Add current rss and embedder name to Observatory

runtime/observatory/tests/service/vm_test.dart

 // Copyright (c) 2015, 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.
 // VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 
 var tests = [
   (Isolate isolate) {
     VM vm = isolate.owner;
     expect(vm.targetCPU, isNotNull);
     expect(vm.architectureBits == 32 || vm.architectureBits == 64, isTrue);
+    expect(vm.embedder, equals("Dart VM"));
+    expect(vm.currentRSS, isNotNull);
+    expect(vm.currentRSS, greaterThan(0));
+    expect(vm.maxRSS, isNotNull);
+    expect(vm.maxRSS, greaterThan(0));
   },
 ];
 
 main(args) => runIsolateTests(args, tests);