Refactor service tests in preparation of running on sky_shell

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:async';
 import 'dart:html';
 import 'observatory_element.dart';
 import 'package:charted/charted.dart';
@@ skipping 138 matching lines @@
       if (refreshAutoQueued) {
         refreshAuto();
       }
     }).catchError(app.handleException);
   }
 
   static const _USED_INDEX = 0;
   static const _FREE_INDEX = 1;
   static const _EXTERNAL_INDEX = 2;
 
-  static const _LABEL_INDEX = 0;
   static const _VALUE_INDEX = 1;
 
   void _initPieChartData(List rows) {
     rows.add(['Used', 0]);
     rows.add(['Free', 0]);
     rows.add(['External', 0]);
   }
 
   void _updatePieChartData(List rows, HeapSpace space) {
     rows[_USED_INDEX][_VALUE_INDEX] = space.used;
@@ skipping 227 matching lines @@
   }
 
   @observable String formattedTotalCollectionTime(bool newSpace) {
     if (profile == null) {
       return '';
     }
     var heap = newSpace ? isolate.newSpace : isolate.oldSpace;
     return '${Utils.formatSeconds(heap.totalCollectionTimeInSeconds)} secs';
   }
 }