diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_970511_undo_restore_default.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_970511_undo_restore_default.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,107 @@
+/* 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/. */
+
+"use strict";
+
+// Restoring default should show an "undo" option which undoes the restoring operation.
+add_task(function() {
+  let homeButtonId = "home-button";
+  CustomizableUI.removeWidgetFromArea(homeButtonId);
+  yield startCustomizing();
+  ok(!CustomizableUI.inDefaultState, "Not in default state to begin with");
+  is(CustomizableUI.getPlacementOfWidget(homeButtonId), null, "Home button is in palette");
+  let undoResetButton = document.getElementById("customization-undo-reset-button");
+  is(undoResetButton.hidden, true, "The undo button is hidden before reset");
+
+  yield gCustomizeMode.reset();
+
+  ok(CustomizableUI.inDefaultState, "In default state after reset");
+  is(undoResetButton.hidden, false, "The undo button is visible after reset");
+
+  undoResetButton.click();
+  yield waitForCondition(function() !gCustomizeMode.resetting);
+  ok(!CustomizableUI.inDefaultState, "Not in default state after reset-undo");
+  is(undoResetButton.hidden, true, "The undo button is hidden after clicking on the undo button");
+  is(CustomizableUI.getPlacementOfWidget(homeButtonId), null, "Home button is in palette");
+
+  yield gCustomizeMode.reset();
+});
+
+// Performing an action after a reset will hide the reset button.
+add_task(function() {
+  let homeButtonId = "home-button";
+  CustomizableUI.removeWidgetFromArea(homeButtonId);
+  ok(!CustomizableUI.inDefaultState, "Not in default state to begin with");
+  is(CustomizableUI.getPlacementOfWidget(homeButtonId), null, "Home button is in palette");
+  let undoResetButton = document.getElementById("customization-undo-reset-button");
+  is(undoResetButton.hidden, true, "The undo button is hidden before reset");
+
+  yield gCustomizeMode.reset();
+
+  ok(CustomizableUI.inDefaultState, "In default state after reset");
+  is(undoResetButton.hidden, false, "The undo button is visible after reset");
+
+  CustomizableUI.addWidgetToArea(homeButtonId, CustomizableUI.AREA_PANEL);
+  is(undoResetButton.hidden, true, "The undo button is hidden after another change");
+});
+
+// "Restore defaults", exiting customize, and re-entering shouldn't show the Undo button
+add_task(function() {
+  let undoResetButton = document.getElementById("customization-undo-reset-button");
+  is(undoResetButton.hidden, true, "The undo button is hidden before a reset");
+  ok(!CustomizableUI.inDefaultState, "The browser should not be in default state");
+  yield gCustomizeMode.reset();
+
+  is(undoResetButton.hidden, false, "The undo button is visible after a reset");
+  yield endCustomizing();
+  yield startCustomizing();
+  is(undoResetButton.hidden, true, "The undo reset button should be hidden after entering customization mode");
+});
+
+// Bug 971626 - Restore Defaults should collapse the Title Bar
+add_task(function() {
+  if (Services.appinfo.OS != "WINNT" &&
+      Services.appinfo.OS != "Darwin") {
+    return;
+  }
+  let prefName = "browser.tabs.drawInTitlebar";
+  let defaultValue = Services.prefs.getBoolPref(prefName);
+  let restoreDefaultsButton = document.getElementById("customization-reset-button");
+  let titleBarButton = document.getElementById("customization-titlebar-visibility-button");
+  let undoResetButton = document.getElementById("customization-undo-reset-button");
+  ok(CustomizableUI.inDefaultState, "Should be in default state at start of test");
+  ok(restoreDefaultsButton.disabled, "Restore defaults button should be disabled when in default state");
+  is(titleBarButton.hasAttribute("checked"), !defaultValue, "Title bar button should reflect pref value");
+  is(undoResetButton.hidden, true, "Undo reset button should be hidden at start of test");
+
+  Services.prefs.setBoolPref(prefName, !defaultValue);
+  ok(!restoreDefaultsButton.disabled, "Restore defaults button should be enabled when pref changed");
+  is(titleBarButton.hasAttribute("checked"), defaultValue, "Title bar button should reflect changed pref value");
+  ok(!CustomizableUI.inDefaultState, "With titlebar flipped, no longer default");
+  is(undoResetButton.hidden, true, "Undo reset button should be hidden after pref change");
+
+  yield gCustomizeMode.reset();
+  ok(restoreDefaultsButton.disabled, "Restore defaults button should be disabled after reset");
+  is(titleBarButton.hasAttribute("checked"), !defaultValue, "Title bar button should reflect default value after reset");
+  is(Services.prefs.getBoolPref(prefName), defaultValue, "Reset should reset drawInTitlebar");
+  ok(CustomizableUI.inDefaultState, "In default state after titlebar reset");
+  is(undoResetButton.hidden, false, "Undo reset button should be visible after reset");
+  ok(!undoResetButton.disabled, "Undo reset button should be enabled after reset");
+
+  yield gCustomizeMode.undoReset();
+  ok(!restoreDefaultsButton.disabled, "Restore defaults button should be enabled after undo-reset");
+  is(titleBarButton.hasAttribute("checked"), defaultValue, "Title bar button should reflect undo-reset value");
+  ok(!CustomizableUI.inDefaultState, "No longer in default state after undo");
+  is(Services.prefs.getBoolPref(prefName), !defaultValue, "Undo-reset goes back to previous pref value");
+  is(undoResetButton.hidden, true, "Undo reset button should be hidden after undo-reset clicked");
+
+  Services.prefs.clearUserPref(prefName);
+  ok(CustomizableUI.inDefaultState, "In default state after pref cleared");
+  is(undoResetButton.hidden, true, "Undo reset button should be hidden at end of test");
+});
+
+add_task(function asyncCleanup() {
+  yield gCustomizeMode.reset();
+  yield endCustomizing();
+});