Added methods to surface number of zone and scoped handles for each isolate.

runtime/observatory/lib/src/elements/isolate_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 isolate_view_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/src/elements/curly_block.dart';
@@ skipping 251 matching lines @@
                     ..text = 'service protocol extensions',
                   new DivElement()
                     ..classes = ['memberValue']
                     ..text = '${_isolate.extensionRPCs}'
                 ],
               new DivElement()
                 ..classes = ['memberItem']
                 ..children = [
                   new DivElement()
                     ..classes = ['memberName']
+                    ..text = 'zone handles',

[Cutch, 2017/01/03 18:16:49]

How about something more like:

"Allocated zone handle count"

(here and below)

[bkonyi, 2017/01/03 20:00:10]

Done.

+                  new DivElement()
+                    ..classes = ['memberValue']
+                    ..text = '${_isolate.numZoneHandles}'
+                ],
+              new DivElement()
+                ..classes = ['memberItem']
+                ..children = [
+                  new DivElement()
+                    ..classes = ['memberName']
+                    ..text = 'scoped handles',
+                  new DivElement()
+                    ..classes = ['memberValue']
+                    ..text = '${_isolate.numScopedHandles}'
+                ],
+              new DivElement()
+                ..classes = ['memberItem']
+                ..children = [
+                  new DivElement()
+                    ..classes = ['memberName']
                     ..text = 'object store',
                   new DivElement()
                     ..classes = ['memberValue']
                     ..children = [
                       new AnchorElement(href: Uris.objectStore(_isolate))
                         ..text = 'object store'
                     ]
                 ],
               new BRElement(),
               new DivElement()
@@ skipping 117 matching lines @@
       _function = await _functions.get(_isolate, frame.function.id);
     }
     if (_isolate.rootLibrary != null) {
       final rootLibrary =
           await _libraries.get(_isolate, _isolate.rootLibrary.id);
       _rootScript = rootLibrary.rootScript;
     }
     _r.dirty();
   }
 }