Rank most retaining instances for each class.

runtime/observatory/lib/service_common.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_common;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:typed_data';
 
@@ skipping 154 matching lines @@
     _sendAllDelayedRequests();
     _notifyConnect();
   }
 
   // WebSocket message event handler.
   void _onMessage(dynamic data) {
     if (data is! String) {
       _webSocket.nonStringToByteData(data).then((ByteData bytes) {
         // See format spec. in VMs Service::SendEvent.
         int offset = 0;
-        int metaSize = bytes.getUint64(offset, Endianness.BIG_ENDIAN);
+        // Dart2JS workaround (no getUint64). Limit to 4 GB metadata.
+        assert(bytes.getUint32(offset, Endianness.BIG_ENDIAN) == 0);
+        int metaSize = bytes.getUint32(offset + 4, Endianness.BIG_ENDIAN);
         offset += 8;
         var meta = _utf8Decoder.convert(new Uint8List.view(
             bytes.buffer, bytes.offsetInBytes + offset, metaSize));
         offset += metaSize;
         var data = new ByteData.view(
             bytes.buffer,
             bytes.offsetInBytes + offset,
             bytes.lengthInBytes - offset);
         postEventMessage(meta, data);
       });
@@ skipping 95 matching lines @@
           'query': request.id
         }
       });
     } else {
       message = JSON.encode({'seq': serial, 'request': request.id});
     }
     // Send message.
     _webSocket.send(message);
   }
 }