Bug 1195981 - When loading about:privatebrowsing, we fail to update the title of the tab intermittently. r=ttaubert

--HG--
extra : commitid : 5O6MZ6EUWtO
extra : rebase_source : 47690914f2c427c6764f0a6929b9f1f57c321877

browser/base/content/tabbrowser.xml

@@ -1843,7 +1843,10 @@
 
             // If we open a new tab with the newtab URL in the default
             // userContext, check if there is a preloaded browser ready.
-            if (aURI == BROWSER_NEW_TAB_URL && !aUserContextId) {
+            // Private windows are not included because both the label and the
+            // icon for the tab would be set incorrectly (see bug 1195981).
+            if (aURI == BROWSER_NEW_TAB_URL && !aUserContextId &&
+                !PrivateBrowsingUtils.isWindowPrivate(window)) {
               b = this._getPreloadedBrowser();
               usingPreloadedContent = !!b;
             }