingleShotImpl call(var message) {
-    final result = new ReceivePortSingleShotImpl();
-    this.send(message, result.toSendPort());
-    return result;
-  }
-
-  static void checkReplyTo(SendPort replyTo) {
-    if (replyTo !== null
-        && replyTo is! NativeJsSendPort
-        && replyTo is! WorkerSendPort
-        && replyTo is! BufferingSendPort) {
-      throw new Exception("SendPort.send: Illegal replyTo port type");
-    }
-  }
-
-  // TODO(sigmund): replace the current SendPort.call with the following:
-  //Future call(var message) {
-  //   final completer = new Completer();
-  //   final port = new ReceivePort.singleShot();
-  //   send(message, port.toSendPort());
-  //   port.receive((value, ignoreReplyTo) {
-  //     if (value is Exception) {
-  //       completer.completeException(value);
-  //     } else {
-  //       completer.complete(value);
-  //     }
-  //   });
-  //   return completer.future;
-  //}
-
-  abstract void send(var message, [SendPort replyTo]);
-  abstract bool operator ==(var other);
-  abstract int hashCode();
-}
-
-/** A send port that delivers messages in-memory via native JavaScript calls. */
-class NativeJsSendPort extends BaseSendPort implements SendPort {
-  final ReceivePortImpl _receivePort;
-
-  const NativeJsSendPort(this._receivePort, int isolateId) : super(isolateId);
-
-  void send(var message, [SendPort replyTo = null]) {
-    _waitForPendingPorts([message, replyTo], () {
-      checkReplyTo(replyTo);
-      // Check that the isolate still runs and the port is still open
-      final isolate = _globalState.isolates[_isolateId];
-      if (isolate == null) return;
-      if (_receivePort._callback == null) return;
-
-      // We force serialization/deserialization as a simple way to ensure
-      // isolate communication restrictions are respected between isolates that
-      // live in the same worker. NativeJsSendPort delivers both messages from
-      // the same worker and messages from other workers. In particular,
-      // messages sent from a worker via a WorkerSendPort are received at
-      // [_processWorkerMessage] and forwarded to a native port. In such cases,
-      // here we'll see [_globalState.currentContext == null].
-      final shouldSerialize = _globalState.currentContext != null
-          && _globalState.currentContext.id != _isolateId;
-      var msg = message;
-      var reply = replyTo;
-      if (shouldSerialize) {
-        msg = _serializeMessage(msg);
-        reply = _serializeMessage(reply);
-      }
-      _globalState.topEventLoop.enqueue(isolate, () {
-        if (_receivePort._callback != null) {
-          if (shouldSerialize) {
-            msg = _deserializeMessage(msg);
-            reply = _deserializeMessage(reply);
-          }
-          _receivePort._callback(msg, reply);
-        }
-      }, 'receive ' + message);
-    });
-  }
-
-  bool operator ==(var other) => (other is NativeJsSendPort) &&
-      (_receivePort == other._receivePort);
-
-  int hashCode() => _receivePort._id;
-}
-
-/** A send port that delivers messages via worker.postMessage. */
-class WorkerSendPort extends BaseSendPort implements SendPort {
-  final int _workerId;
-  final int _receivePortId;
-
-  const WorkerSendPort(this._workerId, int isolateId, this._receivePortId)
-      : super(isolateId);
-
-  void send(var message, [SendPort replyTo = null]) {
-    _waitForPendingPorts([message, replyTo], () {
-      checkReplyTo(replyTo);
-      final workerMessage = _serializeMessage({
-          'command': 'message',
-          'port': this,
-          'msg': message,
-          'replyTo': replyTo});
-
-      if (_globalState.isWorker) {
-        // communication from one worker to another go through the main worker:
-        _globalState.mainWorker.postMessage(workerMessage);
-      } else {
-        _globalState.workers[_workerId].postMessage(workerMessage);
-      }
-    });
-  }
-
-  bool operator ==(var other) {
-    return (other is WorkerSendPort) &&
-        (_workerId == other._workerId) &&
-        (_isolateId == other._isolateId) &&
-        (_receivePortId == other._receivePortId);
-  }
-
-  int hashCode() {
-    // TODO(sigmund): use a standard hash when we get one available in corelib.
-    return (_workerId << 16) ^ (_isolateId << 8) ^ _receivePortId;
-  }
-}
-
-/** A port that buffers messages until an underlying port gets resolved. */
-class BufferingSendPort extends BaseSendPort implements SendPort {
-  /** Internal counter to assign unique ids to each port. */
-  static int _idCount = 0;
 
-  /** For implementing equals and hashcode. */
-  final int _id;
-
-  /** Underlying port, when resolved. */
-  SendPort _port;
-
-  /**
-   * Future of the underlying port, so that we can detect when this port can be
-   * sent on messages.
-   */
-  Future<SendPort> _futurePort;
-
-  /** Pending messages (and reply ports). */
-  List pending;
-
-  BufferingSendPort(isolateId, this._futurePort)
-      : super(isolateId), _id = _idCount, pending = [] {
-    _idCount++;
-    _futurePort.then((p) {
-      _port = p;
-      for (final item in pending) {
-        p.send(item['message'], item['replyTo']);
-      }
-      pending = null;
-    });
-  }
-
-  BufferingSendPort.fromPort(isolateId, this._port)
-      : super(isolateId), _id = _idCount {
-    _idCount++;
-  }
-
-  void send(var message, [SendPort replyTo]) {
-    if (_port != null) {
-      _port.send(message, replyTo);
-    } else {
-      pending.add({'message': message, 'replyTo': replyTo});
-    }
-  }
-
-  bool operator ==(var other) => other is BufferingSendPort && _id == other._id;
-  int hashCode() => _id;
-}
-
-/** Default factory for receive ports. */
-class ReceivePortFactory {
-
-  factory ReceivePort() {
-    return new ReceivePortImpl();
-  }
-
-  factory ReceivePort.singleShot() {
-    return new ReceivePortSingleShotImpl();
-  }
-}
-
-/** Implementation of a multi-use [ReceivePort] on top of JavaScript. */
-class ReceivePortImpl implements ReceivePort {
-  int _id;
-  Function _callback;
-  static int _nextFreeId = 1;
-
-  ReceivePortImpl()
-      : _id = _nextFreeId++ {
-    _globalState.currentContext.register(_id, this);
-  }
-
-  void receive(void onMessage(var message, SendPort replyTo)) {
-    _callback = onMessage;
-  }
-
-  void close() {
-    _callback = null;
-    _globalState.currentContext.unregister(_id);
-  }
-
-  SendPort toSendPort() {
-    return new NativeJsSendPort(this, _globalState.currentContext.id);
-  }
+/** Default worker. */
+class MainWorker {
+  int id = 0;
+  void postMessage(msg) native "return \$globalThis.postMessage(msg);";
+  void set onmessage(f) native "\$globalThis.onmessage = f;";
+  void terminate() {}
 }
 
-/** Implementation of a single-shot [ReceivePort]. */
-class ReceivePortSingleShotImpl implements ReceivePort {
-
-  ReceivePortSingleShotImpl() : _port = new ReceivePortImpl() { }
-
-  void receive(void callback(var message, SendPort replyTo)) {
-    _port.receive((var message, SendPort replyTo) {
-      _port.close();
-      callback(message, replyTo);
-    });
-  }
-
-  void close() {
-    _port.close();
-  }
-
-  SendPort toSendPort() => _port.toSendPort();
-
-  final ReceivePortImpl _port;
+/**
+ * A web worker. This type is also defined in 'dart:dom', but we define it here
+ * to avoid introducing a dependency from corelib to dom. This definition uses a
+ * 'hidden' type (* prefix on the native name) to enforce that the type is
+ * defined dynamically only when web workers are actually available.
+ */
+class _Worker native "*Worker" {
+  get id() native "return this.id;";
+  void set id(i) native "this.id = i;";
+  void set onmessage(f) native "this.onmessage = f;";
+  void postMessage(msg) native "return this.postMessage(msg);";
 }
 
 final String _SPAWNED_SIGNAL = "spawned";
@@ -586,7 +318,7 @@ class IsolateNatives {
 
     // TODO(floitsch): throw exception if isolate's class doesn't have a
     // default constructor.
-    if (_globalState.useWorkers && !isLight) {
+    if (globalState.useWorkers && !isLight) {
       _startWorker(isolate, port.toSendPort());
     } else {
       _startNonWorker(isolate, port.toSendPort());
@@ -597,13 +329,13 @@ class IsolateNatives {
 
   static SendPort _startWorker(Isolate runnable, SendPort replyPort) {
     var factoryName = _getJSConstructorName(runnable);
-    if (_globalState.isWorker) {
-      _globalState.mainWorker.postMessage(_serializeMessage({
+    if (globalState.isWorker) {
+      globalState.mainWorker.postMessage(messages.serialize({
           'command': 'spawn-worker',
           'factoryName': factoryName,
-          'replyPort': _serializeMessage(replyPort)}));
+          'replyPort': messages.serialize(replyPort)}));
     } else {
-      _spawnWorker(factoryName, _serializeMessage(replyPort));
+      _spawnWorker(factoryName, messages.serialize(replyPort));
     }
   }
 
@@ -647,11 +379,11 @@ class IsolateNatives {
   static void _spawnWorker(factoryName, serializedReplyPort) {
     final worker = _newWorker(_thisScript);
     worker.onmessage = (e) { _processWorkerMessage(worker, e); };
-    var workerId = _globalState.nextWorkerId++;
+    var workerId = globalState.nextWorkerId++;
     // We also store the id on the worker itself so that we can unregister it.
     worker.id = workerId;
-    _globalState.workers[workerId] = worker;
-    worker.postMessage(_serializeMessage({
+    globalState.workers[workerId] = worker;
+    worker.postMessage(messages.serialize({
       'command': 'start',
       'id': workerId,
       'replyTo': serializedReplyPort,
@@ -670,28 +402,28 @@ class IsolateNatives {
    * pass messages along to the isolate running in the worker.
    */
   static void _processWorkerMessage(sender, e) {
-    var msg = _deserializeMessage(_getEventData(e));
+    var msg = messages.deserialize(_getEventData(e));
     switch (msg['command']) {
       // TODO(sigmund): delete after we migrate to Isolate2
       case 'start':
-        _globalState.currentWorkerId = msg['id'];
+        globalState.currentWorkerId = msg['id'];
         var runnerObject =
             _allocate(_getJSConstructorFromName(msg['factoryName']));
         var serializedReplyTo = msg['replyTo'];
-        _globalState.topEventLoop.enqueue(new IsolateContext(), function() {
-          var replyTo = _deserializeMessage(serializedReplyTo);
+        globalState.topEventLoop.enqueue(new IsolateContext(), function() {
+          var replyTo = messages.deserialize(serializedReplyTo);
           _startIsolate(runnerObject, replyTo);
         }, 'worker-start');
-        _globalState.topEventLoop.run();
+        globalState.topEventLoop.run();
         break;
       case 'start2':
-        _globalState.currentWorkerId = msg['id'];
+        globalState.currentWorkerId = msg['id'];
         Function entryPoint = _getJSFunctionFromName(msg['functionName']);
-        var replyTo = _deserializeMessage(msg['replyTo']);
-        _globalState.topEventLoop.enqueue(new IsolateContext(), function() {
+        var replyTo = messages.deserialize(msg['replyTo']);
+        globalState.topEventLoop.enqueue(new IsolateContext(), function() {
           _startIsolate2(entryPoint, replyTo);
         }, 'worker-start');
-        _globalState.topEventLoop.run();
+        globalState.topEventLoop.run();
         break;
       // TODO(sigmund): delete after we migrate to Isolate2
       case 'spawn-worker':
@@ -702,21 +434,21 @@ class IsolateNatives {
         break;
       case 'message':
         msg['port'].send(msg['msg'], msg['replyTo']);
-        _globalState.topEventLoop.run();
+        globalState.topEventLoop.run();
         break;
       case 'close':
         _log("Closing Worker");
-        _globalState.workers.remove(sender.id);
+        globalState.workers.remove(sender.id);
         sender.terminate();
-        _globalState.topEventLoop.run();
+        globalState.topEventLoop.run();
         break;
       case 'log':
         _log(msg['msg']);
         break;
       case 'print':
-        if (_globalState.isWorker) {
-          _globalState.mainWorker.postMessage(
-              _serializeMessage({'command': 'print', 'msg': msg}));
+        if (globalState.isWorker) {
+          globalState.mainWorker.postMessage(
+              messages.serialize({'command': 'print', 'msg': msg}));
         } else {
           print(msg['msg']);
         }
@@ -728,9 +460,9 @@ class IsolateNatives {
 
   /** Log a message, forwarding to the main worker if appropriate. */
   static _log(msg) {
-    if (_globalState.isWorker) {
-      _globalState.mainWorker.postMessage(
-          _serializeMessage({'command': 'log', 'msg': msg }));
+    if (globalState.isWorker) {
+      globalState.mainWorker.postMessage(
+          messages.serialize({'command': 'log', 'msg': msg }));
     } else {
       try {
         _consoleLog(msg);
@@ -781,14 +513,14 @@ class IsolateNatives {
     // isolate. This way, we do not get cross-isolate references
     // through the runnable.
     final ctor = _getJSConstructor(runnable);
-    _globalState.topEventLoop.enqueue(spawned, function() {
+    globalState.topEventLoop.enqueue(spawned, function() {
       _startIsolate(_allocate(ctor), replyTo);
     }, 'nonworker start');
   }
 
   /** Given a ready-to-start runnable, start running it. */
   static void _startIsolate(Isolate isolate, SendPort replyTo) {
-    _fillStatics(_globalState.currentContext);
+    fillStatics(globalState.currentContext);
     ReceivePort port = new ReceivePort();
     replyTo.send(_SPAWNED_SIGNAL, port.toSendPort());
     isolate._run(port);
@@ -806,19 +538,19 @@ class IsolateNatives {
 
     SendPort signalReply = port.toSendPort();
 
-    if (_globalState.useWorkers && !isLight) {
+    if (globalState.useWorkers && !isLight) {
       _startWorker2(functionName, uri, signalReply);
     } else {
       _startNonWorker2(functionName, uri, signalReply);
     }
-    return new BufferingSendPort(
-        _globalState.currentContext.id, completer.future);
+    return new ports.BufferingSendPort(
+        globalState.currentContext.id, completer.future);
   }
 
   static SendPort _startWorker2(
       String functionName, String uri, SendPort replyPort) {
-    if (_globalState.isWorker) {
-      _globalState.mainWorker.postMessage(_serializeMessage({
+    if (globalState.isWorker) {
+      globalState.mainWorker.postMessage(messages.serialize({
           'command': 'spawn-worker2',
           'functionName': functionName,
           'uri': uri,
@@ -833,14 +565,14 @@ class IsolateNatives {
     // TODO(eub): support IE9 using an iframe -- Dart issue 1702.
     if (uri != null) throw new UnsupportedOperationException(
             "Currently Isolate2.fromUri is not supported without web workers.");
-    _globalState.topEventLoop.enqueue(new IsolateContext(), function() {
+    globalState.topEventLoop.enqueue(new IsolateContext(), function() {
       final func = _getJSFunctionFromName(functionName);
       _startIsolate2(func, replyPort);
     }, 'nonworker start');
   }
 
   static void _startIsolate2(Function topLevel, SendPort replyTo) {
-    _fillStatics(_globalState.currentContext);
+    fillStatics(globalState.currentContext);
     final port = new ReceivePort();
     replyTo.send(_SPAWNED_SIGNAL, port.toSendPort());
     topLevel(port);
@@ -856,42 +588,18 @@ class IsolateNatives {
     if (uri == null) uri = _thisScript;
     final worker = _newWorker(uri);
     worker.onmessage = (e) { _processWorkerMessage(worker, e); };
-    var workerId = _globalState.nextWorkerId++;
+    var workerId = globalState.nextWorkerId++;
     // We also store the id on the worker itself so that we can unregister it.
     worker.id = workerId;
-    _globalState.workers[workerId] = worker;
-    worker.postMessage(_serializeMessage({
+    globalState.workers[workerId] = worker;
+    worker.postMessage(messages.serialize({
       'command': 'start2',
       'id': workerId,
       // Note: we serialize replyPort twice because the child worker needs to
       // first deserialize the worker id, before it can correctly deserialize
       // the port (port deserialization is sensitive to what is the current
       // workerId).
-      'replyTo': _serializeMessage(replyPort),
+      'replyTo': messages.serialize(replyPort),
       'functionName': functionName }));
   }
 }
-
-class Isolate2Impl implements Isolate2 {
-  SendPort sendPort;
-
-  Isolate2Impl(this.sendPort);
-
-  void stop() {}
-}
-
-class IsolateFactory implements Isolate2 {
-
-  factory Isolate2.fromCode(Function topLevelFunction) {
-    final name = IsolateNatives._getJSFunctionName(topLevelFunction);
-    if (name == null) {
-      throw new UnsupportedOperationException(
-          "only top-level functions can be spawned.");
-    }
-    return new Isolate2Impl(IsolateNatives._spawn2(name, null, false));
-  }
-
-  factory Isolate2.fromUri(String uri) {
-    return new Isolate2Impl(IsolateNatives._spawn2(null, uri, false));
-  }
-}