Display a pause screen in a paused browser.

lib/src/runner/browser/static/host.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.host;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
 import 'dart:js' as js;
@@ skipping 63 matching lines @@
   var testRunner = js.context['testRunner'];
   if (testRunner != null) testRunner.callMethod('waitUntilDone', []);
 
   runZoned(() {
     var serverChannel = _connectToServer();
     serverChannel.stream.listen((message) {
       if (message['command'] == 'loadSuite') {
         var suiteChannel = serverChannel.virtualChannel(message['channel']);
         var iframeChannel = _connectToIframe(message['url'], message['id']);
         suiteChannel.pipe(iframeChannel);
+      } else if (message['command'] == 'displayPause') {
+        document.body.classes.add('paused');
+      } else if (message['command'] == 'resume') {
+        document.body.classes.remove('paused');
       } else {
         assert(message['command'] == 'closeSuite');
         _iframes[message['id']].remove();
       }
     });
+
+    var play = document.querySelector("#play");
+    play.onClick.listen((_) {
+      document.body.classes.remove('paused');
+      serverChannel.sink.add({"command": "resume"});
+    });
   }, onError: (error, stackTrace) {
     print("$error\n${new Trace.from(stackTrace).terse}");
   });
 }
 
 /// Creates a [MultiChannel] connection to the server, using a [WebSocket] as
 /// the underlying protocol.
 MultiChannel _connectToServer() {
   // The `managerUrl` query parameter contains the WebSocket URL of the remote
   // [BrowserManager] with which this communicates.
   var currentUrl = Uri.parse(window.location.href);
   var webSocket = new WebSocket(currentUrl.queryParameters['managerUrl']);
 
   var inputController = new StreamController(sync: true);
-  webSocket.onMessage.listen(
-      (message) => inputController.add(JSON.decode(message.data)));
+  webSocket.onMessage.listen((message) {
+    inputController.add(JSON.decode(message.data));
+  });
 
   var outputController = new StreamController(sync: true);
   outputController.stream.listen(
       (message) => webSocket.send(JSON.encode(message)));
 
   return new MultiChannel(inputController.stream, outputController.sink);
 }
 
 /// Creates an iframe with `src` [url] and establishes a connection to it using
 /// `postMessage`.
@@ skipping 30 matching lines @@
     if (!readyCompleter.isCompleted) readyCompleter.complete();
   });
 
   outputController.stream.listen((message) async {
     await readyCompleter.future;
     iframe.contentWindow.postMessage(message, window.location.origin);
   });
 
   return new StreamChannel(inputController.stream, outputController.sink);
 }