Make retained size human-readable.

runtime/bin/vmservice/client/lib/src/elements/instance_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 instance_view_element;
 
 import 'dart:async';
 import 'observatory_element.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
 @CustomTag('instance-view')
 class InstanceViewElement extends ObservatoryElement {
   @published ServiceMap instance;
   @published ServiceMap path;
+  @observable int retainedBytes = null;
 
   InstanceViewElement.created() : super.created();
 
   Future<ServiceObject> eval(String text) {
     return instance.isolate.get(
         instance.id + "/eval?expr=${Uri.encodeComponent(text)}");
   }
 
   // TODO(koda): Add no-arg "calculate-link" instead of reusing "eval-link".
   Future<ServiceObject> retainedSize(var dummy) {
-    return instance.isolate.get(instance.id + "/retained");
+    return instance.isolate.get(instance.id + "/retained")
+        .then((ServiceMap obj) {
+          retainedBytes = int.parse(obj['valueAsString']);
+        });
   }
 
   Future<ServiceObject> retainingPath(var arg) {
     return instance.isolate.get(instance.id + "/retaining_path?limit=$arg")
         .then((ServiceObject obj) {
           path = obj;
         });
   }
 
   void refresh(var done) {
     instance.reload().whenComplete(done);
   }
 }