[observatory] Default sort allocation profiles by size instead of name.

runtime/observatory/lib/src/elements/allocation_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.
 
 import 'dart:async';
 import 'dart:html';
 import 'package:charted/charted.dart';
 import "package:charted/charts/charts.dart";
 import 'package:observatory/models.dart' as M;
 import 'package:observatory/src/elements/class_ref.dart';
@@ skipping 46 matching lines @@
 
   M.VM _vm;
   M.IsolateRef _isolate;
   M.EventRepository _events;
   M.NotificationRepository _notifications;
   M.AllocationProfileRepository _repository;
   M.AllocationProfile _profile;
   bool _autoRefresh = false;
   bool _isCompacted = false;
   StreamSubscription _gcSubscription;
-  _SortingField _sortingField = _SortingField.className;
-  _SortingDirection _sortingDirection = _SortingDirection.ascending;
+  _SortingField _sortingField = _SortingField.currentSize;
+  _SortingDirection _sortingDirection = _SortingDirection.descending;
 
   M.VMRef get vm => _vm;
   M.IsolateRef get isolate => _isolate;
   M.NotificationRepository get notifications => _notifications;
 
   factory AllocationProfileElement(
       M.VM vm,
       M.IsolateRef isolate,
       M.EventRepository events,
       M.NotificationRepository notifications,
@@ skipping 558 matching lines @@
   static int _getNewCurrentInstances(M.ClassHeapStats s) =>
       s.newSpace.current.instances;
   static int _getOldAccumulatedSize(M.ClassHeapStats s) =>
       s.oldSpace.accumulated.bytes;
   static int _getOldAccumulatedInstances(M.ClassHeapStats s) =>
       s.oldSpace.accumulated.instances;
   static int _getOldCurrentSize(M.ClassHeapStats s) => s.oldSpace.current.bytes;
   static int _getOldCurrentInstances(M.ClassHeapStats s) =>
       s.oldSpace.current.instances;
 }