Support proxying of objects between JS and Dart.

lib/html/dart2js/html_dart2js.dart

Index: lib/html/dart2js/html_dart2js.dart
diff --git a/lib/html/dart2js/html_dart2js.dart b/lib/html/dart2js/html_dart2js.dart
index 8dea02e5bc2ef041a587e7f8ecb16ca6676b336b..1d1984fe503fdf9987891cd227a57d6f2a7b97e7 100644
--- a/lib/html/dart2js/html_dart2js.dart
+++ b/lib/html/dart2js/html_dart2js.dart
@@ -37098,6 +37098,12 @@ _serialize(var message) {
   return new _JsSerializer().traverse(message);
 }
 
+class JsProxy {
+  final int _id;
+
+  JsProxy._internal(this._id);
+}
+
 class _JsSerializer extends _Serializer {
 
   visitSendPortSync(SendPortSync x) {
@@ -37123,28 +37129,53 @@ class _JsSerializer extends _Serializer {
 
   visitObject(Object x) {
     if (x is Function) return visitFunction(x);
+    if (x is JsProxy) return visitJsProxy(x);
+
     // TODO: Handle DOM elements and proxy other objects.
-    throw "Unserializable object $x";
+    var proxyId = _makeDartProxyRef(x);
+    return [ 'objref', 'dart', proxyId ];
  }
 
   visitFunction(Function func) {
     return [ 'funcref',
               _makeFunctionRef(func), visitSendPortSync(_sendPort()), null ];
   }
+
+  visitJsProxy(JsProxy proxy) {
+    return [ 'objref', 'nativejs', proxy._id ];
+  }
 }
 
 // Leaking implementation.  Later will be backend specific and hopefully
 // not leaking (at least in most of the cases.)
 // TODO: provide better, backend specific implementation.
-class _FunctionRegistry {
+class _Registry<T> {
+  final String _name;
+  final int _nextId;
+  final Map<String, T> _registry;
+
+  _Registry(this._name) :
+      _nextId = 0,
+      _registry = <T>{};
+
+  String _add(T x) {
+    // TODO(vsm): Cache x and reuse id.
+    final id = '$_name-${_nextId++}';
+    _registry[id] = x;
+    return id;
+  }
+
+  T _get(String id) {
+    return _registry[id];
+  }
+}
+
+class _FunctionRegistry extends _Registry<Function> {
   final ReceivePortSync _port;
-  int _nextId;
-  final Map<String, Function> _registry;
 
   _FunctionRegistry() :
-      _port = new ReceivePortSync(),
-      _nextId = 0,
-      _registry = <Function>{} {
+      super('func-ref'),
+      _port = new ReceivePortSync() {
     _port.receive((msg) {
       final id = msg[0];
       final args = msg[1];
@@ -37160,12 +37191,6 @@ class _FunctionRegistry {
     });
   }
 
-  String _add(Function f) {
-    final id = 'func-ref-${_nextId++}';
-    _registry[id] = f;
-    return id;
-  }
-
   get _sendPort() => _port.toSendPort();
 }
 
@@ -37179,6 +37204,23 @@ _makeFunctionRef(f) => _functionRegistry._add(f);
 _sendPort() => _functionRegistry._sendPort;
 /// End of function serialization implementation.
 
+/// Object proxy implementation.
+
+class _DartProxyRegistry extends _Registry<Object> {
+  _DartProxyRegistry() : super('dart-ref');
+}
+
+_DartProxyRegistry __dartProxyRegistry;
+get _dartProxyRegistry() {
+  if (__dartProxyRegistry === null) __dartProxyRegistry = new _DartProxyRegistry();
+  return __dartProxyRegistry;
+}
+
+_makeDartProxyRef(f) => _dartProxyRegistry._add(f);
+_getDartProxyObj(id) => _dartProxyRegistry._get(id);
+
+/// End of object proxy implementation.
+
 _deserialize(var message) {
   return new _JsDeserializer().deserialize(message);
 }
@@ -37206,6 +37248,7 @@ class _JsDeserializer extends _Deserializer {
     String tag = x[0];
     switch (tag) {
       case 'funcref': return deserializeFunction(x);
+      case 'objref': return deserializeProxy(x);
       default: throw 'Illegal object type: $x';
     }
   }
@@ -37223,6 +37266,21 @@ class _JsDeserializer extends _Deserializer {
       return port.callSync(message);
     };
   }
+
+  deserializeProxy(x) {
+    String tag = x[1];
+    switch (tag) {
+      case 'nativejs':
+        int id = x[2];
+        return new JsProxy._internal(id);
+      case 'dart':
+        int id = x[2];
+        // TODO(vsm): Check for isolate id.  If the isolate isn't the
+        // current isolate, return a DartProxy.
+        return _getDartProxyObj(id);
+      default: throw 'Illegal proxy: $x';
+    }
+  }
 }
 
 // The receiver is JS.