Optional binary payloads in VM service events.

runtime/bin/vmservice/observatory/lib/service_html.dart

 // Copyright (c) 2014, 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.
 
 library service_html;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
+import 'dart:typed_data';
 
 import 'package:observatory/service_common.dart';
 
 // Export the service library.
 export 'package:observatory/service_common.dart';
 
 class _HtmlWebSocket implements CommonWebSocket {
   WebSocket _webSocket;
 
   void connect(String address,
@@ skipping 10 matching lines @@
   
   bool get isOpen => _webSocket.readyState == WebSocket.OPEN;
   
   void send(dynamic data) {
     _webSocket.send(data);
   }
   
   void close() {
     _webSocket.close();
   }
+  
+  Future<ByteData> nonStringToByteData(dynamic data) {
+    assert(data is Blob);
+    FileReader fileReader = new FileReader();
+    fileReader.readAsArrayBuffer(data);
+    return fileReader.onLoadEnd.first.then((e)
+        => new ByteData.view(fileReader.result));
+  }
 }
 
 /// The [WebSocketVM] communicates with a Dart VM over WebSocket. The Dart VM
 /// can be embedded in Chromium or standalone. In the case of Chromium, we
 /// make the service requests via the Chrome Remote Debugging Protocol.
 class WebSocketVM extends CommonWebSocketVM {
   WebSocketVM(WebSocketVMTarget target) : super(target, new _HtmlWebSocket());
 }
 
 // A VM that communicates with the service via posting messages from DevTools.
@@ skipping 31 matching lines @@
     message['id'] = idString;
     message['method'] = 'observatoryQuery';
     message['query'] = '$path';
     _requestSerial++;
     var completer = new Completer();
     _pendingRequests[idString] = completer;
     window.parent.postMessage(JSON.encode(message), '*');
     return completer.future;
   }
 }