Initial web socket server implementation

runtime/bin/http.dart

Index: runtime/bin/http.dart
diff --git a/runtime/bin/http.dart b/runtime/bin/http.dart
index 41a0ac8bdc6a9380e99d717e97b5b89c713f7a9b..70abec15533a9a7b71d27e9cbf755a2da1cba88b 100644
--- a/runtime/bin/http.dart
+++ b/runtime/bin/http.dart
@@ -383,6 +383,16 @@ interface HttpResponse default _HttpResponse {
    * having retrieved the output stream will throw an exception.
    */
   OutputStream get outputStream();
+
+  /**
+   * Detach the underlying socket from the HTTP server. When the
+   * socket is detached the HTTP server will no longer perform any
+   * operations on it.
+   *
+   * This is normally used when a HTTP upgraded request is received
+   * and the communication should continue with a different protocol.
+   */
+  Socket detachSocket();
 }