Fix closing of server sockets.

runtime/bin/http_impl.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.
 
 class _HttpHeaders implements HttpHeaders {
   _HttpHeaders() : _headers = new Map<String, List<String>>();
 
   List<String> operator[](String name) {
     name = name.toLowerCase();
     return _headers[name];
@@ skipping 672 matching lines @@
     bool allWritten = true;
     if (_contentLength < 0) {
       // Terminate the content if transfer encoding is chunked.
       allWritten = _httpConnection._write(_Const.END_CHUNKED);
     } else {
       if (!_headResponse && _bodyBytesWritten < _contentLength) {
         throw new HttpException("Sending less than specified content length");
       }
       assert(_headResponse || _bodyBytesWritten == _contentLength);
     }
-    if (!persistentConnection) _httpConnection._close();
+    // If we are done writing the response and the client has closed
+    // or the connection is not persistent we can close.
+    if (!persistentConnection || _httpConnection._closing) {
+      _httpConnection._close();
+    }
     return allWritten;
   }
 
   bool _writeHeaders() {
     _headers._mutable = false;
     _headers._write(_httpConnection);
     // Terminate header.
     return _writeCRLF();
   }
 
@@ skipping 638 matching lines @@
       onError(e);
       // Propagate the error to the streams.
       if (_request != null && _request._streamErrorHandler != null) {
         _request._streamErrorHandler(e);
       }
       if (_response != null && _response._streamErrorHandler != null) {
         _response._streamErrorHandler(e);
       }
     }
 
-    // If currently not processing any request just close the socket.
+    // If currently not processing any request close the socket when
+    // we are done writing the response.
     if (_httpParser.isIdle) {
       _socket.outputStream.onClosed = () {
         _destroy();
         if (onClosed != null && e == null) {
           // Don't call onClosed if onError has been called.
           onClosed();
         }
       };
+      // If the client closes and we are done writing the response
+      // the connection should be closed.
+      if (_response == null) _close();
       return;
     }
 
     // Processing a request.
     if (e == null) {
       // Indicate connection close to the HTTP parser.
       _httpParser.connectionClosed();
     }
   }
 
@@ skipping 800 matching lines @@
 
 
 class _RedirectInfo implements RedirectInfo {
   const _RedirectInfo(int this.statusCode,
                       String this.method,
                       Uri this.location);
   final int statusCode;
   final String method;
   final Uri location;
 }