Moved isolate high watermark calculations into the Observatory client.

runtime/observatory/lib/src/service/object.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.
 
 part of service;
 
 // Some value smaller than the object ring, so requesting a large array
 // doesn't result in an expired ref because the elements lapped it in the
 // object ring.
 const int kDefaultFieldLimit = 100;
@@ skipping 1490 matching lines @@
 
   DartError error;
   StreamController _snapshotFetch;
 
   List<ByteData> _chunksInProgress;
 
   List<Thread> get threads => _threads;
   final List<Thread> _threads = new List<Thread>();
 
   int get memoryHighWatermark => _memoryHighWatermark;
-  int _memoryHighWatermark;
+  int _memoryHighWatermark = 0;
 
   int get numZoneHandles => _numZoneHandles;
   int _numZoneHandles;
 
   int get numScopedHandles => _numScopedHandles;
   int _numScopedHandles;
 
   void _loadHeapSnapshot(ServiceEvent event) {
     if (_snapshotFetch == null || _snapshotFetch.isClosed) {
       // No outstanding snapshot request. Presumably another client asked for a
@@ skipping 116 matching lines @@
     extensionRPCs.clear();
     if (map['extensionRPCs'] != null) {
       extensionRPCs.addAll(map['extensionRPCs']);
     }
 
     threads.clear();
     if(map['_threads'] != null) {
       threads.addAll(map['_threads']);
     }
 
-    _memoryHighWatermark = int.parse(map['_memoryHighWatermark']);
+    int currentMemoryHighWatermark = 0;
+    for (var i = 0; i < threads.length; i++) {
+      currentMemoryHighWatermark += threads[i].memoryHighWatermark;
+    }
 
-    if (map['threads'] != null) {
-      threads.addAll(map['threads']);
+    if (currentMemoryHighWatermark > _memoryHighWatermark) {
+      _memoryHighWatermark = currentMemoryHighWatermark;
     }
 
     _numZoneHandles = map['_numZoneHandles'];
     _numScopedHandles = map['_numScopedHandles'];
   }
 
   Future<TagProfile> updateTagProfile() {
     return isolate.invokeRpcNoUpgrade('_getTagProfile', {}).then((Map map) {
       var seconds = new DateTime.now().millisecondsSinceEpoch / 1000.0;
       tagProfile._processTagProfile(seconds, map);
@@ skipping 2852 matching lines @@
     var v = list[i];
     if ((v is Map) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is List) {
       _upgradeList(v, owner);
     } else if (v is Map) {
       _upgradeMap(v, owner);
     }
   }
 }