Add Function based profile tree

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:observatory/app.dart';
 import 'package:observatory/service.dart';
@@ skipping 84 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();
   }
-  
+
   void _onEvent(ServiceEvent event) {
     if (autoRefresh && event.eventType == 'GC') {
       refresh((){});
     }
   }
-  
+
   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';
   }
 }