Add in-process http server to the dart test scripts.

tools/testing/dart/http_server.dart

+// Copyright (c) 2012, 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.
+
+#library('http_server');
+
+#import('dart:io');
+#import('test_suite.dart');  // For TestUtils.
+
+HttpServer _httpServer;
+
+startHttpServer(String host, int port) {
+  var basePath = TestUtils.dartDir();
+  _httpServer = new HttpServer();
+  _httpServer.onError = (e) {
+    // Consider errors in the builtin http server fatal.
+    // Intead of just throwing the exception we print
+    // a message that makes it clearer what happened.
+    print('Test http server error: $e');
+    exit(1);
+  };
+  _httpServer.defaultRequestHandler = (request, resp) {
+    var requestPath = new Path(request.path).canonicalize();
+    if (!requestPath.isAbsolute) {
+      resp.statusCode = HttpStatus.NOT_FOUND;
+      resp.outputStream.close();
+    } else {
+      var path = basePath;
+      requestPath.segments().forEach((s) => path = path.append(s));
+      var file = new File(path.toNativePath());
+      file.exists().then((exists) {
+        if (exists) {
+          // Allow loading from localhost in browsers.
+          resp.headers.set("Access-Control-Allow-Origin", "*");
+          file.openInputStream().pipe(resp.outputStream);
+        } else {
+          resp.statusCode = HttpStatus.NOT_FOUND;
+          resp.outputStream.close();
+        }
+      });
+    }
+  };
+  _httpServer.listen(host, port);
+}
+
+terminateHttpServer() {
+  _httpServer.close();
+}