Make event-handlers edge-triggered and move socket-state to Dart.

sdk/lib/io/websocket_impl.dart

Index: sdk/lib/io/websocket_impl.dart
diff --git a/sdk/lib/io/websocket_impl.dart b/sdk/lib/io/websocket_impl.dart
index b169afac76c40f4d8f8a88b695b861e6599c162f..ee56378d788a279caf39372d7084f05931c712b9 100644
--- a/sdk/lib/io/websocket_impl.dart
+++ b/sdk/lib/io/websocket_impl.dart
@@ -781,6 +781,7 @@ class _WebSocketImpl extends Stream implements WebSocket {
 
   int _outCloseCode;
   String _outCloseReason;
+  Timer _closeTimer;
 
   static final HttpClient _httpClient = new HttpClient();
 
@@ -879,6 +880,7 @@ class _WebSocketImpl extends Stream implements WebSocket {
           }
         },
         onError: (error) {
+          if (_closeTimer != null) _closeTimer.cancel();
           if (error is FormatException) {
             _close(WebSocketStatus.INVALID_FRAME_PAYLOAD_DATA);
           } else {
@@ -887,6 +889,7 @@ class _WebSocketImpl extends Stream implements WebSocket {
           _controller.close();
         },
         onDone: () {
+          if (_closeTimer != null) _closeTimer.cancel();
           if (_readyState == WebSocket.OPEN) {
             _readyState = WebSocket.CLOSING;
             if (!_isReservedStatusCode(transformer.closeCode)) {
@@ -957,6 +960,13 @@ class _WebSocketImpl extends Stream implements WebSocket {
       _outCloseCode = code;
       _outCloseReason = reason;
     }
+    if (_closeTimer == null && !_controller.isClosed) {
+      // When closing the web-socket, we no longer accept data.
+      _closeTimer = new Timer(const Duration(seconds: 5), () {
+        _subscription.cancel();
+        _controller.close();
+      });
+    }
     return _sink.close();
   }