Fix Observatory by disabling WebSocket compression

runtime/bin/vmservice/server.dart

 // Copyright (c) 2013, 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.
 
 part of vmservice_io;
 
 class WebSocketClient extends Client {
   static const int PARSE_ERROR_CODE = 4000;
   static const int BINARY_MESSAGE_ERROR_CODE = 4001;
   static const int NOT_MAP_ERROR_CODE = 4002;
@@ skipping 112 matching lines @@
     if (request.method != 'GET') {
       // Not a GET request. Do nothing.
       request.response.close();
       return;
     }
 
     final String path =
           request.uri.path == '/' ? ROOT_REDIRECT_PATH : request.uri.path;
 
     if (path == WEBSOCKET_PATH) {
-      WebSocketTransformer.upgrade(request).then((WebSocket webSocket) {
+      WebSocketTransformer.upgrade(request,
+                                   compression: CompressionOptions.OFF).then(
+                                   (WebSocket webSocket) {
         new WebSocketClient(webSocket, _service);
       });
       return;
     }
 
     Asset asset = assets[path];
     if (asset != null) {
       // Serving up a static asset (e.g. .css, .html, .png).
       request.response.headers.contentType =
           ContentType.parse(asset.mimeType);
@@ skipping 70 matching lines @@
       print('Could not shutdown Observatory HTTP server:\n$e\n$st\n');
       _notifyServerState("", 0);
       return this;
     });
   }
 
 }
 
 void _notifyServerState(String ip, int port)
     native "VMServiceIO_NotifyServerState";