Fix auto-refresh in Heap profile.

runtime/observatory/lib/src/elements/heap_profile.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 heap_profile_element;
 
 import 'dart:html';
 import 'observatory_element.dart';
+import 'package:logging/logging.dart';
 import 'package:observatory/app.dart';
 import 'package:observatory/service.dart';
 import 'package:observatory/elements.dart';
 import 'package:polymer/polymer.dart';
 
 class ClassSortedTable extends SortedTable {
 
   ClassSortedTable(columns) : super(columns);
 
   @override
@@ skipping 76 matching lines @@
     _classTableBody = shadowRoot.querySelector('#classTableBody');
     _subscription = app.vm.events.stream.where(
         (event) => event.isolate == isolate).listen(_onEvent);
   }
 
   @override
   void detached() {
     _subscription.cancel((){});
     super.detached();
   }
-
+  
+  // Keep at most one outstanding auto-refresh RPC.
+  bool refreshAutoPending = false;
+  bool refreshAutoQueued = false;
+  
   void _onEvent(ServiceEvent event) {
     if (autoRefresh && event.eventType == 'GC') {
-      refresh((){});
+      if (!refreshAutoPending) {
+        refreshAuto();
+      } else {
+        // Remember to refresh once more, to ensure latest profile.
+        refreshAutoQueued = true;
+      }
     }
   }
 
+  void refreshAuto() {
+    refreshAutoPending = true;
+    refreshAutoQueued = false;
+    refresh(() {
+      refreshAutoPending = false;
+      // Keep refreshing if at least one GC event was received while waiting.
+      if (refreshAutoQueued) {
+        refreshAuto();
+      }
+    });
+  }
+
   void _updatePieCharts() {
     assert(profile != null);
     _newPieDataTable.clearRows();
     _newPieDataTable.addRow(['Used', isolate.newSpace.used]);
     _newPieDataTable.addRow(['Free',
         isolate.newSpace.capacity - isolate.newSpace.used]);
     _newPieDataTable.addRow(['External', isolate.newSpace.external]);
     _oldPieDataTable.clearRows();
     _oldPieDataTable.addRow(['Used', isolate.oldSpace.used]);
     _oldPieDataTable.addRow(['Free',
@@ skipping 215 matching lines @@
   }
 
   @observable String formattedTotalCollectionTime(bool newSpace) {
     if (profile == null) {
       return '';
     }
     var heap = newSpace ? isolate.newSpace : isolate.oldSpace;
     return '${Utils.formatSeconds(heap.totalCollectionTimeInSeconds)} secs';
   }
 }