Make observatory 'pub serve' work again in Dartium

runtime/observatory/lib/src/elements/vm_view.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.
 
 library vm_view_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/src/elements/helpers/nav_bar.dart';
@@ skipping 193 matching lines @@
                     ..title = '${_vm.heapAllocatedMemoryUsage} bytes'
                 ],
               new DivElement()
                 ..classes = ['memberItem']
                 ..children = [
                   new DivElement()
                     ..classes = ['memberName']
                     ..text = 'native heap allocation count',
                   new DivElement()
                     ..classes = ['memberValue']
-                    ..text = _vm.heapAllocationCount
+                    ..text = '${_vm.heapAllocationCount}'
                 ],
  
               new BRElement(),
               new DivElement()
                 ..classes = ['memberItem']
                 ..children = [
                   new DivElement()
                     ..classes = ['memberName']
                     ..children = [
                       new SpanElement()..text = 'see ',
@@ skipping 23 matching lines @@
                               queue: _r.queue)
                         ],
                       new HRElement()
                     ])
                 .toList(),
           new ViewFooterElement(queue: _r.queue)
         ]
     ];
   }
 }