Transition to new API to start Dart.

client/testing/unittest/test_controller.js

 // Copyright (c) 2011, 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.
 
 /**
  * Test controller logic - used by unit test harness to embed tests in
  * DumpRenderTree.
  */
 
+if (navigator.webkitStartDart) {
+  navigator.webkitStartDart();
+}
+
 function processMessage(msg) {
   if (window.layoutTestController) {
     if (msg == 'unittest-suite-done') {
       window.layoutTestController.notifyDone();
     } else if (msg == 'unittest-suite-wait-for-done') {
       window.layoutTestController.startedDartTest = true;
     }
   }
 }
 
@@ skipping 12 matching lines @@
   if (window.compilationError) {
     var element = document.createElement('pre');
     element.innerHTML = window.compilationError;
     document.body.appendChild(element);
     window.layoutTestController.notifyDone();
     return;
   }
 }
 
 window.addEventListener("DOMContentLoaded", onLoad, false);