Add callers and callees to profiler output

runtime/bin/vmservice/client/lib/src/observatory_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:async';
 import 'dart:html';
 import 'package:logging/logging.dart';
 import 'package:polymer/polymer.dart';
 import 'observatory_element.dart';
 
 /// Displays an Error response.
 @CustomTag('heap-profile')
 class HeapProfileElement extends ObservatoryElement {
   // Indexes into VM provided map.
   static const ALLOCATED_BEFORE_GC = 0;
@@ skipping 108 matching lines @@
         return v['new'][LIVE_AFTER_GC_SIZE];
       case 5:
         return v['old'][LIVE_AFTER_GC_SIZE] + v['old'][ALLOCATED_SINCE_GC_SIZE];
       case 6:
         return v['old'][ALLOCATED_SINCE_GC_SIZE];
       case 7:
         return v['old'][ALLOCATED_BEFORE_GC_SIZE];
       case 8:
         return v['old'][LIVE_AFTER_GC_SIZE];
     }
+    return null;
   }
 
   void refreshData(Event e, var detail, Node target) {
     var isolateId = app.locationManager.currentIsolateId();
     var isolate = app.isolateManager.getIsolate(isolateId);
     if (isolate == null) {
       Logger.root.info('No isolate found.');
       return;
     }
     var request = '/$isolateId/allocationprofile';
@@ skipping 34 matching lines @@
 
   @observable String formattedTotalCollectionTime(bool newSpace) {
     if (profile == null) {
       return '';
     }
     String space = newSpace ? 'new' : 'old';
     Map heap = profile['heaps'][space];
     return '${ObservatoryApplication.timeUnits(heap['time'])} secs';
   }
 }