Bug 791670 - part 2 - fix browser_bug763468_perwindowpb.js test; r=ehsan

browser/base/content/test/browser_bug763468_perwindowpb.js

@@ -13,9 +13,7 @@ function test() {
   let mode;
 
   function doTest(aIsPrivateMode, aWindow, aCallback) {
-    aWindow.BrowserOpenTab();
-    aWindow.gBrowser.selectedTab.linkedBrowser.addEventListener("load", function onLoad() {
-      aWindow.gBrowser.selectedTab.linkedBrowser.removeEventListener("load", onLoad, true);
+    whenNewTabLoaded(aWindow, function () {
       if (aIsPrivateMode) {
         mode = "per window private browsing";
         newTabURL = "about:privatebrowsing";
@@ -29,7 +27,7 @@ function test() {
 
       aWindow.gBrowser.removeTab(aWindow.gBrowser.selectedTab);
       aCallback()
-    }, true);
+    });
   };
 
   function testOnWindow(aOptions, aCallback) {

browser/base/content/test/head.js

@@ -197,6 +197,21 @@ function promiseIsURIVisited(aURI, aExpectedValue) {
   return deferred.promise;
 }
 
+function whenNewTabLoaded(aWindow, aCallback) {
+  aWindow.BrowserOpenTab();
+
+  let browser = aWindow.gBrowser.selectedBrowser;
+  if (browser.contentDocument.readyState === "complete") {
+    aCallback();
+    return;
+  }
+
+  browser.addEventListener("load", function onLoad() {
+    browser.removeEventListener("load", onLoad, true);
+    aCallback();
+  }, true);
+}
+
 function addVisits(aPlaceInfo, aCallback) {
   let places = [];
   if (aPlaceInfo instanceof Ci.nsIURI) {