Support general serializing of functions between JS and Dart

tests/html/js_interop_func_passing_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
 
 #library('JsInteropFuncPassingTest');
 #import('../../pkg/unittest/unittest.dart');
 #import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 #import('dart:isolate');
 
 injectSource(code) {
   final script = new ScriptElement();
   script.type = 'text/javascript';
   script.innerHTML = code;
   document.body.nodes.add(script);
 }
 
-var isolateTest = """
+var dartToJsTest = """
   var port = new ReceivePortSync();
   port.receive(function (f) {
     return f('fromJS');
   });
-  window.registerPort('test', port.toSendPort());
+  window.registerPort('test1', port.toSendPort());
+""";
+
+var jsToDartTest = """
+  var port1 = window.lookupPort('test2a');
+  var result = port1.callSync(function (x) {
+    return x*2;
+  });
+  
+  var port2 = window.lookupPort('test2b');
+  port2.callSync(result);
+""";
+
+var dartToJsToDartTest = """
+  var port = new ReceivePortSync();
+  port.receive(function (f) {
+    return f;
+  });
+  window.registerPort('test3', port.toSendPort());
 """;
 
 main() {
   useHtmlConfiguration();
 
   test('dart-to-js-function', () {
-    injectSource(isolateTest);
+    injectSource(dartToJsTest);
 
-    SendPortSync port = window.lookupPort('test');
+    SendPortSync port = window.lookupPort('test1');
     var result = port.callSync((msg) {
       Expect.equals('fromJS', msg);
       return 'received';
     });
     Expect.equals('received', result);
   });
+
+  test('js-to-dart-function', () {
+    var port1 = new ReceivePortSync();
+    int invoked1 = 0;
+    port1.receive((f) {
+      ++invoked1;
+      var data = f(21);
+      expect(data, equals(42));
+      return 'fromDart';
+    });
+    window.registerPort('test2a', port1.toSendPort());
+
+    var port2 = new ReceivePortSync();
+    int invoked2 = 0;
+    port2.receive((x) {
+      ++invoked2;
+      expect(x, equals('fromDart'));
+    });
+    window.registerPort('test2b', port2.toSendPort());
+
+    injectSource(jsToDartTest);
+
+    expect(1, equals(invoked1));
+    expect(1, equals(invoked2));
+  });
+
+  test('dart-to-js-to-dart-function', () {
+    injectSource(dartToJsToDartTest);
+    
+    validate(x) {
+      expect(x, equals('fromCaller'));
+      return 'fromCallee';
+    }
+
+    SendPortSync port = window.lookupPort('test3');
+    var f = port.callSync(validate);
+    var result = f('fromCaller');
+    Expect.equals('fromCallee', result);
+    
+  });
 }