WebSocket client for VM service

runtime/bin/vmservice/client.dart

Index: runtime/bin/vmservice/client.dart
diff --git a/runtime/bin/vmservice/client.dart b/runtime/bin/vmservice/client.dart
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+// Copyright (c) 2013, 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 vmservice;
+
+// A service client.
+abstract class Client {
+  /// Port that lives as long as the network client.
+  final RawReceivePort receivePort = new RawReceivePort();
+  final VMService service;
+
+  Client(this.service) {
+    receivePort.handler = (response) {
+      post(null, response);
+    };
+    service._addClient(this);
+  }
+
+  /// When implementing, call [close] when the network connection closes.
+  void close() {
+    receivePort.close();
+    service._removeClient(this);
+  }
+
+  /// Call to process a message. Response will be posted with 'seq'.
+  void onMessage(var seq, Message message) {
+    // Call post when the response arrives.
+    message.response.then((response) {
+      post(seq, response);
+    });
+    // Send message to service.
+    service.route(message);
+  }
+
+  /// When implementing, responsible for sending [response] to the client.
+  void post(var seq, String response);
+
+  dynamic toJson() {
+    return {
+    };
+  }
+}