Provide a logical view of VM-internal maps in Observatory.

runtime/observatory/tests/service/get_object_rpc_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=--compile-all --error_on_bad_type --error_on_bad_override
 
 library get_object_rpc_test;
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 88 matching lines @@
     expect(result['class']['name'], equals('_GrowableList'));
     expect(result['size'], isPositive);
     expect(result['fields'], isEmpty);
     expect(result['elements'].length, equals(3));
     expect(result['elements'][0]['index'], equals(0));
     expect(result['elements'][0]['value']['type'], equals('@Instance'));
     expect(result['elements'][0]['value']['kind'], equals('Int'));
     expect(result['elements'][0]['value']['valueAsString'], equals('3'));
   },
 
+  // A built-in Map.
+  (Isolate isolate) async {
+    // Call eval to get a Dart map.
+    var evalResult = await eval(isolate, '{"x": 3, "y": 4}');
+    var params = {
+      'objectId': evalResult['id'],
+    };
+    var result = await isolate.invokeRpcNoUpgrade('getObject', params);
+    expect(result['type'], equals('Instance'));
+    expect(result['kind'], equals('Map'));
+    expect(result['_vmType'], equals('LinkedHashMap'));
+    expect(result['id'], startsWith('objects/'));
+    expect(result['valueAsString'], isNull);
+    expect(result['class']['type'], equals('@Class'));
+    expect(result['class']['name'], equals('_InternalLinkedHashMap'));
+    expect(result['size'], isPositive);
+    expect(result['fields'], isEmpty);
+    expect(result['associations'].length, equals(2));
+    expect(result['associations'][0]['key']['type'], equals('@Instance'));
+    expect(result['associations'][0]['key']['kind'], equals('String'));
+    expect(result['associations'][0]['key']['valueAsString'], equals('x'));
+    expect(result['associations'][0]['value']['type'], equals('@Instance'));
+    expect(result['associations'][0]['value']['kind'], equals('Int'));
+    expect(result['associations'][0]['value']['valueAsString'], equals('3'));
+    expect(result['associations'][1]['key']['type'], equals('@Instance'));
+    expect(result['associations'][1]['key']['kind'], equals('String'));
+    expect(result['associations'][1]['key']['valueAsString'], equals('y'));
+    expect(result['associations'][1]['value']['type'], equals('@Instance'));
+    expect(result['associations'][1]['value']['kind'], equals('Int'));
+    expect(result['associations'][1]['value']['valueAsString'], equals('4'));
+  },
+
   // An expired object.
   (Isolate isolate) async {
     var params = {
       'objectId': 'objects/99999999',
     };
     var result = await isolate.invokeRpcNoUpgrade('getObject', params);
     expect(result['type'], equals('Sentinel'));
     expect(result['kind'], startsWith('Expired'));
     expect(result['valueAsString'], equals('<expired>'));
     expect(result['class'], isNull);
@@ skipping 303 matching lines @@
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kInvalidParams));
       expect(e.message,
              "getObject: invalid 'objectId' parameter: code/0");
     }
     expect(caughtException, isTrue);
   },
 ];
 
 main(args) async => runIsolateTests(args, tests, testeeBefore:warmup);