Bug 1270704 - Fix intermittent dead CPOW failure in browser_browserLoaded_content_loaded.js. r=mconley, a=test-only

--HG--
extra : source : ffb62c341a4411407804e5dea24e406eb17c7028
extra : intermediate-source : c1c3b1e2bf94289422620f27e546a42091f01f98
extra : histedit_source : 1a21f91dc5e0fae6e8b4a97571cc98fafa06e2b7%2Cbedb6ab3bd200276ce3c250fcdccd9dc9bb7abcc

testing/mochitest/tests/browser/browser_browserLoaded_content_loaded.js

@@ -2,9 +2,11 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 'use strict';
 
-// Check if the browser has loaded by checking ready state of the DOM.
-function isDOMLoaded(aBrowser) {
-  return aBrowser.contentWindowAsCPOW.document.readyState === 'complete';
+function isDOMLoaded(browser) {
+  return ContentTask.spawn(browser, null, function*() {
+    Assert.equal(content.document.readyState, "complete",
+      "Browser should be loaded.");
+  });
 }
 
 // It checks if calling BrowserTestUtils.browserLoaded() yields
@@ -13,7 +15,7 @@ add_task(function*() {
   let tab = gBrowser.addTab('http://example.com');
   let browser = tab.linkedBrowser;
   yield BrowserTestUtils.browserLoaded(browser);
-  Assert.ok(isDOMLoaded(browser), 'browser', 'Expect browser to have loaded.');
+  yield isDOMLoaded(browser);
   gBrowser.removeTab(tab);
 });
 
@@ -34,7 +36,9 @@ add_task(function*() {
     for (b of browsers) BrowserTestUtils.browserLoaded(b)
   ));
   let expected = 'Expected all promised browsers to have loaded.';
-  Assert.ok(browsers.every(isDOMLoaded), expected);
+  for (var browser of browsers) {
+    yield isDOMLoaded(browser);
+  }
   //cleanup
   browsers
     .map(browser => gBrowser.getTabForBrowser(browser))