Implement port equality on SendPortSync

sdk/lib/html/dart2js/html_dart2js.dart

 library html;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:html_common';
 import 'dart:indexed_db';
 import 'dart:isolate';
 import 'dart:json' as json;
 import 'dart:math';
 import 'dart:svg' as svg;
@@ skipping 25719 matching lines @@
 
   num _id;
   _JsSendPortSync(this._id);
 
   callSync(var message) {
     var serialized = _serialize(message);
     var result = _callPortSync(_id, serialized);
     return _deserialize(result);
   }
 
+  bool operator==(var other) {
+    return (other is _JsSendPortSync) && (_id == other._id);
+  }
+
+  int get hashCode => _id;
 }
 
 // TODO(vsm): Differentiate between Dart2Js and Dartium isolates.
 // The receiver is a different Dart isolate, compiled to JS.
 class _RemoteSendPortSync implements SendPortSync {
 
   int _isolateId;
   int _portId;
   _RemoteSendPortSync(this._isolateId, this._portId);
 
@@ skipping 10 matching lines @@
     var source = '$target-result';
     var result = null;
     var listener = (Event e) {
       result = json.parse(_getPortSyncEventData(e));
     };
     window.on[source].add(listener);
     _dispatchEvent(target, [source, message]);
     window.on[source].remove(listener);
     return result;
   }
+
+  bool operator==(var other) {
+    return (other is _RemoteSendPortSync) && (_isolateId == other._isolateId)
+      && (_portId == other._portId);
+  }
+
+  int get hashCode => _isolateId >> 16 + _portId;
 }
 
 // The receiver is in the same Dart isolate, compiled to JS.
 class _LocalSendPortSync implements SendPortSync {
 
   ReceivePortSync _receivePort;
 
   _LocalSendPortSync._internal(this._receivePort);
 
   callSync(var message) {
     // TODO(vsm): Do a more efficient deep copy.
     var copy = _deserialize(_serialize(message));
     var result = _receivePort._callback(copy);
     return _deserialize(_serialize(result));
   }
+
+  bool operator==(var other) {
+    return (other is _LocalSendPortSync)
+      && (_receivePort == other._receivePort);
+  }
+
+  int get hashCode => _receivePort.hashCode;
 }
 
 // TODO(vsm): Move this to dart:isolate.  This will take some
 // refactoring as there are dependences here on the DOM.  Users
 // interact with this class (or interface if we change it) directly -
 // new ReceivePortSync.  I think most of the DOM logic could be
 // delayed until the corresponding SendPort is registered on the
 // window.
 
 // A Dart ReceivePortSync (tagged 'dart' when serialized) is
@@ skipping 1142 matching lines @@
       _position = nextPosition;
       return true;
     }
     _current = null;
     _position = _array.length;
     return false;
   }
 
   T get current => _current;
 }