Add current rss and embedder name to Observatory

runtime/observatory/lib/src/models/objects/vm.dart

 // Copyright (c) 2016, 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 models;
 
 abstract class VMRef {
   /// A name identifying this vm. Not guaranteed to be unique.
   String get name;
 
@@ skipping 12 matching lines @@
 
   /// The CPU we are generating code for.
   String get targetCPU;
 
   /// The CPU we are actually running on.
   String get hostCPU;
 
   /// The Dart VM version string.
   String get version;
 
+  String get embedder;
+
   /// The amount of memory currently allocated by native code in zones.
   int get nativeZoneMemoryUsage;
 
   /// The process id for the VM.
   int get pid;
 
   /// The current amount of native heap allocated memory within the VM.
   int get heapAllocatedMemoryUsage;
 
   /// The current number of allocations on the native heap within the VM.
   int get heapAllocationCount;
 
   int get maxRSS;
+  int get currentRSS;
 
   /// The time that the VM started in milliseconds since the epoch.
   ///
   /// Suitable to pass to DateTime.fromMillisecondsSinceEpoch.
   DateTime get startTime;
 
   // A list of isolates running in the VM.
   Iterable<IsolateRef> get isolates;
 }