Reset http-parser instead of only setting _state, when we have handled a full request-response conv…

tests/standalone/io/http_keep_alive_test.dart

+// 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.
+//
+// VMOptions=
+// VMOptions=--short_socket_read
+// VMOptions=--short_socket_write
+// VMOptions=--short_socket_read --short_socket_write
+
+import "dart:async";
+import "dart:io";
+
+Future getData(HttpClient client, int port, bool chunked, int length) {
+  return client.get("localhost", port, "/?chunked=$chunked&length=$length")
+      .then((request) => request.close())
+      .then((response) {
+        return response.reduce(0, (bytes, data) => bytes + data.length)
+            .then((bytes) {
+              Expect.equals(length, bytes);
+            });
+      });
+}
+
+Future<HttpServer> startServer() {
+  return HttpServer.bind("127.0.0.1", 0).then((server) {
+    server.listen((request) {
+      bool chunked = request.queryParameters["chunked"] == "true";
+      int length = int.parse(request.queryParameters["length"]);
+      var buffer = new List.fixedLength(length, fill: 0);
+      if (!chunked) request.response.contentLength = length;
+      request.response.add(buffer);
+      request.response.close();
+    });
+    return server;
+  });
+}
+
+testKeepAliveNonChunked() {
+  startServer().then((server) {
+    var client = new HttpClient();
+
+    getData(client, server.port, false, 100)
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) {
+          server.close();
+          client.close();
+        });
+
+  });
+}
+
+testKeepAliveChunked() {
+  startServer().then((server) {
+    var client = new HttpClient();
+
+    getData(client, server.port, true, 100)
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) {
+          server.close();
+          client.close();
+        });
+
+  });
+}
+
+testKeepAliveMixed() {
+  startServer().then((server) {
+    var client = new HttpClient();
+
+    getData(client, server.port, true, 100)
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) => getData(client, server.port, true, 100))
+        .then((_) => getData(client, server.port, false, 100))
+        .then((_) {
+          server.close();
+          client.close();
+        });
+
+  });
+}
+
+void main() {
+  testKeepAliveNonChunked();
+  testKeepAliveChunked();
+  testKeepAliveMixed();
+}