Bug 963945 - Add about:addons URI as whitelisted so that it can be refocused instead of opening duplicate tabs in private browsing. r=jdm

browser/base/content/browser.js

@@ -7476,6 +7476,7 @@ function switchToTabHavingURI(aURI, aOpenNew, aOpenParams={}) {
   // Certain URLs can be switched to irrespective of the source or destination
   // window being in private browsing mode:
   const kPrivateBrowsingWhitelist = new Set([
+    "about:addons",
     "about:customizing",
   ]);
 

browser/base/content/test/general/browser.ini

@@ -486,3 +486,4 @@ skip-if = e10s # bug 1100687 - test directly manipulates content (content.docume
 [browser_mcb_redirect.js]
 skip-if = e10s # bug 1084504 - [e10s] Mixed content detection does not take redirection into account
 [browser_windowactivation.js]
+[browser_bug963945.js]

browser/base/content/test/general/browser_bug963945.js

@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This test ensures the about:addons tab is only
+ * opened one time when in private browsing.
+ */
+
+function test() {
+  waitForExplicitFinish();
+	
+  var win = OpenBrowserWindow({private: true});
+
+  whenDelayedStartupFinished(win, function() {
+    win.gBrowser.loadURI("about:addons");
+
+    waitForFocus(function() {
+      EventUtils.synthesizeKey("a", { ctrlKey: true, shiftKey: true }, win);
+
+      is(win.gBrowser.tabs.length, 1, "about:addons tab was re-focused.");
+      is(win.gBrowser.currentURI.spec, "about:addons", "Addons tab was opened.");
+
+      win.close();
+      finish();    
+    });
+  });
+}
+
+