Load web tests using the plugin infrastructure.

lib/src/runner/browser/post_message_channel.dart

Index: lib/src/runner/browser/post_message_channel.dart
diff --git a/lib/src/runner/browser/post_message_channel.dart b/lib/src/runner/browser/post_message_channel.dart
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+++ b/lib/src/runner/browser/post_message_channel.dart
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+// Copyright (c) 2015, 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 'dart:convert';
+import 'dart:html';
+
+import 'package:stream_channel/stream_channel.dart';
+
+/// Constructs a [StreamChannel] wrapping `postMessage` communication with the
+/// host page.
+StreamChannel postMessageChannel() {
+  var controller = new StreamChannelController(sync: true);
+
+  window.onMessage.listen((message) {
+    // A message on the Window can theoretically come from any website. It's
+    // very unlikely that a malicious site would care about hacking someone's
+    // unit tests, let alone be able to find the test server while it's
+    // running, but it's good practice to check the origin anyway.
+    if (message.origin != window.location.origin) return;
+    message.stopPropagation();
+
+    // See host.dart for why we have to explicitly decode here.
+    controller.local.sink.add(JSON.decode(message.data));
+  });
+
+  controller.local.stream.listen((data) {
+    // TODO(nweiz): Stop manually adding href here once issue 22554 is
+    // fixed.
+    window.parent.postMessage({
+      "href": window.location.href,
+      "data": data
+    }, window.location.origin);
+  });
+
+  // Send a ready message once we're listening so the host knows it's safe to
+  // start sending events.
+  window.parent.postMessage({
+    "href": window.location.href,
+    "ready": true
+  }, window.location.origin);
+
+  return controller.foreign;
+}