Very simple version of Isolates.

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 3524d71d498f9b03b90ad9e54ed790521a0450b5..93b658fe576412e5acf8b13fdb3b59d1625e6f7e 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -3672,22 +3672,24 @@ TEST_CASE(NegativeNativeFieldInIsolateMessage) {
   const char* kScriptChars =
       "import 'dart:isolate';\n"
       "import 'dart:nativewrappers';\n"
-      "echo() {\n"
-      "  port.receive((msg, reply) {\n"
-      "    reply.send('echoing ${msg(1)}}');\n"
-      "  });\n"
+      "echo(msg) {\n"
+      "  var data = msg[0];\n"
+      "  var reply = msg[1];\n"
+      "  reply.send('echoing ${data(1)}}');\n"
       "}\n"
       "class Test extends NativeFieldWrapperClass2 {\n"
       "  Test(this.i, this.j);\n"
       "  int i, j;\n"
       "}\n"
       "main() {\n"
-      "  var snd = spawnFunction(echo);\n"
+      "  var port = new RawReceivePort();\n"
       "  var obj = new Test(1,2);\n"
-      "  snd.send(obj, port.toSendPort());\n"
-      "  port.receive((msg, reply) {\n"
+      "  var msg = [obj, port.sendPort];\n"
+      "  var snd = Isolate.spawn(echo, msg);\n"
+      "  port.handler = (msg) {\n"
+      "    port.close();\n"
       "    print('from worker ${msg}');\n"
-      "  });\n"
+      "  };\n"
       "}\n";
 
   DARTSCOPE(Isolate::Current());
@@ -5780,12 +5782,12 @@ UNIT_TEST_CASE(NewNativePort) {
   const char* kScriptChars =
       "import 'dart:isolate';\n"
       "void callPort(SendPort port) {\n"
-      "  var receivePort = new ReceivePort();\n"
-      "  port.send(null, receivePort.toSendPort());\n"
-      "  receivePort.receive((message, _) {\n"
+      "  var receivePort = new RawReceivePort();\n"
+      "  port.send(null, receivePort.sendPort);\n"
+      "  receivePort.handler = (message) {\n"
       "    receivePort.close();\n"
       "    throw new Exception(message);\n"
-      "  });\n"
+      "  };\n"
       "}\n";
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   Dart_EnterScope();
@@ -5834,26 +5836,24 @@ static Dart_Isolate RunLoopTestCallback(const char* script_name,
   const char* kScriptChars =
       "import 'builtin';\n"
       "import 'dart:isolate';\n"
-      "void entry() {\n"
-      "  port.receive((message, replyTo) {\n"
-      "    if (message) {\n"
-      "      throw new Exception('MakeChildExit');\n"
-      "    } else {\n"
-      "      replyTo.call('hello');\n"
-      "      port.close();\n"
-      "    }\n"
-      "  });\n"
+      "void entry(message) {\n"
+      "  var data = message[0];\n"
+      "  var replyTo = message[1];\n"
+      "  if (data) {\n"
+      "    throw new Exception('MakeChildExit');\n"
+      "  } else {\n"
+      "    replyTo.send('hello');\n"
+      "  }\n"
       "}\n"
       "\n"
       "void main(exc_child, exc_parent) {\n"
-      "  var port = spawnFunction(entry);\n"
-      "  var receivePort = new ReceivePort();\n"
-      "  port.send(exc_child, receivePort.toSendPort());\n"
-      "  receivePort.receive((message, _) {\n"
+      "  var receivePort = new RawReceivePort();\n"
+      "  Isolate.spawn(entry, [exc_child, receivePort.sendPort]);\n"
+      "  receivePort.handler = (message) {\n"
       "    receivePort.close();\n"
       "    if (message != 'hello') throw new Exception('ShouldNotHappen');\n"
       "    if (exc_parent) throw new Exception('MakeParentExit');\n"
-      "  });\n"
+      "  };\n"
       "}\n";
 
   if (Dart_CurrentIsolate() != NULL) {