diff --git a/DEPS b/DEPS
index 1f170d29455..3b96c940a07 100644
--- a/DEPS
+++ b/DEPS
@@ -146,7 +146,7 @@ vars = {
   "usage_tag": "3.4.0",
   "watcher_rev": "0.9.7+14",
   "web_components_rev": "8f57dac273412a7172c8ade6f361b407e2e4ed02",
-  "web_socket_channel_tag": "1.0.15",
+  "web_socket_channel_tag": "1.1.0",
   "WebCore_rev": "fb11e887f77919450e497344da570d780e078bc8",
   "yaml_tag": "2.2.0",
   "zlib_rev": "c44fb7248079cc3d5563b14b3f758aee60d6b415",
diff --git a/pkg/dds/lib/dds.dart b/pkg/dds/lib/dds.dart
index d2bb5eae518..03ced9ff837 100644
--- a/pkg/dds/lib/dds.dart
+++ b/pkg/dds/lib/dds.dart
@@ -7,15 +7,24 @@
 library dds;
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
+import 'dart:typed_data';
 
+import 'package:async/async.dart';
+import 'package:json_rpc_2/json_rpc_2.dart' as json_rpc;
+import 'package:pedantic/pedantic.dart';
 import 'package:shelf/shelf.dart';
 import 'package:shelf/shelf_io.dart' as io;
 import 'package:shelf_proxy/shelf_proxy.dart';
 import 'package:shelf_web_socket/shelf_web_socket.dart';
+import 'package:stream_channel/stream_channel.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
 
+part 'src/binary_compatible_peer.dart';
+part 'src/client.dart';
 part 'src/dds_impl.dart';
+part 'src/stream_manager.dart';
 
 /// An intermediary between a Dart VM service and its clients that offers
 /// additional functionality on top of the standard VM service protocol.
diff --git a/pkg/dds/lib/src/binary_compatible_peer.dart b/pkg/dds/lib/src/binary_compatible_peer.dart
new file mode 100644
index 00000000000..7c5b83b69fb
--- /dev/null
+++ b/pkg/dds/lib/src/binary_compatible_peer.dart
@@ -0,0 +1,60 @@
+// Copyright (c) 2020, 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 dds;
+
+/// Adds support for binary events send from the VM service, which are not part
+/// of the official JSON RPC 2.0 specification.
+///
+/// A binary event from the VM service has the form:
+/// ```
+/// type BinaryEvent {
+///  dataOffset : uint32,
+///  metadata : uint8[dataOffset-4],
+///  data : uint8[],
+/// }
+/// ```
+/// where `metadata` is the JSON body of the event.
+///
+/// [_BinaryCompatiblePeer] assumes that only stream events can contain a
+/// binary payload (e.g., clients cannot send a `BinaryEvent` to the VM service).
+class _BinaryCompatiblePeer extends json_rpc.Peer {
+  _BinaryCompatiblePeer(WebSocketChannel ws, _StreamManager streamManager)
+      : super(
+          ws.transform<String>(
+            StreamChannelTransformer(
+              StreamTransformer<dynamic, String>.fromHandlers(
+                  handleData: (data, EventSink<String> sink) =>
+                      _transformStream(streamManager, data, sink)),
+              StreamSinkTransformer<String, dynamic>.fromHandlers(
+                handleData: (String data, EventSink<dynamic> sink) {
+                  sink.add(data);
+                },
+              ),
+            ),
+          ),
+        );
+
+  static void _transformStream(
+      _StreamManager streamManager, dynamic data, EventSink<String> sink) {
+    if (data is String) {
+      // Non-binary messages come in as Strings. Simply forward to the sink.
+      sink.add(data);
+    } else if (data is Uint8List) {
+      // Only binary events will result in `data` being of type Uint8List. We
+      // need to manually forward them here.
+      final bytesView =
+          ByteData.view(data.buffer, data.offsetInBytes, data.lengthInBytes);
+      const metadataOffset = 4;
+      final dataOffset = bytesView.getUint32(0, Endian.little);
+      final metadataLength = dataOffset - metadataOffset;
+      final metadata = Utf8Decoder().convert(new Uint8List.view(
+          bytesView.buffer,
+          bytesView.offsetInBytes + metadataOffset,
+          metadataLength));
+      final decodedMetadata = json.decode(metadata);
+      streamManager.streamNotify(decodedMetadata['params']['streamId'], data);
+    }
+  }
+}
diff --git a/pkg/dds/lib/src/client.dart b/pkg/dds/lib/src/client.dart
new file mode 100644
index 00000000000..11dac829dc4
--- /dev/null
+++ b/pkg/dds/lib/src/client.dart
@@ -0,0 +1,68 @@
+// Copyright (c) 2020, 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 dds;
+
+/// Representation of a single DDS client which manages the connection and
+/// DDS request intercepting / forwarding.
+class _DartDevelopmentServiceClient {
+  _DartDevelopmentServiceClient(
+    this.dds,
+    this.ws,
+    json_rpc.Peer vmServicePeer,
+  ) : _vmServicePeer = vmServicePeer {
+    _clientPeer = json_rpc.Peer(ws.cast<String>());
+    _registerJsonRpcMethods();
+  }
+
+  /// Start receiving JSON RPC requests from the client.
+  ///
+  /// Returned future completes when the peer is closed.
+  Future<void> listen() => _clientPeer.listen().then(
+        (_) => dds.streamManager.clientDisconnect(this),
+      );
+
+  /// Close the connection to the client.
+  Future<void> close() async {
+    // Cleanup the JSON RPC server for this connection if DDS has shutdown.
+    await _clientPeer.close();
+  }
+
+  /// Send a JSON RPC notification to the client.
+  void sendNotification(String method, [dynamic parameters]) async {
+    if (_clientPeer.isClosed) {
+      return;
+    }
+    _clientPeer.sendNotification(method, parameters);
+  }
+
+  /// Registers handlers for JSON RPC methods which need to be intercepted by
+  /// DDS as well as fallback request forwarder.
+  void _registerJsonRpcMethods() {
+    _clientPeer.registerMethod('streamListen', (parameters) async {
+      final streamId = parameters['streamId'].asString;
+      await dds.streamManager.streamListen(this, streamId);
+      return _success;
+    });
+
+    _clientPeer.registerMethod('streamCancel', (parameters) async {
+      final streamId = parameters['streamId'].asString;
+      await dds.streamManager.streamCancel(this, streamId);
+      return _success;
+    });
+
+    // Unless otherwise specified, the request is forwarded to the VM service.
+    _clientPeer.registerFallback((parameters) async =>
+        await _vmServicePeer.sendRequest(parameters.method, parameters.asMap));
+  }
+
+  static const _success = <String, dynamic>{
+    'type': 'Success',
+  };
+
+  final _DartDevelopmentService dds;
+  final json_rpc.Peer _vmServicePeer;
+  final WebSocketChannel ws;
+  json_rpc.Peer _clientPeer;
+}
diff --git a/pkg/dds/lib/src/dds_impl.dart b/pkg/dds/lib/src/dds_impl.dart
index 37f019adc6f..fb2bf749950 100644
--- a/pkg/dds/lib/src/dds_impl.dart
+++ b/pkg/dds/lib/src/dds_impl.dart
@@ -5,12 +5,20 @@
 part of dds;
 
 class _DartDevelopmentService implements DartDevelopmentService {
-  _DartDevelopmentService(this._remoteVmServiceUri, this._uri);
+  _DartDevelopmentService(this._remoteVmServiceUri, this._uri) {
+    _streamManager = _StreamManager(this);
+  }
 
   Future<void> startService() async {
     // Establish the connection to the VM service.
-    _vmServiceSocket = await WebSocket.connect(remoteVmServiceWsUri.toString());
-    _vmServiceStream = _vmServiceSocket.asBroadcastStream();
+    _vmServiceSocket = WebSocketChannel.connect(remoteVmServiceWsUri);
+    _vmServiceClient = _BinaryCompatiblePeer(_vmServiceSocket, _streamManager);
+    // Setup the JSON RPC client with the VM service.
+    unawaited(_vmServiceClient.listen());
+
+    // Setup stream event handling.
+    streamManager.listen();
+
     // Once we have a connection to the VM service, we're ready to spawn the intermediary.
     await _startDDSServer();
   }
@@ -28,8 +36,20 @@ class _DartDevelopmentService implements DartDevelopmentService {
 
   /// Stop accepting requests after gracefully handling existing requests.
   Future<void> shutdown() async {
+    // Don't accept anymore HTTP requests.
     await _server.close();
-    await _vmServiceSocket.close();
+
+    // Close all incoming websocket connections.
+    final futures = <Future>[];
+    for (final client in _clients) {
+      futures.add(client.close());
+    }
+    await Future.wait(futures);
+
+    // Close connection to VM service.
+    await _vmServiceSocket.sink.close();
+
+    _done.complete();
   }
 
   // Attempt to upgrade HTTP requests to a websocket before processing them as
@@ -38,16 +58,18 @@ class _DartDevelopmentService implements DartDevelopmentService {
   Cascade _handlers() => Cascade().add(_webSocketHandler()).add(_httpHandler());
 
   Handler _webSocketHandler() => webSocketHandler((WebSocketChannel ws) {
-        // TODO(bkonyi): actually process requests instead of blindly forwarding them.
-        _vmServiceStream.listen(
-          (event) => ws.sink.add(event),
-          onDone: () => ws.sink.close(),
+        final client = _DartDevelopmentServiceClient(
+          this,
+          ws,
+          _vmServiceClient,
         );
-        ws.stream.listen((event) => _vmServiceSocket.add(event));
+        _clients.add(client);
+        client.listen().then((_) => _clients.remove(client));
       });
 
   Handler _httpHandler() {
-    // TODO(bkonyi): actually process requests instead of blindly forwarding them.
+    // DDS doesn't support any HTTP requests itself, so we just forward all of
+    // them to the VM service.
     final cascade = Cascade().add(proxyHandler(remoteVmServiceUri));
     return cascade.handler;
   }
@@ -79,7 +101,15 @@ class _DartDevelopmentService implements DartDevelopmentService {
 
   bool get isRunning => _uri != null;
 
-  WebSocket _vmServiceSocket;
-  Stream _vmServiceStream;
+  Future<void> get done => _done.future;
+  Completer _done = Completer<void>();
+
+  _StreamManager get streamManager => _streamManager;
+  _StreamManager _streamManager;
+
+  final List<_DartDevelopmentServiceClient> _clients = [];
+
+  json_rpc.Peer _vmServiceClient;
+  WebSocketChannel _vmServiceSocket;
   HttpServer _server;
 }
diff --git a/pkg/dds/lib/src/stream_manager.dart b/pkg/dds/lib/src/stream_manager.dart
new file mode 100644
index 00000000000..318cc39a78b
--- /dev/null
+++ b/pkg/dds/lib/src/stream_manager.dart
@@ -0,0 +1,113 @@
+// Copyright (c) 2020, 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 dds;
+
+class _StreamManager {
+  _StreamManager(this.dds);
+
+  /// Send `streamNotify` notifications to clients subscribed to `streamId`.
+  ///
+  /// If `data` is of type `Uint8List`, the notification is assumed to be a
+  /// binary event and is forwarded directly over the subscriber's websocket.
+  /// Otherwise, the event is sent via the JSON RPC client.
+  void streamNotify(String streamId, data) {
+    if (streamListeners.containsKey(streamId)) {
+      final listeners = streamListeners[streamId];
+      final isBinaryData = data is Uint8List;
+      for (final listener in listeners) {
+        if (isBinaryData) {
+          listener.ws.sink.add(data);
+        } else {
+          listener.sendNotification('streamNotify', data);
+        }
+      }
+    }
+  }
+
+  /// Start listening for `streamNotify` events from the VM service and forward
+  /// them to the clients which have subscribed to the stream.
+  void listen() => dds._vmServiceClient.registerMethod(
+        'streamNotify',
+        (parameters) {
+          final streamId = parameters['streamId'].asString;
+          streamNotify(streamId, parameters.value);
+        },
+      );
+
+  /// Subscribes `client` to a stream.
+  ///
+  /// If `client` is the first client to listen to `stream`, DDS will send a
+  /// `streamListen` request for `stream` to the VM service.
+  Future<void> streamListen(
+    _DartDevelopmentServiceClient client,
+    String stream,
+  ) async {
+    assert(stream != null && stream.isNotEmpty);
+    if (!streamListeners.containsKey(stream)) {
+      // This will return an RPC exception if the stream doesn't exist. This
+      // will throw and the exception will be forwarded to the client.
+      final result = await dds._vmServiceClient.sendRequest('streamListen', {
+        'streamId': stream,
+      });
+      assert(result['type'] == 'Success');
+      streamListeners[stream] = <_DartDevelopmentServiceClient>[];
+    }
+    if (streamListeners[stream].contains(client)) {
+      throw kStreamAlreadySubscribedException;
+    }
+    streamListeners[stream].add(client);
+  }
+
+  /// Unsubscribes `client` from a stream.
+  ///
+  /// If `client` is the last client to unsubscribe from `stream`, DDS will
+  /// send a `streamCancel` request for `stream` to the VM service.
+  Future<void> streamCancel(
+    _DartDevelopmentServiceClient client,
+    String stream,
+  ) async {
+    assert(stream != null && stream.isNotEmpty);
+    final listeners = streamListeners[stream];
+    if (listeners == null || !listeners.contains(client)) {
+      throw kStreamNotSubscribedException;
+    }
+    listeners.remove(client);
+    if (listeners.isEmpty) {
+      streamListeners.remove(stream);
+      final result = await dds._vmServiceClient.sendRequest('streamCancel', {
+        'streamId': stream,
+      });
+      assert(result['type'] == 'Success');
+    } else {
+      streamListeners[stream] = listeners;
+    }
+  }
+
+  /// Cleanup stream subscriptions for `client` when it has disconnected.
+  void clientDisconnect(_DartDevelopmentServiceClient client) {
+    for (final streamId in streamListeners.keys.toList()) {
+      streamCancel(client, streamId);
+    }
+  }
+
+  // These error codes must be kept in sync with those in vm/json_stream.h and
+  // vmservice.dart.
+  static const kStreamAlreadySubscribed = 103;
+  static const kStreamNotSubscribed = 104;
+
+  // Keep these messages in sync with the VM service.
+  static final kStreamAlreadySubscribedException = json_rpc.RpcException(
+    kStreamAlreadySubscribed,
+    'Stream already subscribed',
+  );
+
+  static final kStreamNotSubscribedException = json_rpc.RpcException(
+    kStreamNotSubscribed,
+    'Stream not subscribed',
+  );
+
+  final _DartDevelopmentService dds;
+  final streamListeners = <String, List<_DartDevelopmentServiceClient>>{};
+}
diff --git a/pkg/dds/pubspec.yaml b/pkg/dds/pubspec.yaml
index 8734df5f3cd..9dbb70e8219 100644
--- a/pkg/dds/pubspec.yaml
+++ b/pkg/dds/pubspec.yaml
@@ -11,13 +11,15 @@ environment:
   sdk: '>=2.6.0 <3.0.0'
 
 dependencies:
+  async: ^2.4.1
   json_rpc_2: ^2.1.0
+  pedantic: ^1.7.0
   shelf: ^0.7.5
   shelf_proxy: ^0.1.0+7
   shelf_web_socket: ^0.2.3
+  stream_channel: ^2.0.0
   web_socket_channel: ^1.1.0
 
 dev_dependencies:
-  pedantic: ^1.7.0
   test: ^1.0.0
   vm_service: ^4.0.0
diff --git a/pkg/test_runner/lib/src/test_suite.dart b/pkg/test_runner/lib/src/test_suite.dart
index b0cb187687f..6ac30e0b5c2 100644
--- a/pkg/test_runner/lib/src/test_suite.dart
+++ b/pkg/test_runner/lib/src/test_suite.dart
@@ -583,6 +583,8 @@ class StandardTestSuite extends TestSuite {
       _enqueueStandardTest(testFile, expectationSet, onTest);
     } else if (configuration.runtime.isBrowser) {
       _enqueueBrowserTest(testFile, expectationSet, onTest);
+    } else if (suiteName == 'service') {
+      _enqueueServiceTest(testFile, expectationSet, onTest);
     } else {
       _enqueueStandardTest(testFile, expectationSet, onTest);
     }
@@ -616,6 +618,45 @@ class StandardTestSuite extends TestSuite {
     }
   }
 
+  void _enqueueServiceTest(
+      TestFile testFile, Set<Expectation> expectations, TestCaseEvent onTest) {
+    var commonArguments = _commonArgumentsFromFile(testFile);
+
+    var vmOptionsList = getVmOptions(testFile);
+    assert(!vmOptionsList.isEmpty);
+
+    bool emitDdsTest = false;
+    for (int i = 0; i < 2; ++i) {
+      for (var vmOptionsVariant = 0;
+          vmOptionsVariant < vmOptionsList.length;
+          vmOptionsVariant++) {
+        var vmOptions = vmOptionsList[vmOptionsVariant];
+        var allVmOptions = vmOptions;
+        if (!extraVmOptions.isEmpty) {
+          allVmOptions = vmOptions.toList()..addAll(extraVmOptions);
+        }
+        if (emitDdsTest) {
+          allVmOptions.add('-DUSE_DDS=true');
+        }
+        var isCrashExpected = expectations.contains(Expectation.crash);
+        var commands = _makeCommands(
+            testFile,
+            vmOptionsVariant + (vmOptionsList.length * i),
+            allVmOptions,
+            commonArguments,
+            isCrashExpected);
+        var variantTestName =
+            testFile.name + '/${emitDdsTest ? 'dds' : 'service'}';
+        if (vmOptionsList.length > 1) {
+          variantTestName = "${testFile.name}_$vmOptionsVariant";
+        }
+
+        _addTestCase(testFile, variantTestName, commands, expectations, onTest);
+      }
+      emitDdsTest = true;
+    }
+  }
+
   List<Command> _makeCommands(TestFile testFile, int vmOptionsVariant,
       List<String> vmOptions, List<String> args, bool isCrashExpected) {
     var commands = <Command>[];
diff --git a/pkg/vm_service/CHANGELOG.md b/pkg/vm_service/CHANGELOG.md
index 39645a765a4..292e39387b9 100644
--- a/pkg/vm_service/CHANGELOG.md
+++ b/pkg/vm_service/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+- Fixed issue where RPC format did not conform to the JSON-RPC 2.0
+  specification.
+
 ## 4.0.1
 - Improved documentation.
 - Fixed analysis issues.
diff --git a/pkg/vm_service/lib/src/vm_service.dart b/pkg/vm_service/lib/src/vm_service.dart
index 03d939e28ae..a7660078b2d 100644
--- a/pkg/vm_service/lib/src/vm_service.dart
+++ b/pkg/vm_service/lib/src/vm_service.dart
@@ -1955,13 +1955,17 @@ class VmService implements VmServiceInterface {
 
   Future get onDone => _onDoneCompleter.future;
 
-  Future<T> _call<T>(String method, [Map args]) {
+  Future<T> _call<T>(String method, [Map args = const {}]) {
     String id = '${++_id}';
     Completer<T> completer = Completer<T>();
     _completers[id] = completer;
     _methodCalls[id] = method;
-    Map m = {'id': id, 'method': method};
-    if (args != null) m['params'] = args;
+    Map m = {
+      'jsonrpc': '2.0',
+      'id': id,
+      'method': method,
+      'params': args,
+    };
     String message = jsonEncode(m);
     _onSend.add(message);
     _writeMessage(message);
diff --git a/pkg/vm_service/tool/dart/generate_dart.dart b/pkg/vm_service/tool/dart/generate_dart.dart
index 0e85f27221d..b85bc8cf62a 100644
--- a/pkg/vm_service/tool/dart/generate_dart.dart
+++ b/pkg/vm_service/tool/dart/generate_dart.dart
@@ -118,13 +118,12 @@ final String _implCode = r'''
 
   Future get onDone => _onDoneCompleter.future;
 
-  Future<T> _call<T>(String method, [Map args]) {
+  Future<T> _call<T>(String method, [Map args = const {}]) {
     String id = '${++_id}';
     Completer<T> completer = Completer<T>();
     _completers[id] = completer;
     _methodCalls[id] = method;
-    Map m = {'id': id, 'method': method};
-    if (args != null) m['params'] = args;
+    Map m = {'jsonrpc': '2.0', 'id': id, 'method': method, 'params': args,};
     String message = jsonEncode(m);
     _onSend.add(message);
     _writeMessage(message);
diff --git a/runtime/observatory/lib/service_common.dart b/runtime/observatory/lib/service_common.dart
index 66ff984c047..48181ff55d9 100644
--- a/runtime/observatory/lib/service_common.dart
+++ b/runtime/observatory/lib/service_common.dart
@@ -318,8 +318,12 @@ abstract class CommonWebSocketVM extends VM {
         'params': {'id': serial, 'query': request.method}
       });
     } else {
-      message = json.encode(
-          {'id': serial, 'method': request.method, 'params': request.params});
+      message = json.encode({
+        'jsonrpc': '2.0',
+        'id': serial,
+        'method': request.method,
+        'params': request.params
+      });
     }
     if (request.method != 'getTagProfile' &&
         request.method != 'getIsolateMetric' &&
diff --git a/runtime/observatory/tests/service/break_on_default_constructor_test.dart b/runtime/observatory/tests/service/break_on_default_constructor_test.dart
index bc504c741d2..d968ca21cfa 100644
--- a/runtime/observatory/tests/service/break_on_default_constructor_test.dart
+++ b/runtime/observatory/tests/service/break_on_default_constructor_test.dart
@@ -66,7 +66,7 @@ var tests = <IsolateTest>[
       fail("Expected to find function");
     }
 
-    isolate.resume();
+    await isolate.resume();
   }
 ];
 
diff --git a/runtime/observatory/tests/service/client_name_rpc_test.dart b/runtime/observatory/tests/service/client_name_rpc_test.dart
index 41cbe4fb379..fa204302d19 100644
--- a/runtime/observatory/tests/service/client_name_rpc_test.dart
+++ b/runtime/observatory/tests/service/client_name_rpc_test.dart
@@ -63,4 +63,9 @@ var tests = <VMTest>[
   },
 ];
 
-main(args) async => runVMTests(args, tests);
+main(args) async => runVMTests(
+      args,
+      tests,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/client_resume_approvals_approve_then_disconnect_test.dart b/runtime/observatory/tests/service/client_resume_approvals_approve_then_disconnect_test.dart
index 427706fdfd2..462e3dc414b 100644
--- a/runtime/observatory/tests/service/client_resume_approvals_approve_then_disconnect_test.dart
+++ b/runtime/observatory/tests/service/client_resume_approvals_approve_then_disconnect_test.dart
@@ -60,5 +60,12 @@ final test = <IsolateTest>[
   hasStoppedAtExit,
 ];
 
-Future<void> main(args) => runIsolateTests(args, test,
-    testeeConcurrent: fooBar, pause_on_start: true, pause_on_exit: true);
+Future<void> main(args) => runIsolateTests(
+      args,
+      test,
+      testeeConcurrent: fooBar,
+      pause_on_start: true,
+      pause_on_exit: true,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/client_resume_approvals_disconnect_test.dart b/runtime/observatory/tests/service/client_resume_approvals_disconnect_test.dart
index 9d235224407..50c5d34609f 100644
--- a/runtime/observatory/tests/service/client_resume_approvals_disconnect_test.dart
+++ b/runtime/observatory/tests/service/client_resume_approvals_disconnect_test.dart
@@ -58,5 +58,12 @@ final test = <IsolateTest>[
   hasStoppedAtExit,
 ];
 
-Future<void> main(args) => runIsolateTests(args, test,
-    testeeConcurrent: fooBar, pause_on_start: true, pause_on_exit: true);
+Future<void> main(args) => runIsolateTests(
+      args,
+      test,
+      testeeConcurrent: fooBar,
+      pause_on_start: true,
+      pause_on_exit: true,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/client_resume_approvals_identical_names_test.dart b/runtime/observatory/tests/service/client_resume_approvals_identical_names_test.dart
index d3a09a962d5..27e026c50e5 100644
--- a/runtime/observatory/tests/service/client_resume_approvals_identical_names_test.dart
+++ b/runtime/observatory/tests/service/client_resume_approvals_identical_names_test.dart
@@ -40,5 +40,12 @@ final sameClientNamesTest = <IsolateTest>[
   hasStoppedAtExit,
 ];
 
-Future<void> main(args) => runIsolateTests(args, sameClientNamesTest,
-    testeeConcurrent: fooBar, pause_on_start: true, pause_on_exit: true);
+Future<void> main(args) => runIsolateTests(
+      args,
+      sameClientNamesTest,
+      testeeConcurrent: fooBar,
+      pause_on_start: true,
+      pause_on_exit: true,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/client_resume_approvals_multiple_names_test.dart b/runtime/observatory/tests/service/client_resume_approvals_multiple_names_test.dart
index 5f26a9c9def..e92442c1c7e 100644
--- a/runtime/observatory/tests/service/client_resume_approvals_multiple_names_test.dart
+++ b/runtime/observatory/tests/service/client_resume_approvals_multiple_names_test.dart
@@ -58,5 +58,12 @@ final multipleClientNamesTest = <IsolateTest>[
   },
 ];
 
-Future<void> main(args) => runIsolateTests(args, multipleClientNamesTest,
-    testeeConcurrent: fooBar, pause_on_start: true, pause_on_exit: true);
+Future<void> main(args) => runIsolateTests(
+      args,
+      multipleClientNamesTest,
+      testeeConcurrent: fooBar,
+      pause_on_start: true,
+      pause_on_exit: true,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/client_resume_approvals_name_change_test.dart b/runtime/observatory/tests/service/client_resume_approvals_name_change_test.dart
index 3d33112bc54..b20a5936103 100644
--- a/runtime/observatory/tests/service/client_resume_approvals_name_change_test.dart
+++ b/runtime/observatory/tests/service/client_resume_approvals_name_change_test.dart
@@ -51,5 +51,12 @@ final nameChangeTest = <IsolateTest>[
   hasStoppedAtExit,
 ];
 
-Future<void> main(args) => runIsolateTests(args, nameChangeTest,
-    testeeConcurrent: fooBar, pause_on_start: true, pause_on_exit: true);
+Future<void> main(args) => runIsolateTests(
+      args,
+      nameChangeTest,
+      testeeConcurrent: fooBar,
+      pause_on_start: true,
+      pause_on_exit: true,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/client_resume_approvals_reload_test.dart b/runtime/observatory/tests/service/client_resume_approvals_reload_test.dart
index 250d34978ba..50f7f459411 100644
--- a/runtime/observatory/tests/service/client_resume_approvals_reload_test.dart
+++ b/runtime/observatory/tests/service/client_resume_approvals_reload_test.dart
@@ -60,5 +60,11 @@ final hotReloadTest = <IsolateTest>[
   },
 ];
 
-Future<void> main(args) => runIsolateTests(args, hotReloadTest,
-    testeeConcurrent: fooBar, pause_on_start: true);
+Future<void> main(args) => runIsolateTests(
+      args,
+      hotReloadTest,
+      testeeConcurrent: fooBar,
+      pause_on_start: true,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/enable_service_port_fallback_positive_test.dart b/runtime/observatory/tests/service/enable_service_port_fallback_positive_test.dart
index ca25d5f9f5f..bbac57444e9 100644
--- a/runtime/observatory/tests/service/enable_service_port_fallback_positive_test.dart
+++ b/runtime/observatory/tests/service/enable_service_port_fallback_positive_test.dart
@@ -21,11 +21,15 @@ int selectedPort = 0;
 
 main(args) async {
   selectedPort = await _getUnusedPort();
-  await runVMTests(args, tests,
-      enable_service_port_fallback: true,
-      // Choose a port number that should always be open.
-      port: selectedPort,
-      extraArgs: []);
+  await runVMTests(
+    args, tests,
+    enable_service_port_fallback: true,
+    // Choose a port number that should always be open.
+    port: selectedPort,
+    extraArgs: [],
+    // TODO(bkonyi): investigate failure.
+    enableDds: false,
+  );
 }
 
 Future<int> _getUnusedPort() async {
diff --git a/runtime/observatory/tests/service/external_service_asynchronous_invocation_test.dart b/runtime/observatory/tests/service/external_service_asynchronous_invocation_test.dart
index 277816791cc..58d44deba1e 100644
--- a/runtime/observatory/tests/service/external_service_asynchronous_invocation_test.dart
+++ b/runtime/observatory/tests/service/external_service_asynchronous_invocation_test.dart
@@ -164,4 +164,8 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args, tests,
+      // TODO(bkonyi): service extensions are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/external_service_disappear_test.dart b/runtime/observatory/tests/service/external_service_disappear_test.dart
index eafe5a698d6..a015686b2e3 100644
--- a/runtime/observatory/tests/service/external_service_disappear_test.dart
+++ b/runtime/observatory/tests/service/external_service_disappear_test.dart
@@ -89,4 +89,8 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args, tests,
+      // TODO(bkonyi): service extensions are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/external_service_notification_invocation_test.dart b/runtime/observatory/tests/service/external_service_notification_invocation_test.dart
index 3b1e6953350..a5bfd64fcf3 100644
--- a/runtime/observatory/tests/service/external_service_notification_invocation_test.dart
+++ b/runtime/observatory/tests/service/external_service_notification_invocation_test.dart
@@ -83,4 +83,9 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args,
+      tests,
+      // TODO(bkonyi): service extensions are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/external_service_registration_test.dart b/runtime/observatory/tests/service/external_service_registration_test.dart
index 2ec0d95967d..ce0aea9c7c4 100644
--- a/runtime/observatory/tests/service/external_service_registration_test.dart
+++ b/runtime/observatory/tests/service/external_service_registration_test.dart
@@ -123,4 +123,9 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args,
+      tests,
+      // TODO(bkonyi): service extensions are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/external_service_registration_via_notification_test.dart b/runtime/observatory/tests/service/external_service_registration_via_notification_test.dart
index 333c24e626c..80729ce1839 100644
--- a/runtime/observatory/tests/service/external_service_registration_via_notification_test.dart
+++ b/runtime/observatory/tests/service/external_service_registration_via_notification_test.dart
@@ -103,4 +103,8 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args, tests,
+      // TODO(bkonyi): service extensions are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/external_service_synchronous_invocation_test.dart b/runtime/observatory/tests/service/external_service_synchronous_invocation_test.dart
index 97917b33fed..45c58d82490 100644
--- a/runtime/observatory/tests/service/external_service_synchronous_invocation_test.dart
+++ b/runtime/observatory/tests/service/external_service_synchronous_invocation_test.dart
@@ -126,4 +126,8 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args, tests,
+      // TODO(bkonyi): service extensions are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/get_client_name_rpc_test.dart b/runtime/observatory/tests/service/get_client_name_rpc_test.dart
index d503a91c362..33f2c21ddd7 100644
--- a/runtime/observatory/tests/service/get_client_name_rpc_test.dart
+++ b/runtime/observatory/tests/service/get_client_name_rpc_test.dart
@@ -37,4 +37,10 @@ final test = <IsolateTest>[
   },
 ];
 
-Future<void> main(args) => runIsolateTests(args, test, testeeBefore: fooBar);
+Future<void> main(args) => runIsolateTests(
+      args,
+      test,
+      testeeBefore: fooBar,
+      // TODO(bkonyi): client names are not yet supported in DDS.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/malformed_test.dart b/runtime/observatory/tests/service/malformed_test.dart
index 5fff3fdb13d..9e277c8400b 100644
--- a/runtime/observatory/tests/service/malformed_test.dart
+++ b/runtime/observatory/tests/service/malformed_test.dart
@@ -37,4 +37,11 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests);
+main(args) => runIsolateTests(
+      args,
+      tests,
+      // This test hangs with DDS as package:json_rpc_2 can't parse the JSON
+      // response and is unable to determine the request ID, so the malformed
+      // JSON request will never complete.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/observatory_assets_test.dart b/runtime/observatory/tests/service/observatory_assets_test.dart
index 4b8f8e2044b..a78f448b8e9 100644
--- a/runtime/observatory/tests/service/observatory_assets_test.dart
+++ b/runtime/observatory/tests/service/observatory_assets_test.dart
@@ -22,4 +22,8 @@ var tests = <VMTest>[
   }
 ];
 
-main(args) async => runVMTests(args, tests);
+main(args) async => runVMTests(
+      args, tests,
+      // TODO(bkonyi): DDS doesn't forward Observatory assets properly yet.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/pause_on_start_and_exit_with_child_test.dart b/runtime/observatory/tests/service/pause_on_start_and_exit_with_child_test.dart
index 1d3a8bf7717..cb4b288d61b 100644
--- a/runtime/observatory/tests/service/pause_on_start_and_exit_with_child_test.dart
+++ b/runtime/observatory/tests/service/pause_on_start_and_exit_with_child_test.dart
@@ -101,12 +101,16 @@ var tests = <IsolateTest>[
   },
 ];
 
-main(args) => runIsolateTests(args, tests,
-        testeeConcurrent: testMain,
-        pause_on_start: true,
-        pause_on_exit: true,
-        verbose_vm: true,
-        extraArgs: [
-          '--trace-service',
-          '--trace-service-verbose',
-        ]);
+main(args) => runIsolateTests(
+      args, tests,
+      testeeConcurrent: testMain,
+      pause_on_start: true,
+      pause_on_exit: true,
+      verbose_vm: true,
+      extraArgs: [
+        '--trace-service',
+        '--trace-service-verbose',
+      ],
+      // TODO(bkonyi): investigate failure.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/pause_on_unhandled_async_exceptions2_test.dart b/runtime/observatory/tests/service/pause_on_unhandled_async_exceptions2_test.dart
index 850177a10c2..6f982849d72 100644
--- a/runtime/observatory/tests/service/pause_on_unhandled_async_exceptions2_test.dart
+++ b/runtime/observatory/tests/service/pause_on_unhandled_async_exceptions2_test.dart
@@ -61,7 +61,13 @@ var tests = <IsolateTest>[
   }
 ];
 
-main(args) => runIsolateTests(args, tests,
-    pause_on_unhandled_exceptions: true,
-    testeeConcurrent: testeeMain,
-    extraArgs: extraDebuggingArgs);
+main(args) => runIsolateTests(
+      args,
+      tests,
+      pause_on_unhandled_exceptions: true,
+      testeeConcurrent: testeeMain,
+      extraArgs: extraDebuggingArgs,
+      // TODO(bkonyi): causes ASSERT in debug mode, unrelated to DDS.
+      // See https://github.com/dart-lang/sdk/issues/41379.
+      enableDds: false,
+    );
diff --git a/runtime/observatory/tests/service/service.status b/runtime/observatory/tests/service/service.status
index 20cc72a7b3f..cf5797a57ce 100644
--- a/runtime/observatory/tests/service/service.status
+++ b/runtime/observatory/tests/service/service.status
@@ -29,6 +29,7 @@ get_isolate_after_language_error_test: SkipByDesign
 *: SkipByDesign
 
 [ $system == windows ]
+*: Slow
 async_generator_breakpoint_test: Skip # Issue 29145
 dev_fs_http_put_weird_char_test: Skip # Windows disallows carriage returns in paths
 dev_fs_weird_char_test: Skip # Windows disallows question mark in paths
diff --git a/runtime/observatory/tests/service/stream_subscription_test.dart b/runtime/observatory/tests/service/stream_subscription_test.dart
new file mode 100644
index 00000000000..56f8420c10a
--- /dev/null
+++ b/runtime/observatory/tests/service/stream_subscription_test.dart
@@ -0,0 +1,58 @@
+// Copyright (c) 2020, 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.
+
+import 'package:observatory/service_io.dart';
+import 'package:test/test.dart';
+
+import 'test_helper.dart';
+
+Future streamListen(VM vm, String streamId) async =>
+    await vm.invokeRpcNoUpgrade(
+      'streamListen',
+      {
+        'streamId': streamId,
+      },
+    );
+
+Future streamCancel(VM vm, String streamId) async =>
+    await vm.invokeRpcNoUpgrade(
+      'streamCancel',
+      {
+        'streamId': streamId,
+      },
+    );
+
+var tests = <VMTest>[
+  // Check double subscription fails.
+  (VM vm) async {
+    await streamListen(vm, '_Echo');
+    try {
+      await streamListen(vm, '_Echo');
+      fail('Subscribed to stream twice');
+    } on ServerRpcException catch (e) {
+      expect(e.message, 'Stream already subscribed');
+    }
+  },
+  // Check double cancellation fails.
+  (VM vm) async {
+    await streamCancel(vm, '_Echo');
+    try {
+      await streamCancel(vm, '_Echo');
+      fail('Double cancellation of stream successful');
+    } on ServerRpcException catch (e) {
+      expect(e.message, 'Stream not subscribed');
+    }
+  },
+  // Check subscription to invalid stream fails.
+  (VM vm) async {
+    try {
+      await streamListen(vm, 'Foo');
+      fail('Subscribed to invalid stream');
+    } on ServerRpcException catch (e) {
+      expect(e.message, "streamListen: invalid 'streamId' parameter: Foo");
+    }
+  }
+];
+
+main(args) => runVMTests(args, tests);
diff --git a/runtime/observatory/tests/service/test_helper.dart b/runtime/observatory/tests/service/test_helper.dart
index 1dd59892c6e..e13bbb197ab 100644
--- a/runtime/observatory/tests/service/test_helper.dart
+++ b/runtime/observatory/tests/service/test_helper.dart
@@ -7,6 +7,7 @@ library test_helper;
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
+import 'package:dds/dds.dart';
 import 'package:observatory/service_io.dart';
 import 'package:test/test.dart';
 import 'service_test_common.dart';
@@ -16,6 +17,9 @@ export 'service_test_common.dart' show IsolateTest, VMTest;
 const bool useCausalAsyncStacks =
     const bool.fromEnvironment('dart.developer.causal_async_stacks');
 
+/// Determines whether DDS is enabled for this test run.
+const bool useDds = const bool.fromEnvironment('USE_DDS');
+
 /// The extra arguments to use
 const List<String> extraDebuggingArgs = useCausalAsyncStacks
     ? const ['--causal-async-stacks', '--no-lazy-async-stacks']
@@ -97,6 +101,8 @@ class _ServiceTesteeRunner {
 class _ServiceTesteeLauncher {
   Process process;
   final List<String> args;
+  Future<void> get exited => _processCompleter.future;
+  final _processCompleter = Completer<void>();
   bool killedByTester = false;
 
   _ServiceTesteeLauncher() : args = [Platform.script.toFilePath()] {}
@@ -286,6 +292,7 @@ class _ServiceTesteeLauncher {
           throw "Testee exited with $exitCode";
         }
         print("** Process exited");
+        _processCompleter.complete();
       });
 
       // Wait for the blank line which signals that we're ready to run.
@@ -295,9 +302,16 @@ class _ServiceTesteeLauncher {
       }
       final content = await serviceInfoFile.readAsString();
       final infoJson = json.decode(content);
-      uri = Uri.parse(infoJson['uri']);
+      String rawUri = infoJson['uri'];
+
+      // If rawUri ends with a /, Uri.parse will include an empty string as the
+      // last path segment. Make sure it's not there to ensure we have a
+      // consistent Uri.
+      if (rawUri.endsWith('/')) {
+        rawUri = rawUri.substring(0, rawUri.length - 1);
+      }
+      uri = Uri.parse(rawUri);
       completer.complete(uri);
-      print('** Signaled to run test queries on $uri');
     });
     return completer.future;
   }
@@ -314,7 +328,7 @@ class _ServiceTesteeLauncher {
 
 void setupAddresses(Uri serverAddress) {
   serviceWebsocketAddress =
-      'ws://${serverAddress.authority}${serverAddress.path}ws';
+      'ws://${serverAddress.authority}${serverAddress.path}/ws';
   serviceHttpAddress = 'http://${serverAddress.authority}${serverAddress.path}';
 }
 
@@ -331,16 +345,18 @@ class _ServiceTesterRunner {
     bool pause_on_unhandled_exceptions: false,
     bool enable_service_port_fallback: false,
     bool testeeControlsServer: false,
+    bool enableDds: true,
     int port = 0,
   }) {
     if (executableArgs == null) {
       executableArgs = Platform.executableArguments;
     }
-
-    final process = new _ServiceTesteeLauncher();
-    final name = Platform.script.pathSegments.last;
+    DartDevelopmentService dds;
     WebSocketVM vm;
+    _ServiceTesteeLauncher process;
+
     setUp(() async {
+      process = _ServiceTesteeLauncher();
       await process
           .launch(
               pause_on_start,
@@ -358,7 +374,15 @@ class _ServiceTesterRunner {
           print("Testee has pid $pid, waiting $wait before continuing");
           sleep(wait);
         }
-        setupAddresses(serverAddress);
+        if (useDds) {
+          dds = await DartDevelopmentService.startDartDevelopmentService(
+              serverAddress);
+          setupAddresses(dds.uri);
+        } else {
+          setupAddresses(serverAddress);
+        }
+        print('** Signaled to run test queries on $serviceHttpAddress'
+            ' (${useDds ? "DDS" : "VM Service"})');
         vm = new WebSocketVM(new WebSocketVMTarget(serviceWebsocketAddress));
         print('Loading VM...');
         await vm.load();
@@ -366,43 +390,66 @@ class _ServiceTesterRunner {
       });
     });
 
-    test(
-      name,
-      () async {
-        // Run vm tests.
-        if (vmTests != null) {
-          int testIndex = 1;
-          final totalTests = vmTests.length;
-          for (var test in vmTests) {
-            vm.verbose = verbose_vm;
-            print('Running $name [$testIndex/$totalTests]');
-            testIndex++;
-            await test(vm);
-          }
-        }
-
-        // Run isolate tests.
-        if (isolateTests != null) {
-          final isolate = await getFirstIsolate(vm);
-          int testIndex = 1;
-          final totalTests = isolateTests.length;
-          for (var test in isolateTests) {
-            vm.verbose = verbose_vm;
-            print('Running $name [$testIndex/$totalTests]');
-            testIndex++;
-            await test(isolate);
-          }
-        }
-      },
-      retry: 0,
-      // Some service tests run fairly long (e.g., valid_source_locations_test).
-      timeout: Timeout.none,
-    );
-
-    tearDown(() {
-      print('All service tests completed successfully.');
+    tearDown(() async {
+      if (useDds) {
+        await dds.shutdown();
+      }
       process.requestExit();
     });
+
+    final name = Platform.script.pathSegments.last;
+    runTest(String name) {
+      test(
+        '$name (${useDds ? 'DDS' : 'VM Service'})',
+        () async {
+          bool testsDone = false;
+          try {
+            // Run vm tests.
+            if (vmTests != null) {
+              int testIndex = 1;
+              final totalTests = vmTests.length;
+              for (var test in vmTests) {
+                vm.verbose = verbose_vm;
+                print('Running $name [$testIndex/$totalTests]');
+                testIndex++;
+                await test(vm);
+              }
+            }
+
+            // Run isolate tests.
+            if (isolateTests != null) {
+              final isolate = await getFirstIsolate(vm);
+              int testIndex = 1;
+              final totalTests = isolateTests.length;
+              for (var test in isolateTests) {
+                vm.verbose = verbose_vm;
+                print('Running $name [$testIndex/$totalTests]');
+                testIndex++;
+                await test(isolate);
+              }
+            }
+
+            print('All service tests completed successfully.');
+            testsDone = true;
+          } catch (error, stackTrace) {
+            if (testsDone) {
+              print('Ignoring late exception during process exit:\n'
+                  '$error\n$stackTrace');
+            } else {
+              rethrow;
+            }
+          }
+        },
+        // Some service tests run fairly long (e.g., valid_source_locations_test).
+        timeout: Timeout.none,
+      );
+    }
+
+    if (useDds && !enableDds) {
+      print('Skipping DDS run for $name');
+    } else {
+      runTest(name);
+    }
   }
 
   Future<Isolate> getFirstIsolate(WebSocketVM vm) async {
@@ -460,6 +507,7 @@ Future runIsolateTests(List<String> mainArgs, List<IsolateTest> tests,
     bool verbose_vm: false,
     bool pause_on_unhandled_exceptions: false,
     bool testeeControlsServer: false,
+    bool enableDds: true,
     List<String> extraArgs}) async {
   assert(!pause_on_start || testeeBefore == null);
   if (_isTestee()) {
@@ -477,7 +525,8 @@ Future runIsolateTests(List<String> mainArgs, List<IsolateTest> tests,
         pause_on_exit: pause_on_exit,
         verbose_vm: verbose_vm,
         pause_on_unhandled_exceptions: pause_on_unhandled_exceptions,
-        testeeControlsServer: testeeControlsServer);
+        testeeControlsServer: testeeControlsServer,
+        enableDds: enableDds);
   }
 }
 
@@ -529,6 +578,7 @@ Future runVMTests(List<String> mainArgs, List<VMTest> tests,
     bool verbose_vm: false,
     bool pause_on_unhandled_exceptions: false,
     bool enable_service_port_fallback: false,
+    bool enableDds: true,
     int port = 0,
     List<String> extraArgs,
     List<String> executableArgs}) async {
@@ -549,6 +599,7 @@ Future runVMTests(List<String> mainArgs, List<VMTest> tests,
       verbose_vm: verbose_vm,
       pause_on_unhandled_exceptions: pause_on_unhandled_exceptions,
       enable_service_port_fallback: enable_service_port_fallback,
+      enableDds: enableDds,
       port: port,
     );
   }
diff --git a/runtime/observatory/tests/service/verify_http_timeline_test.dart b/runtime/observatory/tests/service/verify_http_timeline_test.dart
index a555b118894..22fae9bd929 100644
--- a/runtime/observatory/tests/service/verify_http_timeline_test.dart
+++ b/runtime/observatory/tests/service/verify_http_timeline_test.dart
@@ -62,7 +62,7 @@ Uri randomlyAddRequestParams(Uri uri) {
 }
 
 Future<HttpServer> startServer() async {
-  final server = await HttpServer.bind(InternetAddress.loopbackIPv4, 8011);
+  final server = await HttpServer.bind(InternetAddress.loopbackIPv4, 0);
   server.listen((request) async {
     final response = request.response;
     randomlyAddCookie(response);
diff --git a/runtime/observatory/tests/service/vm_timeline_events_test.dart b/runtime/observatory/tests/service/vm_timeline_events_test.dart
index 1b77ed15c1c..a47bcf21aa2 100644
--- a/runtime/observatory/tests/service/vm_timeline_events_test.dart
+++ b/runtime/observatory/tests/service/vm_timeline_events_test.dart
@@ -9,10 +9,14 @@ import 'package:test/test.dart';
 import 'service_test_common.dart';
 import 'test_helper.dart';
 
-primeDartTimeline() {
+primeDartTimeline() async {
   while (true) {
     Timeline.startSync('apple');
     Timeline.finishSync();
+    // Give the VM a chance to send the timeline events. This test is
+    // significantly slower if we loop without yielding control after each
+    // iteration.
+    await Future.delayed(const Duration(milliseconds: 1));
   }
 }
 
@@ -22,8 +26,8 @@ List filterEvents(List events, filter) {
   return events.where(filter).toList();
 }
 
-Completer completer = new Completer();
-int eventCount = 0;
+Completer completer;
+int eventCount;
 
 onTimelineEvent(ServiceEvent event) {
   eventCount++;
@@ -34,6 +38,11 @@ onTimelineEvent(ServiceEvent event) {
 }
 
 var tests = <IsolateTest>[
+  (Isolate isolate) async {
+    // Clear global state.
+    eventCount = 0;
+    completer = Completer<void>();
+  },
   (Isolate isolate) async {
     // Subscribe to the Timeline stream.
     await subscribeToStream(isolate.vm, VM.kTimelineStream, onTimelineEvent);
diff --git a/sdk/lib/vmservice/vmservice.dart b/sdk/lib/vmservice/vmservice.dart
index 6943f130ba6..81a2ac7c8a7 100644
--- a/sdk/lib/vmservice/vmservice.dart
+++ b/sdk/lib/vmservice/vmservice.dart
@@ -49,7 +49,8 @@ final String serviceAuthToken = _makeAuthToken();
 final Map<int, IsolateEmbedderData> isolateEmbedderData =
     new Map<int, IsolateEmbedderData>();
 
-// These must be kept in sync with the declarations in vm/json_stream.h.
+// These must be kept in sync with the declarations in vm/json_stream.h and
+// pkg/dds/lib/src/stream_manager.dart.
 const kParseError = -32700;
 const kInvalidRequest = -32600;
 const kMethodNotFound = -32601;
diff --git a/sdk_nnbd/lib/vmservice/vmservice.dart b/sdk_nnbd/lib/vmservice/vmservice.dart
index f5a176e8b89..807fd000d31 100644
--- a/sdk_nnbd/lib/vmservice/vmservice.dart
+++ b/sdk_nnbd/lib/vmservice/vmservice.dart
@@ -46,7 +46,8 @@ final serviceAuthToken = _makeAuthToken();
 // the cleanup method will be invoked after being removed from the map.
 final isolateEmbedderData = <int, IsolateEmbedderData>{};
 
-// These must be kept in sync with the declarations in vm/json_stream.h.
+// These must be kept in sync with the declarations in vm/json_stream.h and
+// pkg/dds/lib/src/stream_manager.dart.
 const kParseError = -32700;
 const kInvalidRequest = -32600;
 const kMethodNotFound = -32601;
diff --git a/tools/bots/test_matrix.json b/tools/bots/test_matrix.json
index f92e6af018e..9a5b5d7ac9e 100644
--- a/tools/bots/test_matrix.json
+++ b/tools/bots/test_matrix.json
@@ -327,6 +327,7 @@
       "pkg/dart_internal/",
       "pkg/dart2native/",
       "pkg/dart2js_tools/",
+      "pkg/dds/",
       "pkg/expect/",
       "pkg/front_end/",
       "pkg/js/",
@@ -412,6 +413,7 @@
       "pkg/dart_internal/",
       "pkg/dart2native/",
       "pkg/dart2js_tools/",
+      "pkg/dds/",
       "pkg/expect/",
       "pkg/front_end/",
       "pkg/js/",