Fix web size test for new world (#34063)

diff --git a/dev/devicelab/lib/tasks/perf_tests.dart b/dev/devicelab/lib/tasks/perf_tests.dart
index 13461de..8773706 100644
--- a/dev/devicelab/lib/tasks/perf_tests.dart
+++ b/dev/devicelab/lib/tasks/perf_tests.dart
@@ -239,7 +239,7 @@
     rmTree(sampleDir);
 
     await inDirectory<void>(Directory.systemTemp, () async {
-      await flutter('create', options: <String>['--template=app', sampleAppName]);
+      await flutter('create', options: <String>['--template=app', '--web', sampleAppName]);
       await inDirectory(sampleDir, () async {
         await flutter('packages', options: <String>['get']);
         await evalFlutter('build', options: <String>[
diff --git a/examples/hello_world/web/index.html b/examples/hello_world/web/index.html
new file mode 100644
index 0000000..8115fbb
--- /dev/null
+++ b/examples/hello_world/web/index.html
@@ -0,0 +1,12 @@
+<!-- Copyright 2019 The Chromium Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Hello, World</title>
+    </head>
+    <body>
+        <script src="main.dart.js"></script>
+    </body>
+</html>