Revert "Added isolate + thread high watermark tracking to Observatory"

runtime/observatory/lib/src/service/object.dart

Index: runtime/observatory/lib/src/service/object.dart
diff --git a/runtime/observatory/lib/src/service/object.dart b/runtime/observatory/lib/src/service/object.dart
index b905523b82c6be0efa33ce2c916ab7f48ff7ab3f..dc9fb8c6644f1a293a06e59ea97236423df4fc0b 100644
--- a/runtime/observatory/lib/src/service/object.dart
+++ b/runtime/observatory/lib/src/service/object.dart
@@ -1507,9 +1507,6 @@ class Isolate extends ServiceObjectOwner implements M.Isolate {
   List<Thread> get threads => _threads;
   final List<Thread> _threads = new List<Thread>();
 
-  int get memoryHighWatermark => _memoryHighWatermark;
-  int _memoryHighWatermark;
-
   int get numZoneHandles => _numZoneHandles;
   int _numZoneHandles;
 
@@ -1641,11 +1638,10 @@ class Isolate extends ServiceObjectOwner implements M.Isolate {
     }
 
     threads.clear();
-    if(map['_threads'] != null) {
-      threads.addAll(map['_threads']);
+    if(map['threads'] != null) {
+      threads.addAll(map['threads']);
     }
 
-    _memoryHighWatermark = int.parse(map['_memoryHighWatermark']);
     if (map['threads'] != null) {
       threads.addAll(map['threads']);
     }
@@ -3089,8 +3085,6 @@ class Thread extends ServiceObject implements M.Thread {
   M.ThreadKind _kind;
   String get kindString => _kindString;
   String _kindString;
-  int get memoryHighWatermark => _memoryHighWatermark;
-  int _memoryHighWatermark;
   List<Zone> get zones => _zones;
   final List<Zone> _zones = new List<Zone>();
 
@@ -3128,9 +3122,6 @@ class Thread extends ServiceObject implements M.Thread {
       default:
         assert(false);
     }
-
-    _memoryHighWatermark = int.parse(map['_memoryHighWatermark']);
-
     zones.clear();
     zoneList.forEach((zone) {
       int capacity = zone['capacity'];