Add support for ie11 in our testing scripts

tools/testing/dart/browser_controller.dart

 // Copyright (c) 2013, 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 browser;
 
 import "dart:async";
 import "dart:convert" show LineSplitter, UTF8;
 import "dart:core";
 import "dart:io";
 
@@ skipping 62 matching lines @@
     } else if (name.startsWith('ie')) {
       browser = new IE();
     } else {
       throw "Non supported browser";
     }
     browser._binary = executablePath;
     return browser;
   }
 
   static const List<String> SUPPORTED_BROWSERS =
-    const ['safari', 'ff', 'firefox', 'chrome', 'ie9', 'ie10', 'dartium'];
+    const ['safari', 'ff', 'firefox', 'chrome', 'ie9', 'ie10',
+           'ie11', 'dartium'];
 
   static const List<String> BROWSERS_WITH_WINDOW_SUPPORT = const [];
 
   // TODO(kustermann): add standard support for chrome on android
   static bool supportedBrowser(String name) {
     return SUPPORTED_BROWSERS.contains(name);
   }
 
   void _logEvent(String event) {
     String toLog = "$this ($id) - $event \n";
@@ skipping 1358 matching lines @@
     Dart test driver, number of tests: <div id="number"></div><br>
     Currently executing: <div id="currently_executing"></div><br>
     Unhandled error: <div id="unhandled_error"></div>
     <iframe id="embedded_iframe"></iframe>
   </body>
 </html>
 """;
     return driverContent;
   }
 }