Support asynchronous main methods.

lib/src/runner/browser/iframe_listener.dart

 // 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.
 
 library test.runner.browser.iframe_listener;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html' hide Metadata;
 
@@ skipping 38 matching lines @@
 
     if (main is! Function) {
       _sendLoadException(channel, "Top-level main getter is not a function.");
       return;
     } else if (main is! AsyncFunction) {
       _sendLoadException(channel, "Top-level main() function takes arguments.");
       return;
     }
 
     var declarer = new Declarer();
-    try {
-      runZoned(main, zoneValues: {#test.declarer: declarer});
-    } catch (error, stackTrace) {
+    runZoned(() => new Future.sync(main), zoneValues: {
+      #test.declarer: declarer
+    }).then((_) {
+      var url = Uri.parse(window.location.href);
+      var message = JSON.decode(Uri.decodeFull(url.fragment));
+      var metadata = new Metadata.deserialize(message['metadata']);
+      var browser = TestPlatform.find(message['browser']);
+
+      var suite = new Suite(declarer.tests, metadata: metadata)
+          .forPlatform(browser);
+      new IframeListener._(suite)._listen(channel);
+    }, onError: (error, stackTrace) {
       channel.sink.add({
         "type": "error",
         "error": RemoteException.serialize(error, stackTrace)
       });
-      return;
-    }
-
-    var url = Uri.parse(window.location.href);
-    var message = JSON.decode(Uri.decodeFull(url.fragment));
-    var metadata = new Metadata.deserialize(message['metadata']);
-    var browser = TestPlatform.find(message['browser']);
-
-    var suite = new Suite(declarer.tests, metadata: metadata)
-        .forPlatform(browser);
-    new IframeListener._(suite)._listen(channel);
+    });
   }
 
   /// Constructs a [MultiChannel] wrapping the `postMessage` communication with
   /// the host page.
   ///
   /// This [MultiChannel] corresponds to a [MultiChannel] in the server's
   /// [IframeTest] class.
   static MultiChannel _postMessageChannel() {
     var inputController = new StreamController(sync: true);
     var outputController = new StreamController(sync: true);
@@ skipping 80 matching lines @@
     });
 
     liveTest.onPrint.listen((line) {
       print(line);
       channel.sink.add({"type": "print", "line": line});
     });
 
     liveTest.run().then((_) => channel.sink.add({"type": "complete"}));
   }
 }