Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-19 00:47:55 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-19 00:47:55 +0000
commit: 26a029d407be480d791972afb5975cf62c9360a6 (patch)
tree: f435a8308119effd964b339f76abb83a57c29483 /browser/modules/test
parent: Initial commit. (diff)
download: firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
52 files changed, 13608 insertions, 0 deletions
diff --git a/browser/modules/test/browser/blank_iframe.html b/browser/modules/test/browser/blank_iframe.html
new file mode 100644
index 0000000000..88cd26088f
--- /dev/null
+++ b/browser/modules/test/browser/blank_iframe.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+  </head>
+  <body><iframe></iframe></body>
+</html>
diff --git a/browser/modules/test/browser/browser.toml b/browser/modules/test/browser/browser.toml
new file mode 100644
index 0000000000..21b3cdf18c
--- /dev/null
+++ b/browser/modules/test/browser/browser.toml
@@ -0,0 +1,87 @@
+[DEFAULT]
+support-files = ["head.js"]
+prefs = ["telemetry.number_of_site_origin.min_interval=0"]
+
+["browser_BrowserWindowTracker.js"]
+
+["browser_EveryWindow.js"]
+
+["browser_HomePage_add_button.js"]
+
+["browser_PageActions.js"]
+
+["browser_PageActions_contextMenus.js"]
+
+["browser_PageActions_newWindow.js"]
+
+["browser_PermissionUI.js"]
+
+["browser_PermissionUI_prompts.js"]
+
+["browser_ProcessHangNotifications.js"]
+
+["browser_SitePermissions.js"]
+
+["browser_SitePermissions_combinations.js"]
+
+["browser_SitePermissions_expiry.js"]
+
+["browser_SitePermissions_tab_urls.js"]
+https_first_disabled = true
+
+["browser_TabUnloader.js"]
+support-files = [
+  "file_webrtc.html",
+  "../../../base/content/test/tabs/dummy_page.html",
+  "../../../base/content/test/tabs/file_mediaPlayback.html",
+  "../../../base/content/test/general/audio.ogg",
+]
+
+["browser_Telemetry_numberOfSiteOrigins.js"]
+support-files = ["contain_iframe.html"]
+
+["browser_Telemetry_numberOfSiteOriginsPerDocument.js"]
+support-files = [
+  "contain_iframe.html",
+  "blank_iframe.html",
+]
+
+["browser_UnsubmittedCrashHandler.js"]
+run-if = ["crashreporter"]
+
+["browser_UsageTelemetry.js"]
+https_first_disabled = true
+
+["browser_UsageTelemetry_content_aboutRestartRequired.js"]
+
+["browser_UsageTelemetry_domains.js"]
+https_first_disabled = true
+
+["browser_UsageTelemetry_interaction.js"]
+https_first_disabled = true
+
+["browser_UsageTelemetry_private_and_restore.js"]
+https_first_disabled = true
+skip-if = ["verify && debug"]
+
+["browser_UsageTelemetry_toolbars.js"]
+
+["browser_UsageTelemetry_uniqueOriginsVisitedInPast24Hours.js"]
+https_first_disabled = true
+
+["browser_preloading_tab_moving.js"]
+skip-if = ["os == 'linux' && tsan"] # Bug 1720203
+
+["browser_taskbar_preview.js"]
+skip-if = [
+  "os != 'win'",               # bug 1456807
+  "os == 'win' && bits == 64", # bug 1456807
+]
+
+["browser_urlBar_zoom.js"]
+skip-if = [
+  "os == 'mac'", # Bug 1528429
+  "os == 'linux' && bits == 64 && os_version == '18.04'", # Bug 1619835
+  "win10_2009 && bits == 64",           # Bug 1619835
+  "win11_2009 && bits == 32 && debug", # Bug 1619835
+]
diff --git a/browser/modules/test/browser/browser_BrowserWindowTracker.js b/browser/modules/test/browser/browser_BrowserWindowTracker.js
new file mode 100644
index 0000000000..ea6f75c0e3
--- /dev/null
+++ b/browser/modules/test/browser/browser_BrowserWindowTracker.js
@@ -0,0 +1,234 @@
+"use strict";
+
+const TEST_WINDOW = window;
+
+function windowActivated(win) {
+  if (Services.ww.activeWindow == win) {
+    return Promise.resolve();
+  }
+  return BrowserTestUtils.waitForEvent(win, "activate");
+}
+
+async function withOpenWindows(amount, cont) {
+  let windows = [];
+  for (let i = 0; i < amount; ++i) {
+    let win = await BrowserTestUtils.openNewBrowserWindow();
+    await windowActivated(win);
+    windows.push(win);
+  }
+  await cont(windows);
+  await Promise.all(
+    windows.map(window => BrowserTestUtils.closeWindow(window))
+  );
+}
+
+add_task(async function test_getTopWindow() {
+  await withOpenWindows(5, async function (windows) {
+    // Without options passed in.
+    let window = BrowserWindowTracker.getTopWindow();
+    let expectedMostRecentIndex = windows.length - 1;
+    Assert.equal(
+      window,
+      windows[expectedMostRecentIndex],
+      "Last opened window should be the most recent one."
+    );
+
+    // Mess with the focused window things a bit.
+    for (let idx of [3, 1]) {
+      let promise = BrowserTestUtils.waitForEvent(windows[idx], "activate");
+      Services.focus.focusedWindow = windows[idx];
+      await promise;
+      window = BrowserWindowTracker.getTopWindow();
+      Assert.equal(
+        window,
+        windows[idx],
+        "Lastly focused window should be the most recent one."
+      );
+      // For this test it's useful to keep the array of created windows in order.
+      windows.splice(idx, 1);
+      windows.push(window);
+    }
+    // Update the pointer to the most recent opened window.
+    expectedMostRecentIndex = windows.length - 1;
+
+    // With 'private' option.
+    window = BrowserWindowTracker.getTopWindow({ private: true });
+    Assert.equal(window, null, "No private windows opened yet.");
+    window = BrowserWindowTracker.getTopWindow({ private: 1 });
+    Assert.equal(window, null, "No private windows opened yet.");
+    windows.push(
+      await BrowserTestUtils.openNewBrowserWindow({ private: true })
+    );
+    ++expectedMostRecentIndex;
+    window = BrowserWindowTracker.getTopWindow({ private: true });
+    Assert.equal(
+      window,
+      windows[expectedMostRecentIndex],
+      "Private window available."
+    );
+    window = BrowserWindowTracker.getTopWindow({ private: 1 });
+    Assert.equal(
+      window,
+      windows[expectedMostRecentIndex],
+      "Private window available."
+    );
+    // Private window checks seems to mysteriously fail on Linux in this test.
+    if (AppConstants.platform != "linux") {
+      window = BrowserWindowTracker.getTopWindow({ private: false });
+      Assert.equal(
+        window,
+        windows[expectedMostRecentIndex - 1],
+        "Private window available, but should not be returned."
+      );
+    }
+
+    // With 'allowPopups' option.
+    window = BrowserWindowTracker.getTopWindow({ allowPopups: true });
+    Assert.equal(
+      window,
+      windows[expectedMostRecentIndex],
+      "Window focused before the private window should be the most recent one."
+    );
+    window = BrowserWindowTracker.getTopWindow({ allowPopups: false });
+    Assert.equal(
+      window,
+      windows[expectedMostRecentIndex],
+      "Window focused before the private window should be the most recent one."
+    );
+    let popupWindowPromise = BrowserTestUtils.waitForNewWindow();
+    SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
+      let features =
+        "location=no, personalbar=no, toolbar=no, scrollbars=no, menubar=no, status=no";
+      content.window.open("about:blank", "_blank", features);
+    });
+    let popupWindow = await popupWindowPromise;
+    await windowActivated(popupWindow);
+    window = BrowserWindowTracker.getTopWindow({ allowPopups: true });
+    Assert.equal(
+      window,
+      popupWindow,
+      "The popup window should be the most recent one, when requested."
+    );
+    window = BrowserWindowTracker.getTopWindow({ allowPopups: false });
+    Assert.equal(
+      window,
+      windows[expectedMostRecentIndex],
+      "Window focused before the popup window should be the most recent one."
+    );
+    popupWindow.close();
+  });
+});
+
+add_task(async function test_orderedWindows() {
+  await withOpenWindows(10, async function (windows) {
+    Assert.equal(
+      BrowserWindowTracker.windowCount,
+      11,
+      "Number of tracked windows, including the test window"
+    );
+    let ordered = BrowserWindowTracker.orderedWindows.filter(
+      w => w != TEST_WINDOW
+    );
+    Assert.deepEqual(
+      [9, 8, 7, 6, 5, 4, 3, 2, 1, 0],
+      ordered.map(w => windows.indexOf(w)),
+      "Order of opened windows should be as opened."
+    );
+
+    // Mess with the focused window things a bit.
+    for (let idx of [4, 6, 1]) {
+      let promise = BrowserTestUtils.waitForEvent(windows[idx], "activate");
+      Services.focus.focusedWindow = windows[idx];
+      await promise;
+    }
+
+    let ordered2 = BrowserWindowTracker.orderedWindows.filter(
+      w => w != TEST_WINDOW
+    );
+    // After the shuffle, we expect window '1' to be the top-most window, because
+    // it was the last one we called focus on. Then '6', the window we focused
+    // before-last, followed by '4'. The order of the other windows remains
+    // unchanged.
+    let expected = [1, 6, 4, 9, 8, 7, 5, 3, 2, 0];
+    Assert.deepEqual(
+      expected,
+      ordered2.map(w => windows.indexOf(w)),
+      "After shuffle of focused windows, the order should've changed."
+    );
+  });
+});
+
+add_task(async function test_pendingWindows() {
+  Assert.equal(
+    BrowserWindowTracker.windowCount,
+    1,
+    "Number of tracked windows, including the test window"
+  );
+
+  let pending = BrowserWindowTracker.getPendingWindow();
+  Assert.equal(pending, null, "Should be no pending window");
+
+  let expectedWin = BrowserWindowTracker.openWindow();
+  pending = BrowserWindowTracker.getPendingWindow();
+  Assert.ok(pending, "Should be a pending window now.");
+  Assert.ok(
+    !BrowserWindowTracker.getPendingWindow({ private: true }),
+    "Should not be a pending private window"
+  );
+  Assert.equal(
+    pending,
+    BrowserWindowTracker.getPendingWindow({ private: false }),
+    "Should be the same non-private window pending"
+  );
+
+  let foundWin = await pending;
+  Assert.equal(foundWin, expectedWin, "Should have found the right window");
+  Assert.ok(
+    !BrowserWindowTracker.getPendingWindow(),
+    "Should be no pending window now."
+  );
+
+  await BrowserTestUtils.closeWindow(foundWin);
+
+  expectedWin = BrowserWindowTracker.openWindow({ private: true });
+  pending = BrowserWindowTracker.getPendingWindow();
+  Assert.ok(pending, "Should be a pending window now.");
+  Assert.ok(
+    !BrowserWindowTracker.getPendingWindow({ private: false }),
+    "Should not be a pending non-private window"
+  );
+  Assert.equal(
+    pending,
+    BrowserWindowTracker.getPendingWindow({ private: true }),
+    "Should be the same private window pending"
+  );
+
+  foundWin = await pending;
+  Assert.equal(foundWin, expectedWin, "Should have found the right window");
+  Assert.ok(
+    !BrowserWindowTracker.getPendingWindow(),
+    "Should be no pending window now."
+  );
+
+  await BrowserTestUtils.closeWindow(foundWin);
+
+  expectedWin = Services.ww.openWindow(
+    null,
+    AppConstants.BROWSER_CHROME_URL,
+    "_blank",
+    "chrome,dialog=no,all",
+    null
+  );
+  BrowserWindowTracker.registerOpeningWindow(expectedWin, false);
+  pending = BrowserWindowTracker.getPendingWindow();
+  Assert.ok(pending, "Should be a pending window now.");
+
+  foundWin = await pending;
+  Assert.equal(foundWin, expectedWin, "Should have found the right window");
+  Assert.ok(
+    !BrowserWindowTracker.getPendingWindow(),
+    "Should be no pending window now."
+  );
+
+  await BrowserTestUtils.closeWindow(foundWin);
+});
diff --git a/browser/modules/test/browser/browser_EveryWindow.js b/browser/modules/test/browser/browser_EveryWindow.js
new file mode 100644
index 0000000000..de1a7bbf9a
--- /dev/null
+++ b/browser/modules/test/browser/browser_EveryWindow.js
@@ -0,0 +1,161 @@
+/* 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";
+
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+
+const { EveryWindow } = ChromeUtils.importESModule(
+  "resource:///modules/EveryWindow.sys.mjs"
+);
+
+async function windowInited(aId, aWin) {
+  // TestUtils.topicObserved returns [subject, data]. We return the
+  // subject, which in this case is the window.
+  return (
+    await TestUtils.topicObserved(`${aId}:init`, win => {
+      return aWin ? win == aWin : true;
+    })
+  )[0];
+}
+
+function windowUninited(aId, aWin, aClosing) {
+  return TestUtils.topicObserved(`${aId}:uninit`, (win, closing) => {
+    if (aWin && aWin != win) {
+      return false;
+    }
+    if (!aWin) {
+      return true;
+    }
+    if (!!aClosing != !!closing) {
+      return false;
+    }
+    return true;
+  });
+}
+
+function registerEWCallback(id) {
+  EveryWindow.registerCallback(
+    id,
+    win => {
+      Services.obs.notifyObservers(win, `${id}:init`);
+    },
+    (win, closing) => {
+      Services.obs.notifyObservers(win, `${id}:uninit`, closing);
+    }
+  );
+}
+
+function unregisterEWCallback(id, aCallUninit) {
+  EveryWindow.unregisterCallback(id, aCallUninit);
+}
+
+add_task(async function test_stuff() {
+  let win2 = await BrowserTestUtils.openNewBrowserWindow();
+  let win3 = await BrowserTestUtils.openNewBrowserWindow();
+
+  let callbackId1 = "EveryWindow:test:1";
+  let callbackId2 = "EveryWindow:test:2";
+
+  let initPromise = Promise.all([
+    windowInited(callbackId1, window),
+    windowInited(callbackId1, win2),
+    windowInited(callbackId1, win3),
+    windowInited(callbackId2, window),
+    windowInited(callbackId2, win2),
+    windowInited(callbackId2, win3),
+  ]);
+
+  registerEWCallback(callbackId1);
+  registerEWCallback(callbackId2);
+
+  await initPromise;
+  ok(true, "Init called for all existing windows for all registered consumers");
+
+  let uninitPromise = Promise.all([
+    windowUninited(callbackId1, window, false),
+    windowUninited(callbackId1, win2, false),
+    windowUninited(callbackId1, win3, false),
+    windowUninited(callbackId2, window, false),
+    windowUninited(callbackId2, win2, false),
+    windowUninited(callbackId2, win3, false),
+  ]);
+
+  unregisterEWCallback(callbackId1);
+  unregisterEWCallback(callbackId2);
+  await uninitPromise;
+  ok(true, "Uninit called for all existing windows");
+
+  initPromise = Promise.all([
+    windowInited(callbackId1, window),
+    windowInited(callbackId1, win2),
+    windowInited(callbackId1, win3),
+    windowInited(callbackId2, window),
+    windowInited(callbackId2, win2),
+    windowInited(callbackId2, win3),
+  ]);
+
+  registerEWCallback(callbackId1);
+  registerEWCallback(callbackId2);
+
+  await initPromise;
+  ok(true, "Init called for all existing windows for all registered consumers");
+
+  uninitPromise = Promise.all([
+    windowUninited(callbackId1, win2, true),
+    windowUninited(callbackId2, win2, true),
+  ]);
+  await BrowserTestUtils.closeWindow(win2);
+  await uninitPromise;
+  ok(
+    true,
+    "Uninit called with closing=true for win2 for all registered consumers"
+  );
+
+  uninitPromise = Promise.all([
+    windowUninited(callbackId1, win3, true),
+    windowUninited(callbackId2, win3, true),
+  ]);
+  await BrowserTestUtils.closeWindow(win3);
+  await uninitPromise;
+  ok(
+    true,
+    "Uninit called with closing=true for win3 for all registered consumers"
+  );
+
+  initPromise = windowInited(callbackId1);
+  let initPromise2 = windowInited(callbackId2);
+  win2 = await BrowserTestUtils.openNewBrowserWindow();
+  is(await initPromise, win2, "Init called for new window for callback 1");
+  is(await initPromise2, win2, "Init called for new window for callback 2");
+
+  uninitPromise = Promise.all([
+    windowUninited(callbackId1, win2, true),
+    windowUninited(callbackId2, win2, true),
+  ]);
+  await BrowserTestUtils.closeWindow(win2);
+  await uninitPromise;
+  ok(
+    true,
+    "Uninit called with closing=true for win2 for all registered consumers"
+  );
+
+  uninitPromise = windowUninited(callbackId1, window, false);
+  unregisterEWCallback(callbackId1);
+  await uninitPromise;
+  ok(
+    true,
+    "Uninit called for main window without closing flag for the unregistered consumer"
+  );
+
+  uninitPromise = windowUninited(callbackId2, window, false);
+  let timeoutPromise = new Promise(resolve => setTimeout(resolve, 500));
+  unregisterEWCallback(callbackId2, false);
+  let result = await Promise.race([uninitPromise, timeoutPromise]);
+  is(
+    result,
+    undefined,
+    "Uninit not called when unregistering a consumer with aCallUninit=false"
+  );
+});
diff --git a/browser/modules/test/browser/browser_HomePage_add_button.js b/browser/modules/test/browser/browser_HomePage_add_button.js
new file mode 100644
index 0000000000..c185b45a6b
--- /dev/null
+++ b/browser/modules/test/browser/browser_HomePage_add_button.js
@@ -0,0 +1,157 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  HomePage: "resource:///modules/HomePage.sys.mjs",
+});
+
+const kPrefHomePage = "browser.startup.homepage";
+const kPrefExtensionControlled =
+  "browser.startup.homepage_override.extensionControlled";
+const kPrefHomeButtonRemoved = "browser.engagement.home-button.has-removed";
+const kHomeButtonId = "home-button";
+const kUrlbarWidgetId = "urlbar-container";
+
+// eslint-disable-next-line no-empty-pattern
+async function withTestSetup({} = {}, testFn) {
+  CustomizableUI.removeWidgetFromArea(kHomeButtonId);
+
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      [kPrefHomeButtonRemoved, false],
+      [kPrefHomePage, "about:home"],
+      [kPrefExtensionControlled, false],
+    ],
+  });
+
+  HomePage._addCustomizableUiListener();
+
+  try {
+    await testFn();
+  } finally {
+    await SpecialPowers.popPrefEnv();
+    await CustomizableUI.reset();
+  }
+}
+
+function assertHomeButtonInArea(area) {
+  let placement = CustomizableUI.getPlacementOfWidget(kHomeButtonId);
+  is(placement.area, area, "home button in area");
+}
+
+function assertHomeButtonNotPlaced() {
+  ok(
+    !CustomizableUI.getPlacementOfWidget(kHomeButtonId),
+    "home button not placed"
+  );
+}
+
+function assertHasRemovedPref(val) {
+  is(
+    Services.prefs.getBoolPref(kPrefHomeButtonRemoved),
+    val,
+    "Expected removed pref value"
+  );
+}
+
+async function runAddButtonTest() {
+  await withTestSetup({}, async () => {
+    // Setting the homepage once should add to the toolbar.
+    assertHasRemovedPref(false);
+    assertHomeButtonNotPlaced();
+
+    await HomePage.set("https://example.com/");
+
+    assertHomeButtonInArea("nav-bar");
+    assertHasRemovedPref(false);
+
+    // After removing the home button, a new homepage shouldn't add it.
+    CustomizableUI.removeWidgetFromArea(kHomeButtonId);
+
+    await HomePage.set("https://mozilla.org/");
+    assertHomeButtonNotPlaced();
+  });
+}
+
+add_task(async function testAddHomeButtonOnSet() {
+  await runAddButtonTest();
+});
+
+add_task(async function testHomeButtonDoesNotMove() {
+  await withTestSetup({}, async () => {
+    // Setting the homepage should not move the home button.
+    CustomizableUI.addWidgetToArea(kHomeButtonId, "TabsToolbar");
+    assertHasRemovedPref(false);
+    assertHomeButtonInArea("TabsToolbar");
+
+    await HomePage.set("https://example.com/");
+
+    assertHasRemovedPref(false);
+    assertHomeButtonInArea("TabsToolbar");
+  });
+});
+
+add_task(async function testHomeButtonNotAddedBlank() {
+  await withTestSetup({}, async () => {
+    assertHomeButtonNotPlaced();
+    assertHasRemovedPref(false);
+
+    await HomePage.set("about:blank");
+
+    assertHasRemovedPref(false);
+    assertHomeButtonNotPlaced();
+
+    await HomePage.set("about:home");
+
+    assertHasRemovedPref(false);
+    assertHomeButtonNotPlaced();
+  });
+});
+
+add_task(async function testHomeButtonNotAddedExtensionControlled() {
+  await withTestSetup({}, async () => {
+    assertHomeButtonNotPlaced();
+    assertHasRemovedPref(false);
+    Services.prefs.setBoolPref(kPrefExtensionControlled, true);
+
+    await HomePage.set("https://search.example.com/?q=%s");
+
+    assertHomeButtonNotPlaced();
+  });
+});
+
+add_task(async function testHomeButtonPlacement() {
+  await withTestSetup({}, async () => {
+    assertHomeButtonNotPlaced();
+    HomePage._maybeAddHomeButtonToToolbar("https://example.com");
+    let homePlacement = CustomizableUI.getPlacementOfWidget(kHomeButtonId);
+    is(homePlacement.area, "nav-bar", "Home button is in the nav-bar");
+    is(homePlacement.position, 3, "Home button is after stop/refresh");
+
+    let addressBarPlacement =
+      CustomizableUI.getPlacementOfWidget(kUrlbarWidgetId);
+    is(
+      addressBarPlacement.position,
+      5,
+      "There's a space between home and urlbar"
+    );
+    CustomizableUI.removeWidgetFromArea(kHomeButtonId);
+    Services.prefs.setBoolPref(kPrefHomeButtonRemoved, false);
+
+    try {
+      CustomizableUI.addWidgetToArea(kUrlbarWidgetId, "nav-bar", 1);
+      HomePage._maybeAddHomeButtonToToolbar("https://example.com");
+      homePlacement = CustomizableUI.getPlacementOfWidget(kHomeButtonId);
+      is(homePlacement.area, "nav-bar", "Home button is in the nav-bar");
+      is(homePlacement.position, 1, "Home button is right before the urlbar");
+    } finally {
+      CustomizableUI.addWidgetToArea(
+        kUrlbarWidgetId,
+        addressBarPlacement.area,
+        addressBarPlacement.position
+      );
+    }
+  });
+});
diff --git a/browser/modules/test/browser/browser_PageActions.js b/browser/modules/test/browser/browser_PageActions.js
new file mode 100644
index 0000000000..4f86962a01
--- /dev/null
+++ b/browser/modules/test/browser/browser_PageActions.js
@@ -0,0 +1,1402 @@
+"use strict";
+
+// This is a test for PageActions.sys.mjs, specifically the generalized parts that
+// add and remove page actions and toggle them in the urlbar.  This does not
+// test the built-in page actions; browser_page_action_menu.js does that.
+
+// Initialization.  Must run first.
+add_setup(async function () {
+  // The page action urlbar button, and therefore the panel, is only shown when
+  // the current tab is actionable -- i.e., a normal web page.  about:blank is
+  // not, so open a new tab first thing, and close it when this test is done.
+  let tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    url: "http://example.com/",
+  });
+  registerCleanupFunction(async () => {
+    BrowserTestUtils.removeTab(tab);
+  });
+
+  await initPageActionsTest();
+});
+
+// Tests a simple non-built-in action without an iframe or subview.  Also
+// thoroughly checks most of the action's properties, methods, and DOM nodes, so
+// it's not necessary to do that in general in other test tasks.
+add_task(async function simple() {
+  let iconURL = "chrome://browser/skin/mail.svg";
+  let id = "test-simple";
+  let title = "Test simple";
+  let tooltip = "Test simple tooltip";
+
+  let onCommandCallCount = 0;
+  let onPlacedInPanelCallCount = 0;
+  let onPlacedInUrlbarCallCount = 0;
+  let onShowingInPanelCallCount = 0;
+  let onCommandExpectedButtonID;
+
+  let panelButtonID = BrowserPageActions.panelButtonNodeIDForActionID(id);
+  let urlbarButtonID = BrowserPageActions.urlbarButtonNodeIDForActionID(id);
+
+  // Open the panel so that actions are added to it, and then close it.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  let initialActions = PageActions.actions;
+  let initialActionsInPanel = PageActions.actionsInPanel(window);
+  let initialActionsInUrlbar = PageActions.actionsInUrlbar(window);
+
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      iconURL,
+      id,
+      title,
+      tooltip,
+      onCommand(event, buttonNode) {
+        onCommandCallCount++;
+        Assert.ok(event, "event should be non-null: " + event);
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, onCommandExpectedButtonID, "buttonNode.id");
+      },
+      onPlacedInPanel(buttonNode) {
+        onPlacedInPanelCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, panelButtonID, "buttonNode.id");
+      },
+      onPlacedInUrlbar(buttonNode) {
+        onPlacedInUrlbarCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, urlbarButtonID, "buttonNode.id");
+      },
+      onShowingInPanel(buttonNode) {
+        onShowingInPanelCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, panelButtonID, "buttonNode.id");
+      },
+    })
+  );
+
+  Assert.equal(action.getIconURL(), iconURL, "iconURL");
+  Assert.equal(action.id, id, "id");
+  Assert.equal(action.pinnedToUrlbar, true, "pinnedToUrlbar");
+  Assert.equal(action.getDisabled(), false, "disabled");
+  Assert.equal(action.getDisabled(window), false, "disabled in window");
+  Assert.equal(action.getTitle(), title, "title");
+  Assert.equal(action.getTitle(window), title, "title in window");
+  Assert.equal(action.getTooltip(), tooltip, "tooltip");
+  Assert.equal(action.getTooltip(window), tooltip, "tooltip in window");
+  Assert.equal(action.getWantsSubview(), false, "subview");
+  Assert.equal(action.getWantsSubview(window), false, "subview in window");
+  Assert.equal(action.urlbarIDOverride, null, "urlbarIDOverride");
+  Assert.equal(action.wantsIframe, false, "wantsIframe");
+
+  Assert.ok(!("__insertBeforeActionID" in action), "__insertBeforeActionID");
+  Assert.ok(!("__isSeparator" in action), "__isSeparator");
+  Assert.ok(!("__urlbarNodeInMarkup" in action), "__urlbarNodeInMarkup");
+  Assert.ok(!("__transient" in action), "__transient");
+
+  // The action shouldn't be placed in the panel until it opens for the first
+  // time.
+  Assert.equal(
+    onPlacedInPanelCallCount,
+    0,
+    "onPlacedInPanelCallCount should remain 0"
+  );
+  Assert.equal(
+    onPlacedInUrlbarCallCount,
+    1,
+    "onPlacedInUrlbarCallCount after adding the action"
+  );
+  Assert.equal(
+    onShowingInPanelCallCount,
+    0,
+    "onShowingInPanelCallCount should remain 0"
+  );
+
+  // Open the panel so that actions are added to it, and then close it.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  Assert.equal(
+    onPlacedInPanelCallCount,
+    1,
+    "onPlacedInPanelCallCount should be inc'ed"
+  );
+  Assert.equal(
+    onShowingInPanelCallCount,
+    1,
+    "onShowingInPanelCallCount should be inc'ed"
+  );
+
+  // Build an array of the expected actions in the panel and compare it to the
+  // actual actions.  Don't assume that there are or aren't already other non-
+  // built-in actions.
+  let sepIndex = initialActionsInPanel.findIndex(
+    a => a.id == PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+  );
+  let initialSepIndex = sepIndex;
+  let indexInPanel;
+  if (sepIndex < 0) {
+    // No prior non-built-in actions.
+    indexInPanel = initialActionsInPanel.length;
+  } else {
+    // Prior non-built-in actions.  Find the index where the action goes.
+    for (
+      indexInPanel = sepIndex + 1;
+      indexInPanel < initialActionsInPanel.length;
+      indexInPanel++
+    ) {
+      let a = initialActionsInPanel[indexInPanel];
+      if (a.getTitle().localeCompare(action.getTitle()) < 1) {
+        break;
+      }
+    }
+  }
+  let expectedActionsInPanel = initialActionsInPanel.slice();
+  expectedActionsInPanel.splice(indexInPanel, 0, action);
+  // The separator between the built-ins and non-built-ins should be present
+  // if it's not already.
+  if (sepIndex < 0) {
+    expectedActionsInPanel.splice(
+      indexInPanel,
+      0,
+      new PageActions.Action({
+        id: PageActions.ACTION_ID_BUILT_IN_SEPARATOR,
+        _isSeparator: true,
+      })
+    );
+    sepIndex = indexInPanel;
+    indexInPanel++;
+  }
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window),
+    expectedActionsInPanel,
+    "Actions in panel after adding the action"
+  );
+
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window),
+    [action].concat(initialActionsInUrlbar),
+    "Actions in urlbar after adding the action"
+  );
+
+  // Check the set of all actions.
+  Assert.deepEqual(
+    new Set(PageActions.actions),
+    new Set(initialActions.concat([action])),
+    "All actions after adding the action"
+  );
+
+  Assert.deepEqual(
+    PageActions.actionForID(action.id),
+    action,
+    "actionForID should be action"
+  );
+
+  Assert.ok(
+    PageActions._persistedActions.ids.includes(action.id),
+    "PageActions should record action in its list of seen actions"
+  );
+
+  // The action's panel button should have been created.
+  let panelButtonNode =
+    BrowserPageActions.mainViewBodyNode.children[indexInPanel];
+  Assert.notEqual(panelButtonNode, null, "panelButtonNode");
+  Assert.equal(panelButtonNode.id, panelButtonID, "panelButtonID");
+  Assert.equal(
+    panelButtonNode.getAttribute("label"),
+    action.getTitle(),
+    "label"
+  );
+
+  // The separator between the built-ins and non-built-ins should exist.
+  let sepNode = BrowserPageActions.mainViewBodyNode.children[sepIndex];
+  Assert.notEqual(sepNode, null, "sepNode");
+  Assert.equal(
+    sepNode.id,
+    BrowserPageActions.panelButtonNodeIDForActionID(
+      PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+    ),
+    "sepNode.id"
+  );
+
+  let urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.equal(!!urlbarButtonNode, true, "urlbarButtonNode");
+
+  // Open the panel, click the action's button.
+  await promiseOpenPageActionPanel();
+  Assert.equal(
+    onShowingInPanelCallCount,
+    2,
+    "onShowingInPanelCallCount should be inc'ed"
+  );
+  onCommandExpectedButtonID = panelButtonID;
+  EventUtils.synthesizeMouseAtCenter(panelButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.equal(onCommandCallCount, 1, "onCommandCallCount should be inc'ed");
+
+  // Show the action's button in the urlbar.
+  action.pinnedToUrlbar = true;
+  Assert.equal(
+    onPlacedInUrlbarCallCount,
+    1,
+    "onPlacedInUrlbarCallCount should be inc'ed"
+  );
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.notEqual(urlbarButtonNode, null, "urlbarButtonNode");
+
+  // The button should have been inserted before the bookmark star.
+  Assert.notEqual(
+    urlbarButtonNode.nextElementSibling,
+    null,
+    "Should be a next node"
+  );
+  Assert.equal(
+    urlbarButtonNode.nextElementSibling.id,
+    PageActions.actionForID(PageActions.ACTION_ID_BOOKMARK).urlbarIDOverride,
+    "Next node should be the bookmark star"
+  );
+
+  // Disable the action.  The button in the urlbar should be removed, and the
+  // button in the panel should be disabled.
+  action.setDisabled(true);
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.equal(urlbarButtonNode, null, "urlbar button should be removed");
+  Assert.equal(
+    panelButtonNode.disabled,
+    true,
+    "panel button should be disabled"
+  );
+
+  // Enable the action.  The button in the urlbar should be added back, and the
+  // button in the panel should be enabled.
+  action.setDisabled(false);
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.notEqual(urlbarButtonNode, null, "urlbar button should be added back");
+  Assert.equal(
+    panelButtonNode.disabled,
+    false,
+    "panel button should not be disabled"
+  );
+
+  // Click the urlbar button.
+  onCommandExpectedButtonID = urlbarButtonID;
+  EventUtils.synthesizeMouseAtCenter(urlbarButtonNode, {});
+  Assert.equal(onCommandCallCount, 2, "onCommandCallCount should be inc'ed");
+
+  // Set a new title.
+  let newTitle = title + " new title";
+  action.setTitle(newTitle);
+  Assert.equal(action.getTitle(), newTitle, "New title");
+  Assert.equal(
+    panelButtonNode.getAttribute("label"),
+    action.getTitle(),
+    "New label"
+  );
+
+  // Now that pinnedToUrlbar has been toggled, make sure that it sticks across
+  // app restarts.  Simulate that by "unregistering" the action (not by removing
+  // it, which is more permanent) and then registering it again.
+
+  // unregister
+  PageActions._actionsByID.delete(action.id);
+  let index = PageActions._nonBuiltInActions.findIndex(a => a.id == action.id);
+  Assert.ok(index >= 0, "Action should be in _nonBuiltInActions to begin with");
+  PageActions._nonBuiltInActions.splice(index, 1);
+
+  // register again
+  PageActions._registerAction(action);
+
+  // check relevant properties
+  Assert.ok(
+    PageActions._persistedActions.ids.includes(action.id),
+    "PageActions should have 'seen' the action"
+  );
+  Assert.ok(
+    PageActions._persistedActions.idsInUrlbar.includes(action.id),
+    "idsInUrlbar should still include the action"
+  );
+  Assert.ok(action.pinnedToUrlbar, "pinnedToUrlbar should still be true");
+  Assert.ok(
+    action._pinnedToUrlbar,
+    "_pinnedToUrlbar should still be true, for good measure"
+  );
+
+  // Remove the action.
+  action.remove();
+  panelButtonNode = document.getElementById(panelButtonID);
+  Assert.equal(panelButtonNode, null, "panelButtonNode");
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.equal(urlbarButtonNode, null, "urlbarButtonNode");
+
+  let separatorNode = document.getElementById(
+    BrowserPageActions.panelButtonNodeIDForActionID(
+      PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+    )
+  );
+  if (initialSepIndex < 0) {
+    // The separator between the built-in actions and non-built-in actions
+    // should be gone now, too.
+    Assert.equal(separatorNode, null, "No separator");
+    Assert.ok(
+      !BrowserPageActions.mainViewBodyNode.lastElementChild.localName.includes(
+        "separator"
+      ),
+      "Last child should not be separator"
+    );
+  } else {
+    // The separator should still be present.
+    Assert.notEqual(separatorNode, null, "Separator should still exist");
+  }
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window),
+    initialActionsInPanel,
+    "Actions in panel should go back to initial"
+  );
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window),
+    initialActionsInUrlbar,
+    "Actions in urlbar should go back to initial"
+  );
+  Assert.deepEqual(
+    PageActions.actions,
+    initialActions,
+    "Actions should go back to initial"
+  );
+  Assert.equal(
+    PageActions.actionForID(action.id),
+    null,
+    "actionForID should be null"
+  );
+
+  Assert.ok(
+    PageActions._persistedActions.ids.includes(action.id),
+    "Action ID should remain in cache until purged"
+  );
+  PageActions._purgeUnregisteredPersistedActions();
+  Assert.ok(
+    !PageActions._persistedActions.ids.includes(action.id),
+    "Action ID should be removed from cache after being purged"
+  );
+});
+
+// Tests a non-built-in action with a subview.
+add_task(async function withSubview() {
+  let id = "test-subview";
+
+  let onActionPlacedInPanelCallCount = 0;
+  let onActionPlacedInUrlbarCallCount = 0;
+  let onSubviewPlacedCount = 0;
+  let onSubviewShowingCount = 0;
+
+  let panelButtonID = BrowserPageActions.panelButtonNodeIDForActionID(id);
+  let urlbarButtonID = BrowserPageActions.urlbarButtonNodeIDForActionID(id);
+
+  let panelViewIDPanel = BrowserPageActions._panelViewNodeIDForActionID(
+    id,
+    false
+  );
+  let panelViewIDUrlbar = BrowserPageActions._panelViewNodeIDForActionID(
+    id,
+    true
+  );
+
+  let onSubviewPlacedExpectedPanelViewID = panelViewIDPanel;
+  let onSubviewShowingExpectedPanelViewID;
+
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      iconURL: "chrome://browser/skin/mail.svg",
+      id,
+      pinnedToUrlbar: true,
+      title: "Test subview",
+      wantsSubview: true,
+      onPlacedInPanel(buttonNode) {
+        onActionPlacedInPanelCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, panelButtonID, "buttonNode.id");
+      },
+      onPlacedInUrlbar(buttonNode) {
+        onActionPlacedInUrlbarCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, urlbarButtonID, "buttonNode.id");
+      },
+      onSubviewPlaced(panelViewNode) {
+        onSubviewPlacedCount++;
+        Assert.ok(
+          panelViewNode,
+          "panelViewNode should be non-null: " + panelViewNode
+        );
+        Assert.equal(
+          panelViewNode.id,
+          onSubviewPlacedExpectedPanelViewID,
+          "panelViewNode.id"
+        );
+      },
+      onSubviewShowing(panelViewNode) {
+        onSubviewShowingCount++;
+        Assert.ok(
+          panelViewNode,
+          "panelViewNode should be non-null: " + panelViewNode
+        );
+        Assert.equal(
+          panelViewNode.id,
+          onSubviewShowingExpectedPanelViewID,
+          "panelViewNode.id"
+        );
+      },
+    })
+  );
+
+  Assert.equal(action.id, id, "id");
+  Assert.equal(action.getWantsSubview(), true, "subview");
+  Assert.equal(action.getWantsSubview(window), true, "subview in window");
+
+  // The action shouldn't be placed in the panel until it opens for the first
+  // time.
+  Assert.equal(
+    onActionPlacedInPanelCallCount,
+    0,
+    "onActionPlacedInPanelCallCount should be 0"
+  );
+  Assert.equal(onSubviewPlacedCount, 0, "onSubviewPlacedCount should be 0");
+
+  // But it should be placed in the urlbar.
+  Assert.equal(
+    onActionPlacedInUrlbarCallCount,
+    1,
+    "onActionPlacedInUrlbarCallCount should be 0"
+  );
+
+  // Open the panel, which should place the action in it.
+  await promiseOpenPageActionPanel();
+
+  Assert.equal(
+    onActionPlacedInPanelCallCount,
+    1,
+    "onActionPlacedInPanelCallCount should be inc'ed"
+  );
+  Assert.equal(
+    onSubviewPlacedCount,
+    1,
+    "onSubviewPlacedCount should be inc'ed"
+  );
+  Assert.equal(
+    onSubviewShowingCount,
+    0,
+    "onSubviewShowingCount should remain 0"
+  );
+
+  // The action's panel button and view (in the main page action panel) should
+  // have been created.
+  let panelButtonNode = document.getElementById(panelButtonID);
+  Assert.notEqual(panelButtonNode, null, "panelButtonNode");
+
+  // The action's urlbar button should have been created.
+  let urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.notEqual(urlbarButtonNode, null, "urlbarButtonNode");
+
+  // The button should have been inserted before the bookmark star.
+  Assert.notEqual(
+    urlbarButtonNode.nextElementSibling,
+    null,
+    "Should be a next node"
+  );
+  Assert.equal(
+    urlbarButtonNode.nextElementSibling.id,
+    PageActions.actionForID(PageActions.ACTION_ID_BOOKMARK).urlbarIDOverride,
+    "Next node should be the bookmark star"
+  );
+
+  // Click the action's button in the panel.  The subview should be shown.
+  Assert.equal(
+    onSubviewShowingCount,
+    0,
+    "onSubviewShowingCount should remain 0"
+  );
+  let subviewShownPromise = promisePageActionViewShown();
+  onSubviewShowingExpectedPanelViewID = panelViewIDPanel;
+  panelButtonNode.click();
+  await subviewShownPromise;
+
+  // Click the main button to hide the main panel.
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  // Click the action's urlbar button, which should open the activated-action
+  // panel showing the subview.
+  onSubviewPlacedExpectedPanelViewID = panelViewIDUrlbar;
+  onSubviewShowingExpectedPanelViewID = panelViewIDUrlbar;
+  EventUtils.synthesizeMouseAtCenter(urlbarButtonNode, {});
+  await promisePanelShown(BrowserPageActions._activatedActionPanelID);
+  Assert.equal(
+    onSubviewPlacedCount,
+    2,
+    "onSubviewPlacedCount should be inc'ed"
+  );
+  Assert.equal(
+    onSubviewShowingCount,
+    2,
+    "onSubviewShowingCount should be inc'ed"
+  );
+
+  // Click the urlbar button again.  The activated-action panel should close.
+  EventUtils.synthesizeMouseAtCenter(urlbarButtonNode, {});
+  assertActivatedPageActionPanelHidden();
+
+  // Remove the action.
+  action.remove();
+  panelButtonNode = document.getElementById(panelButtonID);
+  Assert.equal(panelButtonNode, null, "panelButtonNode");
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.equal(urlbarButtonNode, null, "urlbarButtonNode");
+  let panelViewNodePanel = document.getElementById(panelViewIDPanel);
+  Assert.equal(panelViewNodePanel, null, "panelViewNodePanel");
+  let panelViewNodeUrlbar = document.getElementById(panelViewIDUrlbar);
+  Assert.equal(panelViewNodeUrlbar, null, "panelViewNodeUrlbar");
+});
+
+// Tests a non-built-in action with an iframe.
+add_task(async function withIframe() {
+  let id = "test-iframe";
+
+  let onCommandCallCount = 0;
+  let onPlacedInPanelCallCount = 0;
+  let onPlacedInUrlbarCallCount = 0;
+  let onIframeShowingCount = 0;
+
+  let panelButtonID = BrowserPageActions.panelButtonNodeIDForActionID(id);
+  let urlbarButtonID = BrowserPageActions.urlbarButtonNodeIDForActionID(id);
+
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      iconURL: "chrome://browser/skin/mail.svg",
+      id,
+      pinnedToUrlbar: true,
+      title: "Test iframe",
+      wantsIframe: true,
+      onCommand(event, buttonNode) {
+        onCommandCallCount++;
+      },
+      onIframeShowing(iframeNode, panelNode) {
+        onIframeShowingCount++;
+        Assert.ok(iframeNode, "iframeNode should be non-null: " + iframeNode);
+        Assert.equal(iframeNode.localName, "iframe", "iframe localName");
+        Assert.ok(panelNode, "panelNode should be non-null: " + panelNode);
+        Assert.equal(
+          panelNode.id,
+          BrowserPageActions._activatedActionPanelID,
+          "panelNode.id"
+        );
+      },
+      onPlacedInPanel(buttonNode) {
+        onPlacedInPanelCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, panelButtonID, "buttonNode.id");
+      },
+      onPlacedInUrlbar(buttonNode) {
+        onPlacedInUrlbarCallCount++;
+        Assert.ok(buttonNode, "buttonNode should be non-null: " + buttonNode);
+        Assert.equal(buttonNode.id, urlbarButtonID, "buttonNode.id");
+      },
+    })
+  );
+
+  Assert.equal(action.id, id, "id");
+  Assert.equal(action.wantsIframe, true, "wantsIframe");
+
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  Assert.equal(
+    onPlacedInPanelCallCount,
+    1,
+    "onPlacedInPanelCallCount should be inc'ed"
+  );
+  Assert.equal(
+    onPlacedInUrlbarCallCount,
+    1,
+    "onPlacedInUrlbarCallCount should be inc'ed"
+  );
+  Assert.equal(onIframeShowingCount, 0, "onIframeShowingCount should remain 0");
+  Assert.equal(onCommandCallCount, 0, "onCommandCallCount should remain 0");
+
+  // The action's panel button should have been created.
+  let panelButtonNode = document.getElementById(panelButtonID);
+  Assert.notEqual(panelButtonNode, null, "panelButtonNode");
+
+  // The action's urlbar button should have been created.
+  let urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.notEqual(urlbarButtonNode, null, "urlbarButtonNode");
+
+  // The button should have been inserted before the bookmark star.
+  Assert.notEqual(
+    urlbarButtonNode.nextElementSibling,
+    null,
+    "Should be a next node"
+  );
+  Assert.equal(
+    urlbarButtonNode.nextElementSibling.id,
+    PageActions.actionForID(PageActions.ACTION_ID_BOOKMARK).urlbarIDOverride,
+    "Next node should be the bookmark star"
+  );
+
+  // Open the panel, click the action's button.
+  await promiseOpenPageActionPanel();
+  Assert.equal(onIframeShowingCount, 0, "onIframeShowingCount should remain 0");
+  EventUtils.synthesizeMouseAtCenter(panelButtonNode, {});
+  await promisePanelShown(BrowserPageActions._activatedActionPanelID);
+  Assert.equal(onCommandCallCount, 1, "onCommandCallCount should be inc'ed");
+  Assert.equal(
+    onIframeShowingCount,
+    1,
+    "onIframeShowingCount should be inc'ed"
+  );
+
+  // The activated-action panel should have opened, anchored to the action's
+  // urlbar button.
+  let aaPanel = document.getElementById(
+    BrowserPageActions._activatedActionPanelID
+  );
+  Assert.notEqual(aaPanel, null, "activated-action panel");
+  Assert.equal(aaPanel.anchorNode.id, urlbarButtonID, "aaPanel.anchorNode.id");
+  EventUtils.synthesizeMouseAtCenter(urlbarButtonNode, {});
+  assertActivatedPageActionPanelHidden();
+
+  // Click the action's urlbar button.
+  EventUtils.synthesizeMouseAtCenter(urlbarButtonNode, {});
+  await promisePanelShown(BrowserPageActions._activatedActionPanelID);
+  Assert.equal(onCommandCallCount, 2, "onCommandCallCount should be inc'ed");
+  Assert.equal(
+    onIframeShowingCount,
+    2,
+    "onIframeShowingCount should be inc'ed"
+  );
+
+  // The activated-action panel should have opened, again anchored to the
+  // action's urlbar button.
+  aaPanel = document.getElementById(BrowserPageActions._activatedActionPanelID);
+  Assert.notEqual(aaPanel, null, "aaPanel");
+  Assert.equal(aaPanel.anchorNode.id, urlbarButtonID, "aaPanel.anchorNode.id");
+  EventUtils.synthesizeMouseAtCenter(urlbarButtonNode, {});
+  assertActivatedPageActionPanelHidden();
+
+  // Hide the action's button in the urlbar.
+  action.pinnedToUrlbar = false;
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.equal(urlbarButtonNode, null, "urlbarButtonNode");
+
+  // Open the panel, click the action's button.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(panelButtonNode, {});
+  await promisePanelShown(BrowserPageActions._activatedActionPanelID);
+  Assert.equal(onCommandCallCount, 3, "onCommandCallCount should be inc'ed");
+  Assert.equal(
+    onIframeShowingCount,
+    3,
+    "onIframeShowingCount should be inc'ed"
+  );
+
+  // The activated-action panel should have opened, this time anchored to the
+  // main page action button in the urlbar.
+  aaPanel = document.getElementById(BrowserPageActions._activatedActionPanelID);
+  Assert.notEqual(aaPanel, null, "aaPanel");
+  Assert.equal(
+    aaPanel.anchorNode.id,
+    BrowserPageActions.mainButtonNode.id,
+    "aaPanel.anchorNode.id"
+  );
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  assertActivatedPageActionPanelHidden();
+
+  // Remove the action.
+  action.remove();
+  panelButtonNode = document.getElementById(panelButtonID);
+  Assert.equal(panelButtonNode, null, "panelButtonNode");
+  urlbarButtonNode = document.getElementById(urlbarButtonID);
+  Assert.equal(urlbarButtonNode, null, "urlbarButtonNode");
+});
+
+// Tests an action with the _insertBeforeActionID option set.
+add_task(async function insertBeforeActionID() {
+  let id = "test-insertBeforeActionID";
+  let panelButtonID = BrowserPageActions.panelButtonNodeIDForActionID(id);
+
+  let initialActions = PageActions.actionsInPanel(window);
+  let initialBuiltInActions = PageActions._builtInActions.slice();
+  let initialNonBuiltInActions = PageActions._nonBuiltInActions.slice();
+
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      id,
+      title: "Test insertBeforeActionID",
+      _insertBeforeActionID: PageActions.ACTION_ID_BOOKMARK_SEPARATOR,
+    })
+  );
+
+  Assert.equal(action.id, id, "id");
+  Assert.ok("__insertBeforeActionID" in action, "__insertBeforeActionID");
+  Assert.equal(
+    action.__insertBeforeActionID,
+    PageActions.ACTION_ID_BOOKMARK_SEPARATOR,
+    "action.__insertBeforeActionID"
+  );
+
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  let newActions = PageActions.actionsInPanel(window);
+  Assert.equal(
+    newActions.length,
+    initialActions.length + 1,
+    "PageActions.actions.length should be updated"
+  );
+  Assert.equal(
+    PageActions._builtInActions.length,
+    initialBuiltInActions.length + 1,
+    "PageActions._builtInActions.length should be updated"
+  );
+  Assert.equal(
+    PageActions._nonBuiltInActions.length,
+    initialNonBuiltInActions.length,
+    "PageActions._nonBuiltInActions.length should remain the same"
+  );
+
+  // The action's panel button should have been created.
+  let panelButtonNode = document.getElementById(panelButtonID);
+  Assert.notEqual(panelButtonNode, null, "panelButtonNode");
+
+  // The separator between the built-in and non-built-in actions should not have
+  // been created.
+  Assert.equal(
+    document.getElementById(
+      BrowserPageActions.panelButtonNodeIDForActionID(
+        PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+      )
+    ),
+    null,
+    "Separator should be gone"
+  );
+
+  action.remove();
+});
+
+// Tests that the ordering in the panel of multiple non-built-in actions is
+// alphabetical.
+add_task(async function multipleNonBuiltInOrdering() {
+  let idPrefix = "test-multipleNonBuiltInOrdering-";
+  let titlePrefix = "Test multipleNonBuiltInOrdering ";
+
+  let initialActions = PageActions.actionsInPanel(window);
+  let initialBuiltInActions = PageActions._builtInActions.slice();
+  let initialNonBuiltInActions = PageActions._nonBuiltInActions.slice();
+
+  // Create some actions in an out-of-order order.
+  let actions = [2, 1, 4, 3].map(index => {
+    return PageActions.addAction(
+      new PageActions.Action({
+        id: idPrefix + index,
+        title: titlePrefix + index,
+      })
+    );
+  });
+
+  // + 1 for the separator between built-in and non-built-in actions.
+  Assert.equal(
+    PageActions.actionsInPanel(window).length,
+    initialActions.length + actions.length + 1,
+    "PageActions.actionsInPanel().length should be updated"
+  );
+
+  Assert.equal(
+    PageActions._builtInActions.length,
+    initialBuiltInActions.length,
+    "PageActions._builtInActions.length should be same"
+  );
+  Assert.equal(
+    PageActions._nonBuiltInActions.length,
+    initialNonBuiltInActions.length + actions.length,
+    "PageActions._nonBuiltInActions.length should be updated"
+  );
+
+  // Look at the final actions.length actions in PageActions.actions, from first
+  // to last.
+  for (let i = 0; i < actions.length; i++) {
+    let expectedIndex = i + 1;
+    let actualAction = PageActions._nonBuiltInActions[i];
+    Assert.equal(
+      actualAction.id,
+      idPrefix + expectedIndex,
+      "actualAction.id for index: " + i
+    );
+  }
+
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  // Check the button nodes in the panel.
+  let expectedIndex = 1;
+  let buttonNode = document.getElementById(
+    BrowserPageActions.panelButtonNodeIDForActionID(idPrefix + expectedIndex)
+  );
+  Assert.notEqual(buttonNode, null, "buttonNode");
+  Assert.notEqual(
+    buttonNode.previousElementSibling,
+    null,
+    "buttonNode.previousElementSibling"
+  );
+  Assert.equal(
+    buttonNode.previousElementSibling.id,
+    BrowserPageActions.panelButtonNodeIDForActionID(
+      PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+    ),
+    "buttonNode.previousElementSibling.id"
+  );
+  for (let i = 0; i < actions.length; i++) {
+    Assert.notEqual(buttonNode, null, "buttonNode at index: " + i);
+    Assert.equal(
+      buttonNode.id,
+      BrowserPageActions.panelButtonNodeIDForActionID(idPrefix + expectedIndex),
+      "buttonNode.id at index: " + i
+    );
+    buttonNode = buttonNode.nextElementSibling;
+    expectedIndex++;
+  }
+  Assert.equal(buttonNode, null, "Nothing should come after the last button");
+
+  for (let action of actions) {
+    action.remove();
+  }
+
+  // The separator between the built-in and non-built-in actions should be gone.
+  Assert.equal(
+    document.getElementById(
+      BrowserPageActions.panelButtonNodeIDForActionID(
+        PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+      )
+    ),
+    null,
+    "Separator should be gone"
+  );
+});
+
+// Makes sure the panel is correctly updated when a non-built-in action is
+// added before the built-in actions; and when all built-in actions are removed
+// and added back.
+add_task(async function nonBuiltFirst() {
+  let initialActions = PageActions.actions;
+  let initialActionsInPanel = PageActions.actionsInPanel(window);
+
+  // Remove all actions.
+  for (let action of initialActions) {
+    action.remove();
+  }
+
+  // Check the actions.
+  Assert.deepEqual(
+    PageActions.actions.map(a => a.id),
+    [],
+    "PageActions.actions should be empty"
+  );
+  Assert.deepEqual(
+    PageActions._builtInActions.map(a => a.id),
+    [],
+    "PageActions._builtInActions should be empty"
+  );
+  Assert.deepEqual(
+    PageActions._nonBuiltInActions.map(a => a.id),
+    [],
+    "PageActions._nonBuiltInActions should be empty"
+  );
+
+  // Check the panel.
+  Assert.equal(
+    BrowserPageActions.mainViewBodyNode.children.length,
+    0,
+    "All nodes should be gone"
+  );
+
+  // Add a non-built-in action.
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      id: "test-nonBuiltFirst",
+      title: "Test nonBuiltFirst",
+    })
+  );
+
+  // Check the actions.
+  Assert.deepEqual(
+    PageActions.actions.map(a => a.id),
+    [action.id],
+    "Action should be in PageActions.actions"
+  );
+  Assert.deepEqual(
+    PageActions._builtInActions.map(a => a.id),
+    [],
+    "PageActions._builtInActions should be empty"
+  );
+  Assert.deepEqual(
+    PageActions._nonBuiltInActions.map(a => a.id),
+    [action.id],
+    "Action should be in PageActions._nonBuiltInActions"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    [BrowserPageActions.panelButtonNodeIDForActionID(action.id)],
+    "Action should be in panel"
+  );
+
+  // Now add back all the actions.
+  for (let a of initialActions) {
+    PageActions.addAction(a);
+  }
+
+  // Check the actions.
+  Assert.deepEqual(
+    new Set(PageActions.actions.map(a => a.id)),
+    new Set(initialActions.map(a => a.id).concat([action.id])),
+    "All actions should be in PageActions.actions"
+  );
+  Assert.deepEqual(
+    PageActions._builtInActions.map(a => a.id),
+    initialActions.filter(a => !a.__transient).map(a => a.id),
+    "PageActions._builtInActions should be initial actions"
+  );
+  Assert.deepEqual(
+    PageActions._nonBuiltInActions.map(a => a.id),
+    [action.id],
+    "PageActions._nonBuiltInActions should contain action"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_BUILT_IN_SEPARATOR], [action.id]),
+    "All actions should be in PageActions.actionsInPanel()"
+  );
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_BUILT_IN_SEPARATOR], [action.id])
+      .map(id => BrowserPageActions.panelButtonNodeIDForActionID(id)),
+    "Panel should contain all actions"
+  );
+
+  // Remove the test action.
+  action.remove();
+
+  // Check the actions.
+  Assert.deepEqual(
+    PageActions.actions.map(a => a.id),
+    initialActions.map(a => a.id),
+    "Action should no longer be in PageActions.actions"
+  );
+  Assert.deepEqual(
+    PageActions._builtInActions.map(a => a.id),
+    initialActions.filter(a => !a.__transient).map(a => a.id),
+    "PageActions._builtInActions should be initial actions"
+  );
+  Assert.deepEqual(
+    PageActions._nonBuiltInActions.map(a => a.id),
+    [],
+    "Action should no longer be in PageActions._nonBuiltInActions"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel.map(a => a.id),
+    "Action should no longer be in PageActions.actionsInPanel()"
+  );
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel.map(a =>
+      BrowserPageActions.panelButtonNodeIDForActionID(a.id)
+    ),
+    "Action should no longer be in panel"
+  );
+});
+
+// Adds an action, changes its placement in the urlbar to something non-default,
+// removes the action, and then adds it back.  Since the action was removed and
+// re-added without restarting the app (or more accurately without calling
+// PageActions._purgeUnregisteredPersistedActions), the action should remain in
+// persisted state and retain its last placement in the urlbar.
+add_task(async function removeRetainState() {
+  // Get the list of actions initially in the urlbar.
+  let initialActionsInUrlbar = PageActions.actionsInUrlbar(window);
+  Assert.ok(
+    !!initialActionsInUrlbar.length,
+    "This test expects there to be at least one action in the urlbar initially (like the bookmark star)"
+  );
+
+  // Add a test action.
+  let id = "test-removeRetainState";
+  let testAction = PageActions.addAction(
+    new PageActions.Action({
+      id,
+      title: "Test removeRetainState",
+    })
+  );
+
+  // Show its button in the urlbar.
+  testAction.pinnedToUrlbar = true;
+
+  // "Move" the test action to the front of the urlbar by toggling
+  // pinnedToUrlbar for all the other actions in the urlbar.
+  for (let action of initialActionsInUrlbar) {
+    action.pinnedToUrlbar = false;
+    action.pinnedToUrlbar = true;
+  }
+
+  // Check the actions in PageActions.actionsInUrlbar.
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window).map(a => a.id),
+    [testAction].concat(initialActionsInUrlbar).map(a => a.id),
+    "PageActions.actionsInUrlbar should be in expected order: testAction followed by all initial actions"
+  );
+
+  // Check the nodes in the urlbar.
+  let actualUrlbarNodeIDs = [];
+  for (
+    let node = BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    [testAction]
+      .concat(initialActionsInUrlbar)
+      .map(a => BrowserPageActions.urlbarButtonNodeIDForActionID(a.id)),
+    "urlbar nodes should be in expected order: testAction followed by all initial actions"
+  );
+
+  // Remove the test action.
+  testAction.remove();
+
+  // Check the actions in PageActions.actionsInUrlbar.
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window).map(a => a.id),
+    initialActionsInUrlbar.map(a => a.id),
+    "PageActions.actionsInUrlbar should be in expected order after removing test action: all initial actions"
+  );
+
+  // Check the nodes in the urlbar.
+  actualUrlbarNodeIDs = [];
+  for (
+    let node = BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    initialActionsInUrlbar.map(a =>
+      BrowserPageActions.urlbarButtonNodeIDForActionID(a.id)
+    ),
+    "urlbar nodes should be in expected order after removing test action: all initial actions"
+  );
+
+  // Add the test action again.
+  testAction = PageActions.addAction(
+    new PageActions.Action({
+      id,
+      title: "Test removeRetainState",
+    })
+  );
+
+  // Show its button in the urlbar again.
+  testAction.pinnedToUrlbar = true;
+
+  // Check the actions in PageActions.actionsInUrlbar.
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window).map(a => a.id),
+    [testAction].concat(initialActionsInUrlbar).map(a => a.id),
+    "PageActions.actionsInUrlbar should be in expected order after re-adding test action: testAction followed by all initial actions"
+  );
+
+  // Check the nodes in the urlbar.
+  actualUrlbarNodeIDs = [];
+  for (
+    let node = BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    [testAction]
+      .concat(initialActionsInUrlbar)
+      .map(a => BrowserPageActions.urlbarButtonNodeIDForActionID(a.id)),
+    "urlbar nodes should be in expected order after re-adding test action: testAction followed by all initial actions"
+  );
+
+  // Done, clean up.
+  testAction.remove();
+});
+
+// Tests transient actions.
+add_task(async function transient() {
+  let initialActionsInPanel = PageActions.actionsInPanel(window);
+
+  let onPlacedInPanelCount = 0;
+  let onBeforePlacedInWindowCount = 0;
+
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      id: "test-transient",
+      title: "Test transient",
+      _transient: true,
+      onPlacedInPanel(buttonNode) {
+        onPlacedInPanelCount++;
+      },
+      onBeforePlacedInWindow(win) {
+        onBeforePlacedInWindowCount++;
+      },
+    })
+  );
+
+  Assert.equal(action.__transient, true, "__transient");
+
+  Assert.equal(onPlacedInPanelCount, 0, "onPlacedInPanelCount should remain 0");
+  Assert.equal(
+    onBeforePlacedInWindowCount,
+    1,
+    "onBeforePlacedInWindowCount after adding transient action"
+  );
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_TRANSIENT_SEPARATOR, action.id]),
+    "PageActions.actionsInPanel() should be updated"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_TRANSIENT_SEPARATOR, action.id])
+      .map(id => BrowserPageActions.panelButtonNodeIDForActionID(id)),
+    "Actions in panel should be correct"
+  );
+
+  Assert.equal(
+    onPlacedInPanelCount,
+    1,
+    "onPlacedInPanelCount should be inc'ed"
+  );
+  Assert.equal(
+    onBeforePlacedInWindowCount,
+    1,
+    "onBeforePlacedInWindowCount should be inc'ed"
+  );
+
+  // Disable the action.  It should be removed from the panel.
+  action.setDisabled(true, window);
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel.map(a => a.id),
+    "PageActions.actionsInPanel() should revert to initial"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel.map(a =>
+      BrowserPageActions.panelButtonNodeIDForActionID(a.id)
+    ),
+    "Actions in panel should be correct"
+  );
+
+  // Enable the action.  It should be added back to the panel.
+  action.setDisabled(false, window);
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_TRANSIENT_SEPARATOR, action.id]),
+    "PageActions.actionsInPanel() should be updated"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_TRANSIENT_SEPARATOR, action.id])
+      .map(id => BrowserPageActions.panelButtonNodeIDForActionID(id)),
+    "Actions in panel should be correct"
+  );
+
+  Assert.equal(
+    onPlacedInPanelCount,
+    2,
+    "onPlacedInPanelCount should be inc'ed"
+  );
+  Assert.equal(
+    onBeforePlacedInWindowCount,
+    2,
+    "onBeforePlacedInWindowCount should be inc'ed"
+  );
+
+  // Add another non-built in but non-transient action.
+  let otherAction = PageActions.addAction(
+    new PageActions.Action({
+      id: "test-transient2",
+      title: "Test transient 2",
+    })
+  );
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([
+        PageActions.ACTION_ID_BUILT_IN_SEPARATOR,
+        otherAction.id,
+        PageActions.ACTION_ID_TRANSIENT_SEPARATOR,
+        action.id,
+      ]),
+    "PageActions.actionsInPanel() should be updated"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([
+        PageActions.ACTION_ID_BUILT_IN_SEPARATOR,
+        otherAction.id,
+        PageActions.ACTION_ID_TRANSIENT_SEPARATOR,
+        action.id,
+      ])
+      .map(id => BrowserPageActions.panelButtonNodeIDForActionID(id)),
+    "Actions in panel should be correct"
+  );
+
+  Assert.equal(
+    onPlacedInPanelCount,
+    2,
+    "onPlacedInPanelCount should remain the same"
+  );
+  Assert.equal(
+    onBeforePlacedInWindowCount,
+    2,
+    "onBeforePlacedInWindowCount should remain the same"
+  );
+
+  // Disable the action again.  It should be removed from the panel.
+  action.setDisabled(true, window);
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_BUILT_IN_SEPARATOR, otherAction.id]),
+    "PageActions.actionsInPanel() should be updated"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([PageActions.ACTION_ID_BUILT_IN_SEPARATOR, otherAction.id])
+      .map(id => BrowserPageActions.panelButtonNodeIDForActionID(id)),
+    "Actions in panel should be correct"
+  );
+
+  // Enable the action again.  It should be added back to the panel.
+  action.setDisabled(false, window);
+
+  Assert.deepEqual(
+    PageActions.actionsInPanel(window).map(a => a.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([
+        PageActions.ACTION_ID_BUILT_IN_SEPARATOR,
+        otherAction.id,
+        PageActions.ACTION_ID_TRANSIENT_SEPARATOR,
+        action.id,
+      ]),
+    "PageActions.actionsInPanel() should be updated"
+  );
+
+  // Check the panel.
+  await promiseOpenPageActionPanel();
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+  Assert.deepEqual(
+    Array.from(BrowserPageActions.mainViewBodyNode.children, n => n.id),
+    initialActionsInPanel
+      .map(a => a.id)
+      .concat([
+        PageActions.ACTION_ID_BUILT_IN_SEPARATOR,
+        otherAction.id,
+        PageActions.ACTION_ID_TRANSIENT_SEPARATOR,
+        action.id,
+      ])
+      .map(id => BrowserPageActions.panelButtonNodeIDForActionID(id)),
+    "Actions in panel should be correct"
+  );
+
+  Assert.equal(
+    onPlacedInPanelCount,
+    3,
+    "onPlacedInPanelCount should be inc'ed"
+  );
+  Assert.equal(
+    onBeforePlacedInWindowCount,
+    3,
+    "onBeforePlacedInWindowCount should be inc'ed"
+  );
+
+  // Done, clean up.
+  action.remove();
+  otherAction.remove();
+});
diff --git a/browser/modules/test/browser/browser_PageActions_contextMenus.js b/browser/modules/test/browser/browser_PageActions_contextMenus.js
new file mode 100644
index 0000000000..378c55c706
--- /dev/null
+++ b/browser/modules/test/browser/browser_PageActions_contextMenus.js
@@ -0,0 +1,226 @@
+"use strict";
+
+// This is a test for PageActions.sys.mjs, specifically the context menus.
+
+ChromeUtils.defineESModuleGetters(this, {
+  ExtensionCommon: "resource://gre/modules/ExtensionCommon.sys.mjs",
+});
+
+// Initialization.  Must run first.
+add_setup(async function () {
+  // The page action urlbar button, and therefore the panel, is only shown when
+  // the current tab is actionable -- i.e., a normal web page.  about:blank is
+  // not, so open a new tab first thing, and close it when this test is done.
+  let tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    url: "http://example.com/",
+  });
+  registerCleanupFunction(async () => {
+    BrowserTestUtils.removeTab(tab);
+  });
+
+  await initPageActionsTest();
+});
+
+// Opens the context menu on a non-built-in action.  (The context menu for
+// built-in actions is tested in browser_page_action_menu.js.)
+add_task(async function contextMenu() {
+  // Add an extension with a page action so we can test its context menu.
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      name: "Page action test",
+      page_action: { show_matches: ["<all_urls>"] },
+    },
+    useAddonManager: "temporary",
+  });
+  await extension.startup();
+  let actionId = ExtensionCommon.makeWidgetId(extension.id);
+
+  // Open the main panel.
+  await promiseOpenPageActionPanel();
+  let panelButton = BrowserPageActions.panelButtonNodeForActionID(actionId);
+  let cxmenu = document.getElementById("pageActionContextMenu");
+
+  let contextMenuPromise;
+  let menuItems;
+
+  // Open the context menu again on the action's button in the panel. (The
+  // panel should still be open.)
+  contextMenuPromise = promisePanelShown("pageActionContextMenu");
+  EventUtils.synthesizeMouseAtCenter(panelButton, {
+    type: "contextmenu",
+    button: 2,
+  });
+  await contextMenuPromise;
+  menuItems = collectContextMenuItems();
+  Assert.deepEqual(makeMenuItemSpecs(menuItems), makeContextMenuItemSpecs());
+
+  // Click the "manage extension" context menu item. about:addons should open.
+  let manageItemIndex = 0;
+  contextMenuPromise = promisePanelHidden("pageActionContextMenu");
+  let aboutAddonsPromise = BrowserTestUtils.waitForNewTab(
+    gBrowser,
+    "about:addons"
+  );
+  cxmenu.activateItem(menuItems[manageItemIndex]);
+  let values = await Promise.all([aboutAddonsPromise, contextMenuPromise]);
+  let aboutAddonsTab = values[0];
+  BrowserTestUtils.removeTab(aboutAddonsTab);
+
+  // Wait for the urlbar button to become visible again after about:addons is
+  // closed and the test tab becomes selected.
+  await BrowserTestUtils.waitForCondition(() => {
+    return BrowserPageActions.urlbarButtonNodeForActionID(actionId);
+  }, "Waiting for urlbar button to be added back");
+
+  // Open the context menu on the action's urlbar button.
+  let urlbarButton = BrowserPageActions.urlbarButtonNodeForActionID(actionId);
+  contextMenuPromise = promisePanelShown("pageActionContextMenu");
+  EventUtils.synthesizeMouseAtCenter(urlbarButton, {
+    type: "contextmenu",
+    button: 2,
+  });
+  await contextMenuPromise;
+  menuItems = collectContextMenuItems();
+  Assert.deepEqual(makeMenuItemSpecs(menuItems), makeContextMenuItemSpecs());
+
+  // Click the "manage" context menu item. about:addons should open.
+  contextMenuPromise = promisePanelHidden("pageActionContextMenu");
+  aboutAddonsPromise = BrowserTestUtils.waitForNewTab(gBrowser, "about:addons");
+  cxmenu.activateItem(menuItems[manageItemIndex]);
+  values = await Promise.all([aboutAddonsPromise, contextMenuPromise]);
+  aboutAddonsTab = values[0];
+  BrowserTestUtils.removeTab(aboutAddonsTab);
+
+  // Wait for the urlbar button to become visible again after about:addons is
+  // closed and the test tab becomes selected.
+  await BrowserTestUtils.waitForCondition(() => {
+    return BrowserPageActions.urlbarButtonNodeForActionID(actionId);
+  }, "Waiting for urlbar button to be added back");
+
+  // Open the context menu on the action's urlbar button.
+  urlbarButton = BrowserPageActions.urlbarButtonNodeForActionID(actionId);
+  contextMenuPromise = promisePanelShown("pageActionContextMenu");
+  EventUtils.synthesizeMouseAtCenter(urlbarButton, {
+    type: "contextmenu",
+    button: 2,
+  });
+  await contextMenuPromise;
+  menuItems = collectContextMenuItems();
+  Assert.deepEqual(makeMenuItemSpecs(menuItems), makeContextMenuItemSpecs());
+
+  // Below we'll click the "remove extension" context menu item, which first
+  // opens a prompt using the prompt service and requires confirming the prompt.
+  // Set up a mock prompt service that returns 0 to indicate that the user
+  // pressed the OK button.
+  let { prompt } = Services;
+  let promptService = {
+    QueryInterface: ChromeUtils.generateQI(["nsIPromptService"]),
+    confirmEx() {
+      return 0;
+    },
+  };
+  Services.prompt = promptService;
+  registerCleanupFunction(() => {
+    Services.prompt = prompt;
+  });
+
+  // Now click the "remove extension" context menu item.
+  let removeItemIndex = manageItemIndex + 1;
+  contextMenuPromise = promisePanelHidden("pageActionContextMenu");
+  let promiseUninstalled = promiseAddonUninstalled(extension.id);
+  cxmenu.activateItem(menuItems[removeItemIndex]);
+  await contextMenuPromise;
+  await promiseUninstalled;
+  await extension.unload();
+  Services.prompt = prompt;
+
+  // urlbar tests that run after this one can break if the mouse is left over
+  // the area where the urlbar popup appears, which seems to happen due to the
+  // above synthesized mouse events.  Move it over the urlbar.
+  EventUtils.synthesizeMouseAtCenter(gURLBar.inputField, { type: "mousemove" });
+  gURLBar.focus();
+});
+
+// The context menu shouldn't open on separators in the panel.
+add_task(async function contextMenuOnSeparator() {
+  // Add a non-built-in action so the built-in separator will appear in the
+  // panel.
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      id: "contextMenuOnSeparator",
+      title: "contextMenuOnSeparator",
+      pinnedToUrlbar: true,
+    })
+  );
+
+  // Open the panel and get the built-in separator.
+  await promiseOpenPageActionPanel();
+  let separator = BrowserPageActions.panelButtonNodeForActionID(
+    PageActions.ACTION_ID_BUILT_IN_SEPARATOR
+  );
+  Assert.ok(separator, "The built-in separator should be in the panel");
+
+  // Context-click it.  popupshowing should be fired, but by the time the event
+  // reaches this listener, preventDefault should have been called on it.
+  let showingPromise = BrowserTestUtils.waitForEvent(
+    document.getElementById("pageActionContextMenu"),
+    "popupshowing",
+    false
+  );
+  EventUtils.synthesizeMouseAtCenter(separator, {
+    type: "contextmenu",
+    button: 2,
+  });
+  let event = await showingPromise;
+  Assert.ok(
+    event.defaultPrevented,
+    "defaultPrevented should be true on popupshowing event"
+  );
+
+  // Click the main button to hide the main panel.
+  EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+  await promisePageActionPanelHidden();
+
+  action.remove();
+
+  // urlbar tests that run after this one can break if the mouse is left over
+  // the area where the urlbar popup appears, which seems to happen due to the
+  // above synthesized mouse events.  Move it over the urlbar.
+  EventUtils.synthesizeMouseAtCenter(gURLBar.inputField, { type: "mousemove" });
+  gURLBar.focus();
+});
+
+function collectContextMenuItems() {
+  let contextMenu = document.getElementById("pageActionContextMenu");
+  return Array.prototype.filter.call(contextMenu.children, node => {
+    return window.getComputedStyle(node).visibility == "visible";
+  });
+}
+
+function makeMenuItemSpecs(elements) {
+  return elements.map(e =>
+    e.localName == "menuseparator" ? {} : { label: e.label }
+  );
+}
+
+function makeContextMenuItemSpecs() {
+  let items = [
+    { label: "Manage Extension\u2026" },
+    { label: "Remove Extension" },
+  ];
+  return items;
+}
+
+function promiseAddonUninstalled(addonId) {
+  return new Promise(resolve => {
+    let listener = {};
+    listener.onUninstalled = addon => {
+      if (addon.id == addonId) {
+        AddonManager.removeAddonListener(listener);
+        resolve();
+      }
+    };
+    AddonManager.addAddonListener(listener);
+  });
+}
diff --git a/browser/modules/test/browser/browser_PageActions_newWindow.js b/browser/modules/test/browser/browser_PageActions_newWindow.js
new file mode 100644
index 0000000000..ade50c6b2c
--- /dev/null
+++ b/browser/modules/test/browser/browser_PageActions_newWindow.js
@@ -0,0 +1,377 @@
+"use strict";
+
+// This is a test for PageActions.sys.mjs, specifically the generalized parts that
+// add and remove page actions and toggle them in the urlbar.  This does not
+// test the built-in page actions; browser_page_action_menu.js does that.
+
+// Initialization.  Must run first.
+add_setup(async function () {
+  await initPageActionsTest();
+});
+
+// Makes sure that urlbar nodes appear in the correct order in a new window.
+add_task(async function urlbarOrderNewWindow() {
+  // Make some new actions.
+  let actions = [0, 1, 2].map(i => {
+    return PageActions.addAction(
+      new PageActions.Action({
+        id: `test-urlbarOrderNewWindow-${i}`,
+        title: `Test urlbarOrderNewWindow ${i}`,
+        pinnedToUrlbar: true,
+      })
+    );
+  });
+
+  // Make sure PageActions knows they're inserted before the bookmark action in
+  // the urlbar.
+  Assert.deepEqual(
+    PageActions._persistedActions.idsInUrlbar.slice(
+      PageActions._persistedActions.idsInUrlbar.length - (actions.length + 1)
+    ),
+    actions.map(a => a.id).concat([PageActions.ACTION_ID_BOOKMARK]),
+    "PageActions._persistedActions.idsInUrlbar has new actions inserted"
+  );
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window)
+      .slice(PageActions.actionsInUrlbar(window).length - (actions.length + 1))
+      .map(a => a.id),
+    actions.map(a => a.id).concat([PageActions.ACTION_ID_BOOKMARK]),
+    "PageActions.actionsInUrlbar has new actions inserted"
+  );
+
+  // Reach into _persistedActions to move the new actions to the front of the
+  // urlbar, same as if the user moved them.  That way we can test that insert-
+  // before IDs are correctly non-null when the urlbar nodes are inserted in the
+  // new window below.
+  PageActions._persistedActions.idsInUrlbar.splice(
+    PageActions._persistedActions.idsInUrlbar.length - (actions.length + 1),
+    actions.length
+  );
+  for (let i = 0; i < actions.length; i++) {
+    PageActions._persistedActions.idsInUrlbar.splice(i, 0, actions[i].id);
+  }
+
+  // Save the right-ordered IDs to use below, just in case they somehow get
+  // changed when the new window opens, which shouldn't happen, but maybe
+  // there's bugs.
+  let ids = PageActions._persistedActions.idsInUrlbar.slice();
+
+  // Make sure that worked.
+  Assert.deepEqual(
+    ids.slice(0, actions.length),
+    actions.map(a => a.id),
+    "PageActions._persistedActions.idsInUrlbar now has new actions at front"
+  );
+
+  // _persistedActions will contain the IDs of test actions added and removed
+  // above (unless PageActions._purgeUnregisteredPersistedActions() was called
+  // for all of them, which it wasn't).  Filter them out because they should
+  // not appear in the new window (or any window at this point).
+  ids = ids.filter(id => PageActions.actionForID(id));
+
+  // Open the new window.
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+
+  // Collect its urlbar nodes.
+  let actualUrlbarNodeIDs = [];
+  for (
+    let node = win.BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+
+  // Now check that they're in the right order.
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    ids.map(id => win.BrowserPageActions.urlbarButtonNodeIDForActionID(id)),
+    "Expected actions in new window's urlbar"
+  );
+
+  // Done, clean up.
+  await BrowserTestUtils.closeWindow(win);
+  for (let action of actions) {
+    action.remove();
+  }
+});
+
+// Stores version-0 (unversioned actually) persisted actions and makes sure that
+// migrating to version 1 works.
+add_task(async function migrate1() {
+  // Add a test action so we can test a non-built-in action below.
+  let actionId = "test-migrate1";
+  PageActions.addAction(
+    new PageActions.Action({
+      id: actionId,
+      title: "Test migrate1",
+      pinnedToUrlbar: true,
+    })
+  );
+
+  // Add the bookmark action first to make sure it ends up last after migration.
+  // Also include a non-default action to make sure we're not accidentally
+  // testing default behavior.
+  let ids = [PageActions.ACTION_ID_BOOKMARK, actionId];
+  let persisted = ids.reduce(
+    (memo, id) => {
+      memo.ids[id] = true;
+      memo.idsInUrlbar.push(id);
+      return memo;
+    },
+    { ids: {}, idsInUrlbar: [] }
+  );
+
+  Services.prefs.setStringPref(
+    PageActions.PREF_PERSISTED_ACTIONS,
+    JSON.stringify(persisted)
+  );
+
+  // Migrate.
+  PageActions._loadPersistedActions();
+
+  Assert.equal(PageActions._persistedActions.version, 1, "Correct version");
+
+  // expected order
+  let orderedIDs = [actionId, PageActions.ACTION_ID_BOOKMARK];
+
+  // Check the ordering.
+  Assert.deepEqual(
+    PageActions._persistedActions.idsInUrlbar,
+    orderedIDs,
+    "PageActions._persistedActions.idsInUrlbar has right order"
+  );
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window).map(a => a.id),
+    orderedIDs,
+    "PageActions.actionsInUrlbar has right order"
+  );
+
+  // Open a new window.
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.openNewForegroundTab({
+    gBrowser: win.gBrowser,
+    url: "http://example.com/",
+  });
+
+  // Collect its urlbar nodes.
+  let actualUrlbarNodeIDs = [];
+  for (
+    let node = win.BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+
+  // Now check that they're in the right order.
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    orderedIDs.map(id =>
+      win.BrowserPageActions.urlbarButtonNodeIDForActionID(id)
+    ),
+    "Expected actions in new window's urlbar"
+  );
+
+  // Done, clean up.
+  await BrowserTestUtils.closeWindow(win);
+  Services.prefs.clearUserPref(PageActions.PREF_PERSISTED_ACTIONS);
+  PageActions.actionForID(actionId).remove();
+});
+
+// Opens a new browser window and makes sure per-window state works right.
+add_task(async function perWindowState() {
+  // Add a test action.
+  let title = "Test perWindowState";
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      iconURL: "chrome://browser/skin/mail.svg",
+      id: "test-perWindowState",
+      pinnedToUrlbar: true,
+      title,
+    })
+  );
+
+  let actionsInUrlbar = PageActions.actionsInUrlbar(window);
+
+  // Open a new browser window and load an actionable page so that the action
+  // shows up in it.
+  let newWindow = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.openNewForegroundTab({
+    gBrowser: newWindow.gBrowser,
+    url: "http://example.com/",
+  });
+
+  // Set a new title globally.
+  let newGlobalTitle = title + " new title";
+  action.setTitle(newGlobalTitle);
+  Assert.equal(action.getTitle(), newGlobalTitle, "Title: global");
+  Assert.equal(action.getTitle(window), newGlobalTitle, "Title: old window");
+  Assert.equal(action.getTitle(newWindow), newGlobalTitle, "Title: new window");
+
+  // Initialize panel nodes in the windows
+  document.getElementById("pageActionButton").click();
+  await BrowserTestUtils.waitForEvent(document, "popupshowing", true);
+  newWindow.document.getElementById("pageActionButton").click();
+  await BrowserTestUtils.waitForEvent(newWindow.document, "popupshowing", true);
+
+  // The action's panel button nodes should be updated in both windows.
+  let panelButtonID = BrowserPageActions.panelButtonNodeIDForActionID(
+    action.id
+  );
+  for (let win of [window, newWindow]) {
+    win.BrowserPageActions.placeLazyActionsInPanel();
+    let panelButtonNode = win.document.getElementById(panelButtonID);
+    Assert.equal(
+      panelButtonNode.getAttribute("label"),
+      newGlobalTitle,
+      "Panel button label should be global title"
+    );
+  }
+
+  // Set a new title in the new window.
+  let newPerWinTitle = title + " new title in new window";
+  action.setTitle(newPerWinTitle, newWindow);
+  Assert.equal(
+    action.getTitle(),
+    newGlobalTitle,
+    "Title: global should remain same"
+  );
+  Assert.equal(
+    action.getTitle(window),
+    newGlobalTitle,
+    "Title: old window should remain same"
+  );
+  Assert.equal(
+    action.getTitle(newWindow),
+    newPerWinTitle,
+    "Title: new window should be new"
+  );
+
+  // The action's panel button node should be updated in the new window but the
+  // same in the old window.
+  let panelButtonNode1 = document.getElementById(panelButtonID);
+  Assert.equal(
+    panelButtonNode1.getAttribute("label"),
+    newGlobalTitle,
+    "Panel button label in old window"
+  );
+  let panelButtonNode2 = newWindow.document.getElementById(panelButtonID);
+  Assert.equal(
+    panelButtonNode2.getAttribute("label"),
+    newPerWinTitle,
+    "Panel button label in new window"
+  );
+
+  // Disable the action in the new window.
+  action.setDisabled(true, newWindow);
+  Assert.equal(
+    action.getDisabled(),
+    false,
+    "Disabled: global should remain false"
+  );
+  Assert.equal(
+    action.getDisabled(window),
+    false,
+    "Disabled: old window should remain false"
+  );
+  Assert.equal(
+    action.getDisabled(newWindow),
+    true,
+    "Disabled: new window should be true"
+  );
+
+  // Check PageActions.actionsInUrlbar for each window.
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(window).map(a => a.id),
+    actionsInUrlbar.map(a => a.id),
+    "PageActions.actionsInUrlbar: old window should have all actions in urlbar"
+  );
+  Assert.deepEqual(
+    PageActions.actionsInUrlbar(newWindow).map(a => a.id),
+    actionsInUrlbar.map(a => a.id).filter(id => id != action.id),
+    "PageActions.actionsInUrlbar: new window should have all actions in urlbar except the test action"
+  );
+
+  // Check the urlbar nodes for the old window.
+  let actualUrlbarNodeIDs = [];
+  for (
+    let node = BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    actionsInUrlbar.map(a =>
+      BrowserPageActions.urlbarButtonNodeIDForActionID(a.id)
+    ),
+    "Old window should have all nodes in urlbar"
+  );
+
+  // Check the urlbar nodes for the new window.
+  actualUrlbarNodeIDs = [];
+  for (
+    let node = newWindow.BrowserPageActions.mainButtonNode.nextElementSibling;
+    node;
+    node = node.nextElementSibling
+  ) {
+    actualUrlbarNodeIDs.push(node.id);
+  }
+  Assert.deepEqual(
+    actualUrlbarNodeIDs,
+    actionsInUrlbar
+      .filter(a => a.id != action.id)
+      .map(a => BrowserPageActions.urlbarButtonNodeIDForActionID(a.id)),
+    "New window should have all nodes in urlbar except for the test action's"
+  );
+
+  // Done, clean up.
+  await BrowserTestUtils.closeWindow(newWindow);
+  action.remove();
+});
+
+add_task(async function action_disablePrivateBrowsing() {
+  let id = "testWidget";
+  let action = PageActions.addAction(
+    new PageActions.Action({
+      id,
+      disablePrivateBrowsing: true,
+      title: "title",
+      disabled: false,
+      pinnedToUrlbar: true,
+    })
+  );
+  // Open an actionable page so that the main page action button appears.
+  let url = "http://example.com/";
+  let privateWindow = await BrowserTestUtils.openNewBrowserWindow({
+    private: true,
+  });
+  await BrowserTestUtils.openNewForegroundTab(
+    privateWindow.gBrowser,
+    url,
+    true,
+    true
+  );
+
+  Assert.ok(action.canShowInWindow(window), "should show in default window");
+  Assert.ok(
+    !action.canShowInWindow(privateWindow),
+    "should not show in private browser"
+  );
+  Assert.ok(action.shouldShowInUrlbar(window), "should show in default urlbar");
+  Assert.ok(
+    !action.shouldShowInUrlbar(privateWindow),
+    "should not show in default urlbar"
+  );
+  Assert.ok(action.shouldShowInPanel(window), "should show in default urlbar");
+  Assert.ok(
+    !action.shouldShowInPanel(privateWindow),
+    "should not show in default urlbar"
+  );
+
+  action.remove();
+
+  privateWindow.close();
+});
diff --git a/browser/modules/test/browser/browser_PermissionUI.js b/browser/modules/test/browser/browser_PermissionUI.js
new file mode 100644
index 0000000000..8b66734093
--- /dev/null
+++ b/browser/modules/test/browser/browser_PermissionUI.js
@@ -0,0 +1,692 @@
+/**
+ * These tests test the ability for the PermissionUI module to open
+ * permission prompts to the user. It also tests to ensure that
+ * add-ons can introduce their own permission prompts.
+ */
+
+"use strict";
+
+const { PermissionUI } = ChromeUtils.importESModule(
+  "resource:///modules/PermissionUI.sys.mjs"
+);
+
+const { PermissionTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PermissionTestUtils.sys.mjs"
+);
+
+/**
+ * Tests the PermissionPromptForRequest prototype to ensure that a prompt
+ * can be displayed. Does not test permission handling.
+ */
+add_task(async function test_permission_prompt_for_request() {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com/",
+    },
+    async function (browser) {
+      const kTestNotificationID = "test-notification";
+      const kTestMessage = "Test message";
+      let mainAction = {
+        label: "Main",
+        accessKey: "M",
+      };
+      let secondaryAction = {
+        label: "Secondary",
+        accessKey: "S",
+      };
+
+      let mockRequest = makeMockPermissionRequest(browser);
+      class TestPrompt extends PermissionUI.PermissionPromptForRequest {
+        get request() {
+          return mockRequest;
+        }
+        get notificationID() {
+          return kTestNotificationID;
+        }
+        get message() {
+          return kTestMessage;
+        }
+        get promptActions() {
+          return [mainAction, secondaryAction];
+        }
+      }
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+      let notification = PopupNotifications.getNotification(
+        kTestNotificationID,
+        browser
+      );
+      Assert.ok(notification, "Should have gotten the notification");
+
+      Assert.equal(
+        notification.message,
+        kTestMessage,
+        "Should be showing the right message"
+      );
+      Assert.equal(
+        notification.mainAction.label,
+        mainAction.label,
+        "The main action should have the right label"
+      );
+      Assert.equal(
+        notification.mainAction.accessKey,
+        mainAction.accessKey,
+        "The main action should have the right access key"
+      );
+      Assert.equal(
+        notification.secondaryActions.length,
+        1,
+        "There should only be 1 secondary action"
+      );
+      Assert.equal(
+        notification.secondaryActions[0].label,
+        secondaryAction.label,
+        "The secondary action should have the right label"
+      );
+      Assert.equal(
+        notification.secondaryActions[0].accessKey,
+        secondaryAction.accessKey,
+        "The secondary action should have the right access key"
+      );
+      Assert.ok(
+        notification.options.displayURI.equals(mockRequest.principal.URI),
+        "Should be showing the URI of the requesting page"
+      );
+
+      let removePromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popuphidden"
+      );
+      notification.remove();
+      await removePromise;
+    }
+  );
+});
+
+/**
+ * Tests that if the PermissionPrompt sets displayURI to false in popupOptions,
+ * then there is no URI shown on the popupnotification.
+ */
+add_task(async function test_permission_prompt_for_popupOptions() {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com/",
+    },
+    async function (browser) {
+      const kTestNotificationID = "test-notification";
+      const kTestMessage = "Test message";
+      let mainAction = {
+        label: "Main",
+        accessKey: "M",
+      };
+      let secondaryAction = {
+        label: "Secondary",
+        accessKey: "S",
+      };
+
+      let mockRequest = makeMockPermissionRequest(browser);
+      class TestPrompt extends PermissionUI.PermissionPromptForRequest {
+        get request() {
+          return mockRequest;
+        }
+        get notificationID() {
+          return kTestNotificationID;
+        }
+        get message() {
+          return kTestMessage;
+        }
+        get promptActions() {
+          return [mainAction, secondaryAction];
+        }
+        get popupOptions() {
+          return {
+            displayURI: false,
+          };
+        }
+      }
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+      let notification = PopupNotifications.getNotification(
+        kTestNotificationID,
+        browser
+      );
+
+      Assert.ok(
+        !notification.options.displayURI,
+        "Should not show the URI of the requesting page"
+      );
+
+      let removePromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popuphidden"
+      );
+      notification.remove();
+      await removePromise;
+    }
+  );
+});
+
+/**
+ * Tests that if the PermissionPrompt has the permissionKey
+ * set that permissions can be set properly by the user. Also
+ * ensures that callbacks for promptActions are properly fired.
+ */
+add_task(async function test_with_permission_key() {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com",
+    },
+    async function (browser) {
+      const kTestNotificationID = "test-notification";
+      const kTestMessage = "Test message";
+      const kTestPermissionKey = "test-permission-key";
+
+      let allowed = false;
+      let mainAction = {
+        label: "Allow",
+        accessKey: "M",
+        action: SitePermissions.ALLOW,
+        callback() {
+          allowed = true;
+        },
+      };
+
+      let denied = false;
+      let secondaryAction = {
+        label: "Deny",
+        accessKey: "D",
+        action: SitePermissions.BLOCK,
+        callback() {
+          denied = true;
+        },
+      };
+
+      let mockRequest = makeMockPermissionRequest(browser);
+      let principal = mockRequest.principal;
+      registerCleanupFunction(function () {
+        PermissionTestUtils.remove(principal.URI, kTestPermissionKey);
+      });
+      class TestPrompt extends PermissionUI.PermissionPromptForRequest {
+        get request() {
+          return mockRequest;
+        }
+        get notificationID() {
+          return kTestNotificationID;
+        }
+        get permissionKey() {
+          return kTestPermissionKey;
+        }
+        get message() {
+          return kTestMessage;
+        }
+        get promptActions() {
+          return [mainAction, secondaryAction];
+        }
+        get popupOptions() {
+          return {
+            checkbox: {
+              label: "Remember this decision",
+              show: true,
+              checked: true,
+            },
+          };
+        }
+      }
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+      let notification = PopupNotifications.getNotification(
+        kTestNotificationID,
+        browser
+      );
+      Assert.ok(notification, "Should have gotten the notification");
+
+      let curPerm = SitePermissions.getForPrincipal(
+        principal,
+        kTestPermissionKey,
+        browser
+      );
+      Assert.equal(
+        curPerm.state,
+        SitePermissions.UNKNOWN,
+        "Should be no permission set to begin with."
+      );
+
+      // First test denying the permission request without the checkbox checked.
+      let popupNotification = getPopupNotificationNode();
+      popupNotification.checkbox.checked = false;
+
+      Assert.equal(
+        notification.secondaryActions.length,
+        1,
+        "There should only be 1 secondary action"
+      );
+      await clickSecondaryAction();
+      curPerm = SitePermissions.getForPrincipal(
+        principal,
+        kTestPermissionKey,
+        browser
+      );
+      Assert.deepEqual(
+        curPerm,
+        {
+          state: SitePermissions.BLOCK,
+          scope: SitePermissions.SCOPE_TEMPORARY,
+        },
+        "Should have denied the action temporarily"
+      );
+      // Try getting the permission without passing the browser object (should fail).
+      curPerm = PermissionTestUtils.getPermissionObject(
+        principal.URI,
+        kTestPermissionKey
+      );
+      Assert.equal(
+        curPerm,
+        null,
+        "Should have made no permanent permission entry"
+      );
+      Assert.ok(denied, "The secondaryAction callback should have fired");
+      Assert.ok(!allowed, "The mainAction callback should not have fired");
+      Assert.ok(
+        mockRequest._cancelled,
+        "The request should have been cancelled"
+      );
+      Assert.ok(
+        !mockRequest._allowed,
+        "The request should not have been allowed"
+      );
+
+      // Clear the permission and pretend we never denied
+      SitePermissions.removeFromPrincipal(
+        principal,
+        kTestPermissionKey,
+        browser
+      );
+      denied = false;
+      mockRequest._cancelled = false;
+
+      // Bring the PopupNotification back up now...
+      shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+
+      // Test denying the permission request.
+      Assert.equal(
+        notification.secondaryActions.length,
+        1,
+        "There should only be 1 secondary action"
+      );
+      await clickSecondaryAction();
+      curPerm = PermissionTestUtils.getPermissionObject(
+        principal.URI,
+        kTestPermissionKey
+      );
+      Assert.equal(
+        curPerm.capability,
+        Services.perms.DENY_ACTION,
+        "Should have denied the action"
+      );
+      Assert.equal(curPerm.expireTime, 0, "Deny should be permanent");
+      Assert.ok(denied, "The secondaryAction callback should have fired");
+      Assert.ok(!allowed, "The mainAction callback should not have fired");
+      Assert.ok(
+        mockRequest._cancelled,
+        "The request should have been cancelled"
+      );
+      Assert.ok(
+        !mockRequest._allowed,
+        "The request should not have been allowed"
+      );
+
+      // Clear the permission and pretend we never denied
+      PermissionTestUtils.remove(principal.URI, kTestPermissionKey);
+      denied = false;
+      mockRequest._cancelled = false;
+
+      // Bring the PopupNotification back up now...
+      shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+
+      // Test allowing the permission request.
+      await clickMainAction();
+      curPerm = PermissionTestUtils.getPermissionObject(
+        principal.URI,
+        kTestPermissionKey
+      );
+      Assert.equal(
+        curPerm.capability,
+        Services.perms.ALLOW_ACTION,
+        "Should have allowed the action"
+      );
+      Assert.equal(curPerm.expireTime, 0, "Allow should be permanent");
+      Assert.ok(!denied, "The secondaryAction callback should not have fired");
+      Assert.ok(allowed, "The mainAction callback should have fired");
+      Assert.ok(
+        !mockRequest._cancelled,
+        "The request should not have been cancelled"
+      );
+      Assert.ok(mockRequest._allowed, "The request should have been allowed");
+    }
+  );
+});
+
+/**
+ * Tests that the onBeforeShow method will be called before
+ * the popup appears.
+ */
+add_task(async function test_on_before_show() {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com",
+    },
+    async function (browser) {
+      const kTestNotificationID = "test-notification";
+      const kTestMessage = "Test message";
+
+      let mainAction = {
+        label: "Test action",
+        accessKey: "T",
+      };
+
+      let mockRequest = makeMockPermissionRequest(browser);
+      let beforeShown = false;
+      class TestPrompt extends PermissionUI.PermissionPromptForRequest {
+        get request() {
+          return mockRequest;
+        }
+        get notificationID() {
+          return kTestNotificationID;
+        }
+        get message() {
+          return kTestMessage;
+        }
+        get promptActions() {
+          return [mainAction];
+        }
+        get popupOptions() {
+          return {
+            checkbox: {
+              label: "Remember this decision",
+              show: true,
+              checked: true,
+            },
+          };
+        }
+        onBeforeShow() {
+          beforeShown = true;
+          return true;
+        }
+      }
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      Assert.ok(beforeShown, "Should have called onBeforeShown");
+      await shownPromise;
+      let notification = PopupNotifications.getNotification(
+        kTestNotificationID,
+        browser
+      );
+
+      let removePromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popuphidden"
+      );
+      notification.remove();
+      await removePromise;
+    }
+  );
+});
+
+/**
+ * Tests that we can open a PermissionPrompt without wrapping a
+ * nsIContentPermissionRequest.
+ */
+add_task(async function test_no_request() {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com",
+    },
+    async function (browser) {
+      const kTestNotificationID = "test-notification";
+      let allowed = false;
+      let mainAction = {
+        label: "Allow",
+        accessKey: "M",
+        callback() {
+          allowed = true;
+        },
+      };
+
+      let denied = false;
+      let secondaryAction = {
+        label: "Deny",
+        accessKey: "D",
+        callback() {
+          denied = true;
+        },
+      };
+
+      const kTestMessage = "Test message with no request";
+      let principal = browser.contentPrincipal;
+      let beforeShown = false;
+      class TestPrompt extends PermissionUI.PermissionPromptForRequest {
+        get notificationID() {
+          return kTestNotificationID;
+        }
+        get principal() {
+          return principal;
+        }
+        get browser() {
+          return browser;
+        }
+        get message() {
+          return kTestMessage;
+        }
+        get promptActions() {
+          return [mainAction, secondaryAction];
+        }
+        onBeforeShow() {
+          beforeShown = true;
+          return true;
+        }
+      }
+
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      Assert.ok(beforeShown, "Should have called onBeforeShown");
+      await shownPromise;
+      let notification = PopupNotifications.getNotification(
+        kTestNotificationID,
+        browser
+      );
+
+      Assert.equal(
+        notification.message,
+        kTestMessage,
+        "Should be showing the right message"
+      );
+      Assert.equal(
+        notification.mainAction.label,
+        mainAction.label,
+        "The main action should have the right label"
+      );
+      Assert.equal(
+        notification.mainAction.accessKey,
+        mainAction.accessKey,
+        "The main action should have the right access key"
+      );
+      Assert.equal(
+        notification.secondaryActions.length,
+        1,
+        "There should only be 1 secondary action"
+      );
+      Assert.equal(
+        notification.secondaryActions[0].label,
+        secondaryAction.label,
+        "The secondary action should have the right label"
+      );
+      Assert.equal(
+        notification.secondaryActions[0].accessKey,
+        secondaryAction.accessKey,
+        "The secondary action should have the right access key"
+      );
+      Assert.ok(
+        notification.options.displayURI.equals(principal.URI),
+        "Should be showing the URI of the requesting page"
+      );
+
+      // First test denying the permission request.
+      Assert.equal(
+        notification.secondaryActions.length,
+        1,
+        "There should only be 1 secondary action"
+      );
+      await clickSecondaryAction();
+      Assert.ok(denied, "The secondaryAction callback should have fired");
+      Assert.ok(!allowed, "The mainAction callback should not have fired");
+
+      shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+
+      // Next test allowing the permission request.
+      await clickMainAction();
+      Assert.ok(allowed, "The mainAction callback should have fired");
+    }
+  );
+});
+
+/**
+ * Tests that when the tab is moved to a different window, the notification
+ * is transferred to the new window.
+ */
+add_task(async function test_window_swap() {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com",
+    },
+    async function (browser) {
+      const kTestNotificationID = "test-notification";
+      const kTestMessage = "Test message";
+
+      let mainAction = {
+        label: "Test action",
+        accessKey: "T",
+      };
+      let secondaryAction = {
+        label: "Secondary",
+        accessKey: "S",
+      };
+
+      let mockRequest = makeMockPermissionRequest(browser);
+      class TestPrompt extends PermissionUI.PermissionPromptForRequest {
+        get request() {
+          return mockRequest;
+        }
+        get notificationID() {
+          return kTestNotificationID;
+        }
+        get message() {
+          return kTestMessage;
+        }
+        get promptActions() {
+          return [mainAction, secondaryAction];
+        }
+      }
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      new TestPrompt().prompt();
+      await shownPromise;
+
+      let newWindowOpened = BrowserTestUtils.waitForNewWindow();
+      gBrowser.replaceTabWithWindow(gBrowser.selectedTab);
+      let newWindow = await newWindowOpened;
+      // We may have already opened the panel, because it was open before we moved the tab.
+      if (newWindow.PopupNotifications.panel.state != "open") {
+        shownPromise = BrowserTestUtils.waitForEvent(
+          newWindow.PopupNotifications.panel,
+          "popupshown"
+        );
+        new TestPrompt().prompt();
+        await shownPromise;
+      }
+
+      let notification = newWindow.PopupNotifications.getNotification(
+        kTestNotificationID,
+        newWindow.gBrowser.selectedBrowser
+      );
+      Assert.ok(notification, "Should have gotten the notification");
+
+      Assert.equal(
+        notification.message,
+        kTestMessage,
+        "Should be showing the right message"
+      );
+      Assert.equal(
+        notification.mainAction.label,
+        mainAction.label,
+        "The main action should have the right label"
+      );
+      Assert.equal(
+        notification.mainAction.accessKey,
+        mainAction.accessKey,
+        "The main action should have the right access key"
+      );
+      Assert.equal(
+        notification.secondaryActions.length,
+        1,
+        "There should only be 1 secondary action"
+      );
+      Assert.equal(
+        notification.secondaryActions[0].label,
+        secondaryAction.label,
+        "The secondary action should have the right label"
+      );
+      Assert.equal(
+        notification.secondaryActions[0].accessKey,
+        secondaryAction.accessKey,
+        "The secondary action should have the right access key"
+      );
+      Assert.ok(
+        notification.options.displayURI.equals(mockRequest.principal.URI),
+        "Should be showing the URI of the requesting page"
+      );
+
+      await BrowserTestUtils.closeWindow(newWindow);
+    }
+  );
+});
diff --git a/browser/modules/test/browser/browser_PermissionUI_prompts.js b/browser/modules/test/browser/browser_PermissionUI_prompts.js
new file mode 100644
index 0000000000..777e5a4a86
--- /dev/null
+++ b/browser/modules/test/browser/browser_PermissionUI_prompts.js
@@ -0,0 +1,284 @@
+/**
+ * These tests test the ability for the PermissionUI module to open
+ * permission prompts to the user. It also tests to ensure that
+ * add-ons can introduce their own permission prompts.
+ */
+
+"use strict";
+
+const { PermissionUI } = ChromeUtils.importESModule(
+  "resource:///modules/PermissionUI.sys.mjs"
+);
+const { SITEPERMS_ADDON_PROVIDER_PREF } = ChromeUtils.importESModule(
+  "resource://gre/modules/addons/siteperms-addon-utils.sys.mjs"
+);
+
+// Tests that GeolocationPermissionPrompt works as expected
+add_task(async function test_geo_permission_prompt() {
+  await testPrompt(PermissionUI.GeolocationPermissionPrompt);
+});
+
+// Tests that GeolocationPermissionPrompt works as expected with local files
+add_task(async function test_geo_permission_prompt_local_file() {
+  await testPrompt(PermissionUI.GeolocationPermissionPrompt, true);
+});
+
+// Tests that XRPermissionPrompt works as expected
+add_task(async function test_xr_permission_prompt() {
+  await testPrompt(PermissionUI.XRPermissionPrompt);
+});
+
+// Tests that XRPermissionPrompt works as expected with local files
+add_task(async function test_xr_permission_prompt_local_file() {
+  await testPrompt(PermissionUI.XRPermissionPrompt, true);
+});
+
+// Tests that DesktopNotificationPermissionPrompt works as expected
+add_task(async function test_desktop_notification_permission_prompt() {
+  Services.prefs.setBoolPref(
+    "dom.webnotifications.requireuserinteraction",
+    false
+  );
+  Services.prefs.setBoolPref(
+    "permissions.desktop-notification.notNow.enabled",
+    true
+  );
+  await testPrompt(PermissionUI.DesktopNotificationPermissionPrompt);
+  Services.prefs.clearUserPref("dom.webnotifications.requireuserinteraction");
+  Services.prefs.clearUserPref(
+    "permissions.desktop-notification.notNow.enabled"
+  );
+});
+
+// Tests that PersistentStoragePermissionPrompt works as expected
+add_task(async function test_persistent_storage_permission_prompt() {
+  await testPrompt(PermissionUI.PersistentStoragePermissionPrompt);
+});
+
+// Tests that MidiPrompt works as expected
+add_task(async function test_midi_permission_prompt() {
+  if (Services.prefs.getBoolPref(SITEPERMS_ADDON_PROVIDER_PREF, false)) {
+    ok(
+      true,
+      "PermissionUI.MIDIPermissionPrompt uses SitePermsAddon install flow"
+    );
+    return;
+  }
+  await testPrompt(PermissionUI.MIDIPermissionPrompt);
+});
+
+// Tests that MidiPrompt works as expected with local files
+add_task(async function test_midi_permission_prompt_local_file() {
+  if (Services.prefs.getBoolPref(SITEPERMS_ADDON_PROVIDER_PREF, false)) {
+    ok(
+      true,
+      "PermissionUI.MIDIPermissionPrompt uses SitePermsAddon install flow"
+    );
+    return;
+  }
+  await testPrompt(PermissionUI.MIDIPermissionPrompt, true);
+});
+
+// Tests that StoragePermissionPrompt works as expected
+add_task(async function test_storage_access_permission_prompt() {
+  Services.prefs.setBoolPref("dom.storage_access.auto_grants", false);
+  await testPrompt(PermissionUI.StorageAccessPermissionPrompt);
+  Services.prefs.clearUserPref("dom.storage_access.auto_grants");
+});
+
+async function testPrompt(Prompt, useLocalFile = false) {
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: useLocalFile ? `file://${PathUtils.tempDir}` : "http://example.com",
+    },
+    async function (browser) {
+      let mockRequest = makeMockPermissionRequest(browser);
+      let principal = mockRequest.principal;
+      let TestPrompt = new Prompt(mockRequest);
+      let { usePermissionManager, permissionKey } = TestPrompt;
+
+      registerCleanupFunction(function () {
+        if (permissionKey) {
+          SitePermissions.removeFromPrincipal(
+            principal,
+            permissionKey,
+            browser
+          );
+        }
+      });
+
+      let shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      TestPrompt.prompt();
+      await shownPromise;
+      let notification = PopupNotifications.getNotification(
+        TestPrompt.notificationID,
+        browser
+      );
+      Assert.ok(notification, "Should have gotten the notification");
+
+      let curPerm;
+      if (permissionKey) {
+        curPerm = SitePermissions.getForPrincipal(
+          principal,
+          permissionKey,
+          browser
+        );
+        Assert.equal(
+          curPerm.state,
+          SitePermissions.UNKNOWN,
+          "Should be no permission set to begin with."
+        );
+      }
+
+      // First test denying the permission request without the checkbox checked.
+      let popupNotification = getPopupNotificationNode();
+      popupNotification.checkbox.checked = false;
+
+      let isNotificationPrompt =
+        Prompt == PermissionUI.DesktopNotificationPermissionPrompt;
+
+      let expectedSecondaryActionsCount = isNotificationPrompt ? 2 : 1;
+      Assert.equal(
+        notification.secondaryActions.length,
+        expectedSecondaryActionsCount,
+        "There should only be " +
+          expectedSecondaryActionsCount +
+          " secondary action(s)"
+      );
+      await clickSecondaryAction();
+      if (permissionKey) {
+        curPerm = SitePermissions.getForPrincipal(
+          principal,
+          permissionKey,
+          browser
+        );
+        Assert.deepEqual(
+          curPerm,
+          {
+            state: SitePermissions.BLOCK,
+            scope: SitePermissions.SCOPE_TEMPORARY,
+          },
+          "Should have denied the action temporarily"
+        );
+
+        Assert.ok(
+          mockRequest._cancelled,
+          "The request should have been cancelled"
+        );
+        Assert.ok(
+          !mockRequest._allowed,
+          "The request should not have been allowed"
+        );
+      }
+
+      SitePermissions.removeFromPrincipal(
+        principal,
+        TestPrompt.permissionKey,
+        browser
+      );
+      mockRequest._cancelled = false;
+
+      // Bring the PopupNotification back up now...
+      shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      TestPrompt.prompt();
+      await shownPromise;
+
+      // Test denying the permission request with the checkbox checked (for geolocation)
+      // or by clicking the "never" option from the dropdown (for notifications and persistent-storage).
+      popupNotification = getPopupNotificationNode();
+      let secondaryActionToClickIndex = 0;
+      if (isNotificationPrompt) {
+        secondaryActionToClickIndex = 1;
+      } else {
+        popupNotification.checkbox.checked = true;
+      }
+
+      Assert.equal(
+        notification.secondaryActions.length,
+        expectedSecondaryActionsCount,
+        "There should only be " +
+          expectedSecondaryActionsCount +
+          " secondary action(s)"
+      );
+      await clickSecondaryAction(secondaryActionToClickIndex);
+      if (permissionKey) {
+        curPerm = SitePermissions.getForPrincipal(
+          principal,
+          permissionKey,
+          browser
+        );
+        Assert.equal(
+          curPerm.state,
+          SitePermissions.BLOCK,
+          "Should have denied the action"
+        );
+
+        let expectedScope = usePermissionManager
+          ? SitePermissions.SCOPE_PERSISTENT
+          : SitePermissions.SCOPE_TEMPORARY;
+        Assert.equal(
+          curPerm.scope,
+          expectedScope,
+          `Deny should be ${usePermissionManager ? "persistent" : "temporary"}`
+        );
+
+        Assert.ok(
+          mockRequest._cancelled,
+          "The request should have been cancelled"
+        );
+        Assert.ok(
+          !mockRequest._allowed,
+          "The request should not have been allowed"
+        );
+      }
+
+      SitePermissions.removeFromPrincipal(principal, permissionKey, browser);
+      mockRequest._cancelled = false;
+
+      // Bring the PopupNotification back up now...
+      shownPromise = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popupshown"
+      );
+      TestPrompt.prompt();
+      await shownPromise;
+
+      // Test allowing the permission request with the checkbox checked.
+      popupNotification = getPopupNotificationNode();
+      popupNotification.checkbox.checked = true;
+
+      await clickMainAction();
+      // If the prompt does not use the permission manager, it can not set a
+      // persistent allow. Temporary allow is not supported.
+      if (usePermissionManager && permissionKey) {
+        curPerm = SitePermissions.getForPrincipal(
+          principal,
+          permissionKey,
+          browser
+        );
+        Assert.equal(
+          curPerm.state,
+          SitePermissions.ALLOW,
+          "Should have allowed the action"
+        );
+        Assert.equal(
+          curPerm.scope,
+          SitePermissions.SCOPE_PERSISTENT,
+          "Allow should be permanent"
+        );
+        Assert.ok(
+          !mockRequest._cancelled,
+          "The request should not have been cancelled"
+        );
+        Assert.ok(mockRequest._allowed, "The request should have been allowed");
+      }
+    }
+  );
+}
diff --git a/browser/modules/test/browser/browser_ProcessHangNotifications.js b/browser/modules/test/browser/browser_ProcessHangNotifications.js
new file mode 100644
index 0000000000..d176f911ef
--- /dev/null
+++ b/browser/modules/test/browser/browser_ProcessHangNotifications.js
@@ -0,0 +1,484 @@
+/* globals ProcessHangMonitor */
+
+const { WebExtensionPolicy } = Cu.getGlobalForObject(Services);
+
+function promiseNotificationShown(aWindow, aName) {
+  return new Promise(resolve => {
+    let notificationBox = aWindow.gNotificationBox;
+    notificationBox.stack.addEventListener(
+      "AlertActive",
+      function () {
+        is(
+          notificationBox.allNotifications.length,
+          1,
+          "Notification Displayed."
+        );
+        resolve(notificationBox);
+      },
+      { once: true }
+    );
+  });
+}
+
+function pushPrefs(...aPrefs) {
+  return SpecialPowers.pushPrefEnv({ set: aPrefs });
+}
+
+function popPrefs() {
+  return SpecialPowers.popPrefEnv();
+}
+
+const TEST_ACTION_UNKNOWN = 0;
+const TEST_ACTION_CANCELLED = 1;
+const TEST_ACTION_TERMSCRIPT = 2;
+const TEST_ACTION_TERMGLOBAL = 3;
+const SLOW_SCRIPT = 1;
+const ADDON_HANG = 3;
+const ADDON_ID = "fake-addon";
+
+/**
+ * A mock nsIHangReport that we can pass through nsIObserverService
+ * to trigger notifications.
+ *
+ * @param hangType
+ *        One of SLOW_SCRIPT, ADDON_HANG.
+ * @param browser (optional)
+ *        The <xul:browser> that this hang should be associated with.
+ *        If not supplied, the hang will be associated with every browser,
+ *        but the nsIHangReport.scriptBrowser attribute will return the
+ *        currently selected browser in this window's gBrowser.
+ */
+let TestHangReport = function (
+  hangType = SLOW_SCRIPT,
+  browser = gBrowser.selectedBrowser
+) {
+  this.promise = new Promise((resolve, reject) => {
+    this._resolver = resolve;
+  });
+
+  if (hangType == ADDON_HANG) {
+    // Add-on hangs need an associated add-on ID for us to blame.
+    this._addonId = ADDON_ID;
+  }
+
+  this._browser = browser;
+};
+
+TestHangReport.prototype = {
+  get addonId() {
+    return this._addonId;
+  },
+
+  QueryInterface: ChromeUtils.generateQI(["nsIHangReport"]),
+
+  userCanceled() {
+    this._resolver(TEST_ACTION_CANCELLED);
+  },
+
+  terminateScript() {
+    this._resolver(TEST_ACTION_TERMSCRIPT);
+  },
+
+  isReportForBrowserOrChildren(aFrameLoader) {
+    if (this._browser) {
+      return this._browser.frameLoader === aFrameLoader;
+    }
+
+    return true;
+  },
+
+  get scriptBrowser() {
+    return this._browser;
+  },
+
+  // Shut up warnings about this property missing:
+  get scriptFileName() {
+    return "chrome://browser/content/browser.js";
+  },
+};
+
+// on dev edition we add a button for js debugging of hung scripts.
+let buttonCount = AppConstants.MOZ_DEV_EDITION ? 2 : 1;
+
+add_setup(async function () {
+  // Create a fake WebExtensionPolicy that we can use for
+  // the add-on hang notification.
+  const uuidGen = Services.uuid;
+  const uuid = uuidGen.generateUUID().number.slice(1, -1);
+  let policy = new WebExtensionPolicy({
+    name: "Scapegoat",
+    id: ADDON_ID,
+    mozExtensionHostname: uuid,
+    baseURL: "file:///",
+    allowedOrigins: new MatchPatternSet([]),
+    localizeCallback() {},
+  });
+  policy.active = true;
+
+  registerCleanupFunction(() => {
+    policy.active = false;
+  });
+});
+
+/**
+ * Test if hang reports receive a terminate script callback when the user selects
+ * stop in response to a script hang.
+ */
+add_task(async function terminateScriptTest() {
+  let promise = promiseNotificationShown(window, "process-hang");
+  let hangReport = new TestHangReport();
+  Services.obs.notifyObservers(hangReport, "process-hang-report");
+  let notification = await promise;
+
+  let buttons =
+    notification.currentNotification.buttonContainer.getElementsByTagName(
+      "button"
+    );
+  is(buttons.length, buttonCount, "proper number of buttons");
+
+  // Click the "Stop" button, we should get a terminate script callback
+  buttons[0].click();
+  let action = await hangReport.promise;
+  is(
+    action,
+    TEST_ACTION_TERMSCRIPT,
+    "Clicking 'Stop' should have terminated the script."
+  );
+});
+
+/**
+ * Test if hang reports receive user canceled callbacks after a user selects wait
+ * and the browser frees up from a script hang on its own.
+ */
+add_task(async function waitForScriptTest() {
+  let hangReport = new TestHangReport();
+  let promise = promiseNotificationShown(window, "process-hang");
+  Services.obs.notifyObservers(hangReport, "process-hang-report");
+  let notification = await promise;
+
+  let buttons =
+    notification.currentNotification.buttonContainer.getElementsByTagName(
+      "button"
+    );
+  is(buttons.length, buttonCount, "proper number of buttons");
+
+  await pushPrefs(["browser.hangNotification.waitPeriod", 1000]);
+
+  let ignoringReport = true;
+
+  hangReport.promise.then(action => {
+    if (ignoringReport) {
+      ok(
+        false,
+        "Hang report was somehow dealt with when it " +
+          "should have been ignored."
+      );
+    } else {
+      is(
+        action,
+        TEST_ACTION_CANCELLED,
+        "Hang report should have been cancelled."
+      );
+    }
+  });
+
+  // Click the "Close" button this time, we shouldn't get a callback at all.
+  notification.currentNotification.closeButtonEl.click();
+
+  // send another hang pulse, we should not get a notification here
+  Services.obs.notifyObservers(hangReport, "process-hang-report");
+  is(
+    notification.currentNotification,
+    null,
+    "no notification should be visible"
+  );
+
+  // Make sure that any queued Promises have run to give our report-ignoring
+  // then() a chance to fire.
+  await Promise.resolve();
+
+  ignoringReport = false;
+  Services.obs.notifyObservers(hangReport, "clear-hang-report");
+
+  await popPrefs();
+});
+
+/**
+ * Test if hang reports receive user canceled callbacks after the content
+ * process stops sending hang notifications.
+ */
+add_task(async function hangGoesAwayTest() {
+  await pushPrefs(["browser.hangNotification.expiration", 1000]);
+
+  let hangReport = new TestHangReport();
+  let promise = promiseNotificationShown(window, "process-hang");
+  Services.obs.notifyObservers(hangReport, "process-hang-report");
+  await promise;
+
+  Services.obs.notifyObservers(hangReport, "clear-hang-report");
+  let action = await hangReport.promise;
+  is(action, TEST_ACTION_CANCELLED, "Hang report should have been cancelled.");
+
+  await popPrefs();
+});
+
+/**
+ * Tests that if we're shutting down, any pre-existing hang reports will
+ * be terminated appropriately.
+ */
+add_task(async function terminateAtShutdown() {
+  let pausedHang = new TestHangReport(SLOW_SCRIPT);
+  Services.obs.notifyObservers(pausedHang, "process-hang-report");
+  ProcessHangMonitor.waitLonger(window);
+  ok(
+    ProcessHangMonitor.findPausedReport(gBrowser.selectedBrowser),
+    "There should be a paused report for the selected browser."
+  );
+
+  let scriptHang = new TestHangReport(SLOW_SCRIPT);
+  let addonHang = new TestHangReport(ADDON_HANG);
+
+  [scriptHang, addonHang].forEach(hangReport => {
+    Services.obs.notifyObservers(hangReport, "process-hang-report");
+  });
+
+  // Simulate the browser being told to shutdown. This should cause
+  // hangs to terminate scripts.
+  ProcessHangMonitor.onQuitApplicationGranted();
+
+  // In case this test happens to throw before it can finish, make
+  // sure to reset the shutting-down state.
+  registerCleanupFunction(() => {
+    ProcessHangMonitor._shuttingDown = false;
+  });
+
+  let pausedAction = await pausedHang.promise;
+  let scriptAction = await scriptHang.promise;
+  let addonAction = await addonHang.promise;
+
+  is(
+    pausedAction,
+    TEST_ACTION_TERMSCRIPT,
+    "On shutdown, should have terminated script for paused script hang."
+  );
+  is(
+    scriptAction,
+    TEST_ACTION_TERMSCRIPT,
+    "On shutdown, should have terminated script for script hang."
+  );
+  is(
+    addonAction,
+    TEST_ACTION_TERMSCRIPT,
+    "On shutdown, should have terminated script for add-on hang."
+  );
+
+  // ProcessHangMonitor should now be in the "shutting down" state,
+  // meaning that any further hangs should be handled immediately
+  // without user interaction.
+  let scriptHang2 = new TestHangReport(SLOW_SCRIPT);
+  let addonHang2 = new TestHangReport(ADDON_HANG);
+
+  [scriptHang2, addonHang2].forEach(hangReport => {
+    Services.obs.notifyObservers(hangReport, "process-hang-report");
+  });
+
+  let scriptAction2 = await scriptHang.promise;
+  let addonAction2 = await addonHang.promise;
+
+  is(
+    scriptAction2,
+    TEST_ACTION_TERMSCRIPT,
+    "On shutdown, should have terminated script for script hang."
+  );
+  is(
+    addonAction2,
+    TEST_ACTION_TERMSCRIPT,
+    "On shutdown, should have terminated script for add-on hang."
+  );
+
+  ProcessHangMonitor._shuttingDown = false;
+});
+
+/**
+ * Test that if there happens to be no open browser windows, that any
+ * hang reports that exist or appear while in this state will be handled
+ * automatically.
+ */
+add_task(async function terminateNoWindows() {
+  let testWin = await BrowserTestUtils.openNewBrowserWindow();
+
+  let pausedHang = new TestHangReport(
+    SLOW_SCRIPT,
+    testWin.gBrowser.selectedBrowser
+  );
+  Services.obs.notifyObservers(pausedHang, "process-hang-report");
+  ProcessHangMonitor.waitLonger(testWin);
+  ok(
+    ProcessHangMonitor.findPausedReport(testWin.gBrowser.selectedBrowser),
+    "There should be a paused report for the selected browser."
+  );
+
+  let scriptHang = new TestHangReport(SLOW_SCRIPT);
+  let addonHang = new TestHangReport(ADDON_HANG);
+
+  [scriptHang, addonHang].forEach(hangReport => {
+    Services.obs.notifyObservers(hangReport, "process-hang-report");
+  });
+
+  // Quick and dirty hack to trick the window mediator into thinking there
+  // are no browser windows without actually closing all browser windows.
+  document.documentElement.setAttribute(
+    "windowtype",
+    "navigator:browsertestdummy"
+  );
+
+  // In case this test happens to throw before it can finish, make
+  // sure to reset this.
+  registerCleanupFunction(() => {
+    document.documentElement.setAttribute("windowtype", "navigator:browser");
+  });
+
+  await BrowserTestUtils.closeWindow(testWin);
+
+  let pausedAction = await pausedHang.promise;
+  let scriptAction = await scriptHang.promise;
+  let addonAction = await addonHang.promise;
+
+  is(
+    pausedAction,
+    TEST_ACTION_TERMSCRIPT,
+    "With no open windows, should have terminated script for paused script hang."
+  );
+  is(
+    scriptAction,
+    TEST_ACTION_TERMSCRIPT,
+    "With no open windows, should have terminated script for script hang."
+  );
+  is(
+    addonAction,
+    TEST_ACTION_TERMSCRIPT,
+    "With no open windows, should have terminated script for add-on hang."
+  );
+
+  // ProcessHangMonitor should notice we're in the "no windows" state,
+  // so any further hangs should be handled immediately without user
+  // interaction.
+  let scriptHang2 = new TestHangReport(SLOW_SCRIPT);
+  let addonHang2 = new TestHangReport(ADDON_HANG);
+
+  [scriptHang2, addonHang2].forEach(hangReport => {
+    Services.obs.notifyObservers(hangReport, "process-hang-report");
+  });
+
+  let scriptAction2 = await scriptHang.promise;
+  let addonAction2 = await addonHang.promise;
+
+  is(
+    scriptAction2,
+    TEST_ACTION_TERMSCRIPT,
+    "With no open windows, should have terminated script for script hang."
+  );
+  is(
+    addonAction2,
+    TEST_ACTION_TERMSCRIPT,
+    "With no open windows, should have terminated script for add-on hang."
+  );
+
+  document.documentElement.setAttribute("windowtype", "navigator:browser");
+});
+
+/**
+ * Test that if a script hang occurs in one browser window, and that
+ * browser window goes away, that we clear the hang. For plug-in hangs,
+ * we do the conservative thing and terminate any plug-in hangs when a
+ * window closes, even though we don't exactly know which window it
+ * belongs to.
+ */
+add_task(async function terminateClosedWindow() {
+  let testWin = await BrowserTestUtils.openNewBrowserWindow();
+  let testBrowser = testWin.gBrowser.selectedBrowser;
+
+  let pausedHang = new TestHangReport(SLOW_SCRIPT, testBrowser);
+  Services.obs.notifyObservers(pausedHang, "process-hang-report");
+  ProcessHangMonitor.waitLonger(testWin);
+  ok(
+    ProcessHangMonitor.findPausedReport(testWin.gBrowser.selectedBrowser),
+    "There should be a paused report for the selected browser."
+  );
+
+  let scriptHang = new TestHangReport(SLOW_SCRIPT, testBrowser);
+  let addonHang = new TestHangReport(ADDON_HANG, testBrowser);
+
+  [scriptHang, addonHang].forEach(hangReport => {
+    Services.obs.notifyObservers(hangReport, "process-hang-report");
+  });
+
+  await BrowserTestUtils.closeWindow(testWin);
+
+  let pausedAction = await pausedHang.promise;
+  let scriptAction = await scriptHang.promise;
+  let addonAction = await addonHang.promise;
+
+  is(
+    pausedAction,
+    TEST_ACTION_TERMSCRIPT,
+    "When closing window, should have terminated script for a paused script hang."
+  );
+  is(
+    scriptAction,
+    TEST_ACTION_TERMSCRIPT,
+    "When closing window, should have terminated script for script hang."
+  );
+  is(
+    addonAction,
+    TEST_ACTION_TERMSCRIPT,
+    "When closing window, should have terminated script for add-on hang."
+  );
+});
+
+/**
+ * Test that permitUnload (used for closing or discarding tabs) does not
+ * try to talk to the hung child
+ */
+add_task(async function permitUnload() {
+  let testWin = await BrowserTestUtils.openNewBrowserWindow();
+  let testTab = testWin.gBrowser.selectedTab;
+
+  // Ensure we don't close the window:
+  BrowserTestUtils.addTab(testWin.gBrowser, "about:blank");
+
+  // Set up the test tab and another tab so we can check what happens when
+  // they are closed:
+  let otherTab = BrowserTestUtils.addTab(testWin.gBrowser, "about:blank");
+  let permitUnloadCount = 0;
+  for (let tab of [testTab, otherTab]) {
+    let browser = tab.linkedBrowser;
+    // Fake before unload state:
+    Object.defineProperty(browser, "hasBeforeUnload", { value: true });
+    // Increment permitUnloadCount if we ask for unload permission:
+    browser.asyncPermitUnload = () => {
+      permitUnloadCount++;
+      return Promise.resolve({ permitUnload: true });
+    };
+  }
+
+  // Set up a hang for the selected tab:
+  let testBrowser = testTab.linkedBrowser;
+  let pausedHang = new TestHangReport(SLOW_SCRIPT, testBrowser);
+  Services.obs.notifyObservers(pausedHang, "process-hang-report");
+  ProcessHangMonitor.waitLonger(testWin);
+  ok(
+    ProcessHangMonitor.findPausedReport(testWin.gBrowser.selectedBrowser),
+    "There should be a paused report for the browser we're about to remove."
+  );
+
+  BrowserTestUtils.removeTab(otherTab);
+  BrowserTestUtils.removeTab(testWin.gBrowser.getTabForBrowser(testBrowser));
+  is(
+    permitUnloadCount,
+    1,
+    "Should have called asyncPermitUnload once (not for the hung tab)."
+  );
+
+  await BrowserTestUtils.closeWindow(testWin);
+});
diff --git a/browser/modules/test/browser/browser_SitePermissions.js b/browser/modules/test/browser/browser_SitePermissions.js
new file mode 100644
index 0000000000..d8542f8f85
--- /dev/null
+++ b/browser/modules/test/browser/browser_SitePermissions.js
@@ -0,0 +1,227 @@
+/* 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";
+
+// This tests the SitePermissions.getAllPermissionDetailsForBrowser function.
+add_task(async function testGetAllPermissionDetailsForBrowser() {
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    principal.spec
+  );
+
+  Services.prefs.setIntPref("permissions.default.shortcuts", 2);
+
+  let browser = tab.linkedBrowser;
+
+  SitePermissions.setForPrincipal(principal, "camera", SitePermissions.ALLOW);
+
+  SitePermissions.setForPrincipal(
+    principal,
+    "cookie",
+    SitePermissions.ALLOW_COOKIES_FOR_SESSION
+  );
+  SitePermissions.setForPrincipal(principal, "popup", SitePermissions.BLOCK);
+  SitePermissions.setForPrincipal(
+    principal,
+    "geo",
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_SESSION
+  );
+  SitePermissions.setForPrincipal(
+    principal,
+    "shortcuts",
+    SitePermissions.ALLOW
+  );
+
+  SitePermissions.setForPrincipal(principal, "xr", SitePermissions.ALLOW);
+
+  let permissions = SitePermissions.getAllPermissionDetailsForBrowser(browser);
+
+  let camera = permissions.find(({ id }) => id === "camera");
+  Assert.deepEqual(camera, {
+    id: "camera",
+    label: "Use the camera",
+    state: SitePermissions.ALLOW,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // Check that removed permissions (State.UNKNOWN) are skipped.
+  SitePermissions.removeFromPrincipal(principal, "camera");
+  permissions = SitePermissions.getAllPermissionDetailsForBrowser(browser);
+
+  camera = permissions.find(({ id }) => id === "camera");
+  Assert.equal(camera, undefined);
+
+  let cookie = permissions.find(({ id }) => id === "cookie");
+  Assert.deepEqual(cookie, {
+    id: "cookie",
+    label: "Set cookies",
+    state: SitePermissions.ALLOW_COOKIES_FOR_SESSION,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  let popup = permissions.find(({ id }) => id === "popup");
+  Assert.deepEqual(popup, {
+    id: "popup",
+    label: "Open pop-up windows",
+    state: SitePermissions.BLOCK,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  let geo = permissions.find(({ id }) => id === "geo");
+  Assert.deepEqual(geo, {
+    id: "geo",
+    label: "Access your location",
+    state: SitePermissions.ALLOW,
+    scope: SitePermissions.SCOPE_SESSION,
+  });
+
+  let shortcuts = permissions.find(({ id }) => id === "shortcuts");
+  Assert.deepEqual(shortcuts, {
+    id: "shortcuts",
+    label: "Override keyboard shortcuts",
+    state: SitePermissions.ALLOW,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  let xr = permissions.find(({ id }) => id === "xr");
+  Assert.deepEqual(xr, {
+    id: "xr",
+    label: "Access virtual reality devices",
+    state: SitePermissions.ALLOW,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  SitePermissions.removeFromPrincipal(principal, "cookie");
+  SitePermissions.removeFromPrincipal(principal, "popup");
+  SitePermissions.removeFromPrincipal(principal, "geo");
+  SitePermissions.removeFromPrincipal(principal, "shortcuts");
+
+  SitePermissions.removeFromPrincipal(principal, "xr");
+
+  Services.prefs.clearUserPref("permissions.default.shortcuts");
+
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});
+
+add_task(async function testTemporaryChangeEvent() {
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    principal.spec
+  );
+
+  let browser = tab.linkedBrowser;
+
+  let changeEventCount = 0;
+  function listener() {
+    changeEventCount++;
+  }
+
+  browser.addEventListener("PermissionStateChange", listener);
+
+  // Test browser-specific permissions.
+  SitePermissions.setForPrincipal(
+    browser.contentPrincipal,
+    "autoplay-media",
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_GLOBAL,
+    browser
+  );
+  is(changeEventCount, 1, "Should've changed");
+
+  // Setting the same value shouldn't dispatch a change event.
+  SitePermissions.setForPrincipal(
+    browser.contentPrincipal,
+    "autoplay-media",
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_GLOBAL,
+    browser
+  );
+  is(changeEventCount, 1, "Shouldn't have changed");
+
+  browser.removeEventListener("PermissionStateChange", listener);
+
+  BrowserTestUtils.removeTab(tab);
+});
+
+add_task(async function testInvalidPrincipal() {
+  // Check that an error is thrown when an invalid principal argument is passed.
+  try {
+    SitePermissions.isSupportedPrincipal("file:///example.js");
+  } catch (e) {
+    Assert.equal(
+      e.message,
+      "Argument passed as principal is not an instance of Ci.nsIPrincipal"
+    );
+  }
+  try {
+    SitePermissions.removeFromPrincipal(null, "canvas");
+  } catch (e) {
+    Assert.equal(
+      e.message,
+      "Atleast one of the arguments, either principal or browser should not be null."
+    );
+  }
+  try {
+    SitePermissions.setForPrincipal(
+      "blah",
+      "camera",
+      SitePermissions.ALLOW,
+      SitePermissions.SCOPE_PERSISTENT,
+      gBrowser.selectedBrowser
+    );
+  } catch (e) {
+    Assert.equal(
+      e.message,
+      "Argument passed as principal is not an instance of Ci.nsIPrincipal"
+    );
+  }
+  try {
+    SitePermissions.getAllByPrincipal("blah");
+  } catch (e) {
+    Assert.equal(
+      e.message,
+      "Argument passed as principal is not an instance of Ci.nsIPrincipal"
+    );
+  }
+  try {
+    SitePermissions.getAllByPrincipal(null);
+  } catch (e) {
+    Assert.equal(e.message, "principal argument cannot be null.");
+  }
+  try {
+    SitePermissions.getForPrincipal(5, "camera");
+  } catch (e) {
+    Assert.equal(
+      e.message,
+      "Argument passed as principal is not an instance of Ci.nsIPrincipal"
+    );
+  }
+  // Check that no error is thrown when passing valid principal and browser arguments.
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(gBrowser.contentPrincipal, "camera"),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    }
+  );
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, "camera", gBrowser.selectedBrowser),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    }
+  );
+});
diff --git a/browser/modules/test/browser/browser_SitePermissions_combinations.js b/browser/modules/test/browser/browser_SitePermissions_combinations.js
new file mode 100644
index 0000000000..e6267f72cc
--- /dev/null
+++ b/browser/modules/test/browser/browser_SitePermissions_combinations.js
@@ -0,0 +1,144 @@
+/* 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";
+
+// This function applies combinations of different permissions and
+// checks how they override each other.
+async function checkPermissionCombinations(combinations) {
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+
+  await BrowserTestUtils.withNewTab(principal.spec, function (browser) {
+    let id = "geo";
+    for (let { reverse, states, result } of combinations) {
+      let loop = () => {
+        for (let [state, scope] of states) {
+          SitePermissions.setForPrincipal(principal, id, state, scope, browser);
+        }
+        Assert.deepEqual(
+          SitePermissions.getForPrincipal(principal, id, browser),
+          result
+        );
+        SitePermissions.removeFromPrincipal(principal, id, browser);
+      };
+
+      loop();
+
+      if (reverse) {
+        states.reverse();
+        loop();
+      }
+    }
+  });
+}
+
+// Test that passing null as scope becomes SCOPE_PERSISTENT.
+add_task(async function testDefaultScope() {
+  await checkPermissionCombinations([
+    {
+      states: [[SitePermissions.ALLOW, null]],
+      result: {
+        state: SitePermissions.ALLOW,
+        scope: SitePermissions.SCOPE_PERSISTENT,
+      },
+    },
+  ]);
+});
+
+// Test that "wide" scopes like PERSISTENT always override "narrower" ones like TAB.
+add_task(async function testScopeOverrides() {
+  await checkPermissionCombinations([
+    {
+      // The behavior of SCOPE_SESSION is not in line with the general behavior
+      // because of the legacy nsIPermissionManager implementation.
+      states: [
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_PERSISTENT],
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_SESSION],
+      ],
+      result: {
+        state: SitePermissions.BLOCK,
+        scope: SitePermissions.SCOPE_SESSION,
+      },
+    },
+    {
+      states: [
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_SESSION],
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_PERSISTENT],
+      ],
+      result: {
+        state: SitePermissions.ALLOW,
+        scope: SitePermissions.SCOPE_PERSISTENT,
+      },
+    },
+    {
+      reverse: true,
+      states: [
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_TEMPORARY],
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_SESSION],
+      ],
+      result: {
+        state: SitePermissions.ALLOW,
+        scope: SitePermissions.SCOPE_SESSION,
+      },
+    },
+    {
+      reverse: true,
+      states: [
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_TEMPORARY],
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_PERSISTENT],
+      ],
+      result: {
+        state: SitePermissions.ALLOW,
+        scope: SitePermissions.SCOPE_PERSISTENT,
+      },
+    },
+  ]);
+});
+
+// Test that clearing a temporary permission also removes a
+// persistent permission that was set for the same URL.
+add_task(async function testClearTempPermission() {
+  await checkPermissionCombinations([
+    {
+      states: [
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_TEMPORARY],
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_PERSISTENT],
+        [SitePermissions.UNKNOWN, SitePermissions.SCOPE_TEMPORARY],
+      ],
+      result: {
+        state: SitePermissions.UNKNOWN,
+        scope: SitePermissions.SCOPE_PERSISTENT,
+      },
+    },
+  ]);
+});
+
+// Test that states override each other when applied with the same scope.
+add_task(async function testStateOverride() {
+  await checkPermissionCombinations([
+    {
+      states: [
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_PERSISTENT],
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_PERSISTENT],
+      ],
+      result: {
+        state: SitePermissions.BLOCK,
+        scope: SitePermissions.SCOPE_PERSISTENT,
+      },
+    },
+    {
+      states: [
+        [SitePermissions.BLOCK, SitePermissions.SCOPE_PERSISTENT],
+        [SitePermissions.ALLOW, SitePermissions.SCOPE_PERSISTENT],
+      ],
+      result: {
+        state: SitePermissions.ALLOW,
+        scope: SitePermissions.SCOPE_PERSISTENT,
+      },
+    },
+  ]);
+});
diff --git a/browser/modules/test/browser/browser_SitePermissions_expiry.js b/browser/modules/test/browser/browser_SitePermissions_expiry.js
new file mode 100644
index 0000000000..c5806a8008
--- /dev/null
+++ b/browser/modules/test/browser/browser_SitePermissions_expiry.js
@@ -0,0 +1,44 @@
+/* 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/. */
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+
+"use strict";
+
+const EXPIRE_TIME_MS = 100;
+const TIMEOUT_MS = 500;
+
+// This tests the time delay to expire temporary permission entries.
+add_task(async function testTemporaryPermissionExpiry() {
+  SpecialPowers.pushPrefEnv({
+    set: [["privacy.temporary_permission_expire_time_ms", EXPIRE_TIME_MS]],
+  });
+
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+  let id = "camera";
+
+  await BrowserTestUtils.withNewTab(principal.spec, async function (browser) {
+    SitePermissions.setForPrincipal(
+      principal,
+      id,
+      SitePermissions.BLOCK,
+      SitePermissions.SCOPE_TEMPORARY,
+      browser
+    );
+
+    Assert.deepEqual(SitePermissions.getForPrincipal(principal, id, browser), {
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    });
+
+    await new Promise(c => setTimeout(c, TIMEOUT_MS));
+
+    Assert.deepEqual(SitePermissions.getForPrincipal(principal, id, browser), {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    });
+  });
+});
diff --git a/browser/modules/test/browser/browser_SitePermissions_tab_urls.js b/browser/modules/test/browser/browser_SitePermissions_tab_urls.js
new file mode 100644
index 0000000000..f259486282
--- /dev/null
+++ b/browser/modules/test/browser/browser_SitePermissions_tab_urls.js
@@ -0,0 +1,128 @@
+/* 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";
+
+function newPrincipal(origin) {
+  return Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+    origin
+  );
+}
+
+// This tests the key used to store the URI -> permission map on a tab.
+add_task(async function testTemporaryPermissionTabURLs() {
+  // Prevent showing a dialog for https://name:password@example.com
+  SpecialPowers.pushPrefEnv({
+    set: [["network.http.phishy-userpass-length", 2048]],
+  });
+
+  // This usually takes about 60 seconds on 32bit Linux debug,
+  // due to the combinatory nature of the test that is hard to fix.
+  requestLongerTimeout(2);
+
+  let same = [
+    newPrincipal("https://example.com"),
+    newPrincipal("https://example.com:443"),
+    newPrincipal("https://test1.example.com"),
+    newPrincipal("https://name:password@example.com"),
+    newPrincipal("http://example.com"),
+  ];
+  let different = [
+    newPrincipal("https://example.com"),
+    newPrincipal("http://example.org"),
+    newPrincipal("http://example.net"),
+  ];
+
+  let id = "microphone";
+
+  await BrowserTestUtils.withNewTab("about:blank", async function (browser) {
+    for (let principal of same) {
+      let loaded = BrowserTestUtils.browserLoaded(
+        browser,
+        false,
+        principal.spec
+      );
+      BrowserTestUtils.startLoadingURIString(browser, principal.spec);
+      await loaded;
+
+      SitePermissions.setForPrincipal(
+        principal,
+        id,
+        SitePermissions.BLOCK,
+        SitePermissions.SCOPE_TEMPORARY,
+        browser
+      );
+
+      for (let principal2 of same) {
+        let loaded2 = BrowserTestUtils.browserLoaded(
+          browser,
+          false,
+          principal2.URI.spec
+        );
+        BrowserTestUtils.startLoadingURIString(browser, principal2.URI.spec);
+        await loaded2;
+
+        Assert.deepEqual(
+          SitePermissions.getForPrincipal(principal2, id, browser),
+          {
+            state: SitePermissions.BLOCK,
+            scope: SitePermissions.SCOPE_TEMPORARY,
+          },
+          `${principal.spec} should share tab permissions with ${principal2.spec}`
+        );
+      }
+
+      SitePermissions.clearTemporaryBlockPermissions(browser);
+    }
+
+    for (let principal of different) {
+      let loaded = BrowserTestUtils.browserLoaded(
+        browser,
+        false,
+        principal.spec
+      );
+      BrowserTestUtils.startLoadingURIString(browser, principal.spec);
+      await loaded;
+
+      SitePermissions.setForPrincipal(
+        principal,
+        id,
+        SitePermissions.BLOCK,
+        SitePermissions.SCOPE_TEMPORARY,
+        browser
+      );
+
+      Assert.deepEqual(
+        SitePermissions.getForPrincipal(principal, id, browser),
+        {
+          state: SitePermissions.BLOCK,
+          scope: SitePermissions.SCOPE_TEMPORARY,
+        }
+      );
+
+      for (let principal2 of different) {
+        loaded = BrowserTestUtils.browserLoaded(
+          browser,
+          false,
+          principal2.URI.spec
+        );
+        BrowserTestUtils.startLoadingURIString(browser, principal2.URI.spec);
+        await loaded;
+
+        if (principal2 != principal) {
+          Assert.deepEqual(
+            SitePermissions.getForPrincipal(principal2, id, browser),
+            {
+              state: SitePermissions.UNKNOWN,
+              scope: SitePermissions.SCOPE_PERSISTENT,
+            },
+            `${principal.spec} should not share tab permissions with ${principal2.spec}`
+          );
+        }
+      }
+
+      SitePermissions.clearTemporaryBlockPermissions(browser);
+    }
+  });
+});
diff --git a/browser/modules/test/browser/browser_TabUnloader.js b/browser/modules/test/browser/browser_TabUnloader.js
new file mode 100644
index 0000000000..d564abb620
--- /dev/null
+++ b/browser/modules/test/browser/browser_TabUnloader.js
@@ -0,0 +1,381 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const { TabUnloader } = ChromeUtils.importESModule(
+  "resource:///modules/TabUnloader.sys.mjs"
+);
+
+const BASE_URL = "https://example.com/browser/browser/modules/test/browser/";
+
+async function play(tab) {
+  let browser = tab.linkedBrowser;
+
+  let waitForAudioPromise = BrowserTestUtils.waitForEvent(
+    tab,
+    "TabAttrModified",
+    false,
+    event => {
+      return (
+        event.detail.changed.includes("soundplaying") &&
+        tab.hasAttribute("soundplaying")
+      );
+    }
+  );
+
+  await SpecialPowers.spawn(browser, [], async function () {
+    let audio = content.document.querySelector("audio");
+    await audio.play();
+  });
+
+  await waitForAudioPromise;
+}
+
+async function addTab(win = window) {
+  return BrowserTestUtils.openNewForegroundTab({
+    gBrowser: win.gBrowser,
+    url: BASE_URL + "dummy_page.html",
+    waitForLoad: true,
+  });
+}
+
+async function addPrivTab(win = window) {
+  const tab = BrowserTestUtils.addTab(
+    win.gBrowser,
+    BASE_URL + "dummy_page.html"
+  );
+  const browser = win.gBrowser.getBrowserForTab(tab);
+  await BrowserTestUtils.browserLoaded(browser);
+  return tab;
+}
+
+async function addAudioTab(win = window) {
+  let tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser: win.gBrowser,
+    url: BASE_URL + "file_mediaPlayback.html",
+    waitForLoad: true,
+    waitForStateStop: true,
+  });
+
+  await play(tab);
+  return tab;
+}
+
+async function addWebRTCTab(win = window) {
+  let popupPromise = new Promise(resolve => {
+    win.PopupNotifications.panel.addEventListener(
+      "popupshown",
+      function () {
+        executeSoon(resolve);
+      },
+      { once: true }
+    );
+  });
+
+  let tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser: win.gBrowser,
+    url: BASE_URL + "file_webrtc.html",
+    waitForLoad: true,
+    waitForStateStop: true,
+  });
+
+  await popupPromise;
+
+  let recordingPromise = BrowserTestUtils.contentTopicObserved(
+    tab.linkedBrowser.browsingContext,
+    "recording-device-events"
+  );
+  win.PopupNotifications.panel.firstElementChild.button.click();
+  await recordingPromise;
+
+  return tab;
+}
+
+async function pressure() {
+  let tabDiscarded = BrowserTestUtils.waitForEvent(
+    document,
+    "TabBrowserDiscarded",
+    true
+  );
+  TabUnloader.unloadTabAsync(null);
+  return tabDiscarded;
+}
+
+function pressureAndObserve(aExpectedTopic) {
+  const promise = new Promise(resolve => {
+    const observer = {
+      QueryInterface: ChromeUtils.generateQI([
+        "nsIObserver",
+        "nsISupportsWeakReference",
+      ]),
+      observe(aSubject, aTopicInner, aData) {
+        if (aTopicInner == aExpectedTopic) {
+          Services.obs.removeObserver(observer, aTopicInner);
+          resolve(aData);
+        }
+      },
+    };
+    Services.obs.addObserver(observer, aExpectedTopic);
+  });
+  TabUnloader.unloadTabAsync(null);
+  return promise;
+}
+
+async function compareTabOrder(expectedOrder) {
+  let tabInfo = await TabUnloader.getSortedTabs(null);
+
+  is(
+    tabInfo.length,
+    expectedOrder.length,
+    "right number of tabs in discard sort list"
+  );
+  for (let idx = 0; idx < expectedOrder.length; idx++) {
+    is(tabInfo[idx].tab, expectedOrder[idx], "index " + idx + " is correct");
+  }
+}
+
+const PREF_PERMISSION_FAKE = "media.navigator.permission.fake";
+const PREF_AUDIO_LOOPBACK = "media.audio_loopback_dev";
+const PREF_VIDEO_LOOPBACK = "media.video_loopback_dev";
+const PREF_FAKE_STREAMS = "media.navigator.streams.fake";
+const PREF_ENABLE_UNLOADER = "browser.tabs.unloadOnLowMemory";
+const PREF_MAC_LOW_MEM_RESPONSE = "browser.lowMemoryResponseMask";
+
+add_task(async function test() {
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref(PREF_ENABLE_UNLOADER);
+    if (AppConstants.platform == "macosx") {
+      Services.prefs.clearUserPref(PREF_MAC_LOW_MEM_RESPONSE);
+    }
+  });
+  Services.prefs.setBoolPref(PREF_ENABLE_UNLOADER, true);
+
+  // On Mac, tab unloading and memory pressure notifications are limited
+  // to Nightly so force them on for this test for non-Nightly builds. i.e.,
+  // tests on Release and Beta builds. Mac tab unloading and memory pressure
+  // notifications require this pref to be set.
+  if (AppConstants.platform == "macosx") {
+    Services.prefs.setIntPref(PREF_MAC_LOW_MEM_RESPONSE, 3);
+  }
+
+  TabUnloader.init();
+
+  // Set some WebRTC simulation preferences.
+  let prefs = [
+    [PREF_PERMISSION_FAKE, true],
+    [PREF_AUDIO_LOOPBACK, ""],
+    [PREF_VIDEO_LOOPBACK, ""],
+    [PREF_FAKE_STREAMS, true],
+  ];
+  await SpecialPowers.pushPrefEnv({ set: prefs });
+
+  // Set up 6 tabs, three normal ones, one pinned, one playing sound and one
+  // pinned playing sound
+  let tab0 = gBrowser.tabs[0];
+  let tab1 = await addTab();
+  let tab2 = await addTab();
+  let pinnedTab = await addTab();
+  gBrowser.pinTab(pinnedTab);
+  let soundTab = await addAudioTab();
+  let pinnedSoundTab = await addAudioTab();
+  gBrowser.pinTab(pinnedSoundTab);
+
+  // Open a new private window and add a tab
+  const windowPriv = await BrowserTestUtils.openNewBrowserWindow({
+    private: true,
+  });
+  const tabPriv0 = windowPriv.gBrowser.tabs[0];
+  const tabPriv1 = await addPrivTab(windowPriv);
+
+  // Move the original window to the foreground to pass the tests
+  gBrowser.selectedTab = tab0;
+  tab0.ownerGlobal.focus();
+
+  // Pretend we've visited the tabs
+  await BrowserTestUtils.switchTab(windowPriv.gBrowser, tabPriv1);
+  await BrowserTestUtils.switchTab(windowPriv.gBrowser, tabPriv0);
+  await BrowserTestUtils.switchTab(gBrowser, tab1);
+  await BrowserTestUtils.switchTab(gBrowser, tab2);
+  await BrowserTestUtils.switchTab(gBrowser, pinnedTab);
+  await BrowserTestUtils.switchTab(gBrowser, soundTab);
+  await BrowserTestUtils.switchTab(gBrowser, pinnedSoundTab);
+  await BrowserTestUtils.switchTab(gBrowser, tab0);
+
+  // Checks the tabs are in the state we expect them to be
+  ok(pinnedTab.pinned, "tab is pinned");
+  ok(pinnedSoundTab.soundPlaying, "tab is playing sound");
+  ok(
+    pinnedSoundTab.pinned && pinnedSoundTab.soundPlaying,
+    "tab is pinned and playing sound"
+  );
+
+  await compareTabOrder([
+    tab1,
+    tab2,
+    pinnedTab,
+    tabPriv1,
+    soundTab,
+    tab0,
+    pinnedSoundTab,
+    tabPriv0,
+  ]);
+
+  // Check that the tabs are present
+  ok(
+    tab1.linkedPanel &&
+      tab2.linkedPanel &&
+      pinnedTab.linkedPanel &&
+      soundTab.linkedPanel &&
+      pinnedSoundTab.linkedPanel &&
+      tabPriv0.linkedPanel &&
+      tabPriv1.linkedPanel,
+    "tabs are present"
+  );
+
+  // Check that low-memory memory-pressure events unload tabs
+  await pressure();
+  ok(
+    !tab1.linkedPanel,
+    "low-memory memory-pressure notification unloaded the LRU tab"
+  );
+
+  await compareTabOrder([
+    tab2,
+    pinnedTab,
+    tabPriv1,
+    soundTab,
+    tab0,
+    pinnedSoundTab,
+    tabPriv0,
+  ]);
+
+  // If no normal tab is available unload pinned tabs
+  await pressure();
+  ok(!tab2.linkedPanel, "unloaded a second tab in LRU order");
+  await compareTabOrder([
+    pinnedTab,
+    tabPriv1,
+    soundTab,
+    tab0,
+    pinnedSoundTab,
+    tabPriv0,
+  ]);
+
+  ok(soundTab.soundPlaying, "tab is still playing sound");
+
+  await pressure();
+  ok(!pinnedTab.linkedPanel, "unloaded a pinned tab");
+  await compareTabOrder([tabPriv1, soundTab, tab0, pinnedSoundTab, tabPriv0]);
+
+  ok(pinnedSoundTab.soundPlaying, "tab is still playing sound");
+
+  // There are no unloadable tabs.
+  TabUnloader.unloadTabAsync(null);
+  ok(tabPriv1.linkedPanel, "a tab in a private window is never unloaded");
+
+  const histogram = TelemetryTestUtils.getAndClearHistogram(
+    "TAB_UNLOAD_TO_RELOAD"
+  );
+
+  // It's possible that we're already in the memory-pressure state
+  // and we may receive the "ongoing" message.
+  const message = await pressureAndObserve("memory-pressure");
+  Assert.ok(
+    message == "low-memory" || message == "low-memory-ongoing",
+    "observed the memory-pressure notification because of no discardable tab"
+  );
+
+  // Add a WebRTC tab and another sound tab.
+  let webrtcTab = await addWebRTCTab();
+  let anotherSoundTab = await addAudioTab();
+
+  await BrowserTestUtils.switchTab(gBrowser, tab1);
+  await BrowserTestUtils.switchTab(gBrowser, pinnedTab);
+
+  const hist = histogram.snapshot();
+  const numEvents = Object.values(hist.values).reduce((a, b) => a + b);
+  Assert.equal(numEvents, 2, "two tabs have been reloaded.");
+
+  // tab0 has never been unloaded.  No data is added to the histogram.
+  await BrowserTestUtils.switchTab(gBrowser, tab0);
+
+  await compareTabOrder([
+    tab1,
+    pinnedTab,
+    tabPriv1,
+    soundTab,
+    webrtcTab,
+    anotherSoundTab,
+    tab0,
+    pinnedSoundTab,
+    tabPriv0,
+  ]);
+
+  await BrowserTestUtils.closeWindow(windowPriv);
+
+  let window2 = await BrowserTestUtils.openNewBrowserWindow();
+  let win2tab1 = window2.gBrowser.selectedTab;
+  let win2tab2 = await addTab(window2);
+  let win2winrtcTab = await addWebRTCTab(window2);
+  let win2tab3 = await addTab(window2);
+
+  await compareTabOrder([
+    tab1,
+    win2tab1,
+    win2tab2,
+    pinnedTab,
+    soundTab,
+    webrtcTab,
+    anotherSoundTab,
+    win2winrtcTab,
+    tab0,
+    win2tab3,
+    pinnedSoundTab,
+  ]);
+
+  await BrowserTestUtils.closeWindow(window2);
+
+  await compareTabOrder([
+    tab1,
+    pinnedTab,
+    soundTab,
+    webrtcTab,
+    anotherSoundTab,
+    tab0,
+    pinnedSoundTab,
+  ]);
+
+  // Cleanup
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+  BrowserTestUtils.removeTab(pinnedTab);
+  BrowserTestUtils.removeTab(soundTab);
+  BrowserTestUtils.removeTab(pinnedSoundTab);
+  BrowserTestUtils.removeTab(webrtcTab);
+  BrowserTestUtils.removeTab(anotherSoundTab);
+
+  await awaitWebRTCClose();
+});
+
+// Wait for the WebRTC indicator window to close.
+function awaitWebRTCClose() {
+  if (
+    Services.prefs.getBoolPref("privacy.webrtc.legacyGlobalIndicator", false) ||
+    AppConstants.platform == "macosx"
+  ) {
+    return null;
+  }
+
+  let win = Services.wm.getMostRecentWindow("Browser:WebRTCGlobalIndicator");
+  if (!win) {
+    return null;
+  }
+
+  return new Promise(resolve => {
+    win.addEventListener("unload", function listener(e) {
+      if (e.target == win.document) {
+        win.removeEventListener("unload", listener);
+        executeSoon(resolve);
+      }
+    });
+  });
+}
diff --git a/browser/modules/test/browser/browser_Telemetry_numberOfSiteOrigins.js b/browser/modules/test/browser/browser_Telemetry_numberOfSiteOrigins.js
new file mode 100644
index 0000000000..9ce5602eda
--- /dev/null
+++ b/browser/modules/test/browser/browser_Telemetry_numberOfSiteOrigins.js
@@ -0,0 +1,53 @@
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+/**
+ * This file tests page reload key combination telemetry
+ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+});
+
+const gTestRoot = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://mochi.test:8888"
+);
+
+const { TimedPromise } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/sync.sys.mjs"
+);
+
+async function run_test(count) {
+  const histogram = TelemetryTestUtils.getAndClearHistogram(
+    "FX_NUMBER_OF_UNIQUE_SITE_ORIGINS_ALL_TABS"
+  );
+
+  let newTab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    opening: gTestRoot + "contain_iframe.html",
+    waitForStateStop: true,
+  });
+
+  await new Promise(resolve =>
+    setTimeout(function () {
+      window.requestIdleCallback(resolve);
+    }, 1000)
+  );
+
+  if (count < 2) {
+    await BrowserTestUtils.removeTab(newTab);
+    await run_test(count + 1);
+  } else {
+    TelemetryTestUtils.assertHistogram(histogram, 2, 1);
+    await BrowserTestUtils.removeTab(newTab);
+  }
+}
+
+add_task(async function test_telemetryMoreSiteOrigin() {
+  await run_test(1);
+});
diff --git a/browser/modules/test/browser/browser_Telemetry_numberOfSiteOriginsPerDocument.js b/browser/modules/test/browser/browser_Telemetry_numberOfSiteOriginsPerDocument.js
new file mode 100644
index 0000000000..d60660960f
--- /dev/null
+++ b/browser/modules/test/browser/browser_Telemetry_numberOfSiteOriginsPerDocument.js
@@ -0,0 +1,134 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+});
+
+const histogramName = "FX_NUMBER_OF_UNIQUE_SITE_ORIGINS_PER_DOCUMENT";
+const testRoot = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://mochi.test:8888"
+);
+
+function windowGlobalDestroyed(id) {
+  return BrowserUtils.promiseObserved(
+    "window-global-destroyed",
+    aWGP => aWGP.innerWindowId == id
+  );
+}
+
+async function openAndCloseTab(uri) {
+  const tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    opening: uri,
+  });
+
+  const innerWindowId =
+    tab.linkedBrowser.browsingContext.currentWindowGlobal.innerWindowId;
+
+  const wgpDestroyed = windowGlobalDestroyed(innerWindowId);
+  BrowserTestUtils.removeTab(tab);
+  await wgpDestroyed;
+}
+
+add_task(async function test_numberOfSiteOriginsAfterTabClose() {
+  const histogram = TelemetryTestUtils.getAndClearHistogram(histogramName);
+  const testPage = `${testRoot}contain_iframe.html`;
+
+  await openAndCloseTab(testPage);
+
+  // testPage contains two origins: mochi.test:8888 and example.com.
+  TelemetryTestUtils.assertHistogram(histogram, 2, 1);
+});
+
+add_task(async function test_numberOfSiteOriginsAboutBlank() {
+  const histogram = TelemetryTestUtils.getAndClearHistogram(histogramName);
+
+  await openAndCloseTab("about:blank");
+
+  const { values } = histogram.snapshot();
+  Assert.deepEqual(
+    values,
+    {},
+    `Histogram should have no values; had ${JSON.stringify(values)}`
+  );
+});
+
+add_task(async function test_numberOfSiteOriginsMultipleNavigations() {
+  const histogram = TelemetryTestUtils.getAndClearHistogram(histogramName);
+  const testPage = `${testRoot}contain_iframe.html`;
+
+  const tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    opening: testPage,
+    waitForStateStop: true,
+  });
+
+  const wgpDestroyedPromises = [
+    windowGlobalDestroyed(tab.linkedBrowser.innerWindowID),
+  ];
+
+  // Navigate to an interstitial page.
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, "about:blank");
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);
+
+  // Navigate to another test page.
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, testPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);
+
+  wgpDestroyedPromises.push(
+    windowGlobalDestroyed(tab.linkedBrowser.innerWindowID)
+  );
+
+  BrowserTestUtils.removeTab(tab);
+  await Promise.all(wgpDestroyedPromises);
+
+  // testPage has been loaded twice and contains two origins: mochi.test:8888
+  // and example.com.
+  TelemetryTestUtils.assertHistogram(histogram, 2, 2);
+});
+
+add_task(async function test_numberOfSiteOriginsAddAndRemove() {
+  const histogram = TelemetryTestUtils.getAndClearHistogram(histogramName);
+  const testPage = `${testRoot}blank_iframe.html`;
+
+  const tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    opening: testPage,
+    waitForStateStop: true,
+  });
+
+  // Load a subdocument in the page's iframe.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    const iframe = content.window.document.querySelector("iframe");
+    const loaded = new Promise(resolve => {
+      iframe.addEventListener("load", () => resolve(), { once: true });
+    });
+    iframe.src = "http://example.com";
+
+    await loaded;
+  });
+
+  // Load a *new* subdocument in the page's iframe. This will result in the page
+  // having had three different origins, but only two at any one time.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    const iframe = content.window.document.querySelector("iframe");
+    const loaded = new Promise(resolve => {
+      iframe.addEventListener("load", () => resolve(), { once: true });
+    });
+    iframe.src = "http://example.org";
+
+    await loaded;
+  });
+
+  const wgpDestroyed = windowGlobalDestroyed(tab.linkedBrowser.innerWindowID);
+  BrowserTestUtils.removeTab(tab);
+  await wgpDestroyed;
+
+  // The page only ever had two origins at once.
+  TelemetryTestUtils.assertHistogram(histogram, 2, 1);
+});
diff --git a/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js b/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
new file mode 100644
index 0000000000..4305d7f7df
--- /dev/null
+++ b/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
@@ -0,0 +1,815 @@
+"use strict";
+
+/**
+ * This suite tests the "unsubmitted crash report" notification
+ * that is seen when we detect pending crash reports on startup.
+ */
+
+const { UnsubmittedCrashHandler } = ChromeUtils.importESModule(
+  "resource:///modules/ContentCrashHandlers.sys.mjs"
+);
+
+const { makeFakeAppDir } = ChromeUtils.importESModule(
+  "resource://testing-common/AppData.sys.mjs"
+);
+
+const DAY = 24 * 60 * 60 * 1000; // milliseconds
+const SERVER_URL =
+  "http://example.com/browser/toolkit/crashreporter/test/browser/crashreport.sjs";
+
+/**
+ * Returns the directly where the browsing is storing the
+ * pending crash reports.
+ *
+ * @returns nsIFile
+ */
+function getPendingCrashReportDir() {
+  // The fake UAppData directory that makeFakeAppDir provides
+  // is just UAppData under the profile directory.
+  return FileUtils.getDir("ProfD", ["UAppData", "Crash Reports", "pending"]);
+}
+
+/**
+ * Synchronously deletes all entries inside the pending
+ * crash report directory.
+ */
+function clearPendingCrashReports() {
+  let dir = getPendingCrashReportDir();
+  let entries = dir.directoryEntries;
+
+  while (entries.hasMoreElements()) {
+    let entry = entries.nextFile;
+    if (entry.isFile()) {
+      entry.remove(false);
+    }
+  }
+}
+
+/**
+ * Randomly generates howMany crash report .dmp and .extra files
+ * to put into the pending crash report directory. We're not
+ * actually creating real crash reports here, just stubbing
+ * out enough of the files to satisfy our notification and
+ * submission code.
+ *
+ * @param howMany (int)
+ *        How many pending crash reports to put in the pending
+ *        crash report directory.
+ * @param accessDate (Date, optional)
+ *        What date to set as the last accessed time on the created
+ *        crash reports. This defaults to the current date and time.
+ * @returns Promise
+ */
+function createPendingCrashReports(howMany, accessDate) {
+  let dir = getPendingCrashReportDir();
+  if (!accessDate) {
+    accessDate = new Date();
+  }
+
+  /**
+   * Helper function for creating a file in the pending crash report
+   * directory.
+   *
+   * @param fileName (string)
+   *        The filename for the crash report, not including the
+   *        extension. This is usually a UUID.
+   * @param extension (string)
+   *        The file extension for the created file.
+   * @param accessDate (Date, optional)
+   *        The date to set lastAccessed to, if anything.
+   * @param contents (string, optional)
+   *        Set this to whatever the file needs to contain, if anything.
+   * @returns Promise
+   */
+  let createFile = async (fileName, extension, lastAccessedDate, contents) => {
+    let file = dir.clone();
+    file.append(fileName + "." + extension);
+    file.create(Ci.nsIFile.NORMAL_FILE_TYPE, FileUtils.PERMS_FILE);
+
+    if (contents) {
+      await IOUtils.writeUTF8(file.path, contents, {
+        tmpPath: file.path + ".tmp",
+      });
+    }
+
+    if (lastAccessedDate) {
+      await IOUtils.setAccessTime(file.path, lastAccessedDate.valueOf());
+    }
+  };
+
+  let uuidGenerator = Services.uuid;
+  // Some annotations are always present in the .extra file and CrashSubmit.jsm
+  // expects there to be a ServerURL entry, so we'll add them here.
+  let extraFileContents = JSON.stringify({
+    ServerURL: SERVER_URL,
+    TelemetryServerURL: "http://telemetry.mozilla.org/",
+    TelemetryClientId: "c69e7487-df10-4c98-ab1a-c85660feecf3",
+    TelemetrySessionId: "22af5a41-6e84-4112-b1f7-4cb12cb6f6a5",
+  });
+
+  return (async function () {
+    let uuids = [];
+    for (let i = 0; i < howMany; ++i) {
+      let uuid = uuidGenerator.generateUUID().toString();
+      // Strip the {}...
+      uuid = uuid.substring(1, uuid.length - 1);
+      await createFile(uuid, "dmp", accessDate);
+      await createFile(uuid, "extra", accessDate, extraFileContents);
+      uuids.push(uuid);
+    }
+    return uuids;
+  })();
+}
+
+/**
+ * Returns a Promise that resolves once CrashSubmit starts sending
+ * success notifications for crash submission matching the reportIDs
+ * being passed in.
+ *
+ * @param reportIDs (Array<string>)
+ *        The IDs for the reports that we expect CrashSubmit to have sent.
+ * @param extraCheck (Function, optional)
+ *        A function that receives the annotations of the crash report and can
+ *        be used for checking them
+ * @returns Promise
+ */
+function waitForSubmittedReports(reportIDs, extraCheck) {
+  let promises = [];
+  for (let reportID of reportIDs) {
+    let promise = TestUtils.topicObserved(
+      "crash-report-status",
+      (subject, data) => {
+        if (data == "success") {
+          let propBag = subject.QueryInterface(Ci.nsIPropertyBag2);
+          let dumpID = propBag.getPropertyAsAString("minidumpID");
+          if (dumpID == reportID) {
+            if (extraCheck) {
+              let extra = propBag.getPropertyAsInterface(
+                "extra",
+                Ci.nsIPropertyBag2
+              );
+
+              extraCheck(extra);
+            }
+
+            return true;
+          }
+        }
+        return false;
+      }
+    );
+    promises.push(promise);
+  }
+  return Promise.all(promises);
+}
+
+/**
+ * Returns a Promise that resolves once a .dmp.ignore file is created for
+ * the crashes in the pending directory matching the reportIDs being
+ * passed in.
+ *
+ * @param reportIDs (Array<string>)
+ *        The IDs for the reports that we expect CrashSubmit to have been
+ *        marked for ignoring.
+ * @returns Promise
+ */
+function waitForIgnoredReports(reportIDs) {
+  let dir = getPendingCrashReportDir();
+  let promises = [];
+  for (let reportID of reportIDs) {
+    let file = dir.clone();
+    file.append(reportID + ".dmp.ignore");
+    promises.push(IOUtils.exists(file.path));
+  }
+  return Promise.all(promises);
+}
+
+add_setup(async function () {
+  // Pending crash reports are stored in the UAppData folder,
+  // which exists outside of the profile folder. In order to
+  // not overwrite / clear pending crash reports for the poor
+  // soul who runs this test, we use AppData.sys.mjs to point to
+  // a special made-up directory inside the profile
+  // directory.
+  await makeFakeAppDir();
+  // We'll assume that the notifications will be shown in the current
+  // browser window's global notification box.
+
+  // If we happen to already be seeing the unsent crash report
+  // notification, it's because the developer running this test
+  // happened to have some unsent reports in their UAppDir.
+  // We'll remove the notification without touching those reports.
+  let notification = gNotificationBox.getNotificationWithValue(
+    "pending-crash-reports"
+  );
+  if (notification) {
+    notification.close();
+  }
+
+  let oldServerURL = Services.env.get("MOZ_CRASHREPORTER_URL");
+  Services.env.set("MOZ_CRASHREPORTER_URL", SERVER_URL);
+
+  // nsBrowserGlue starts up UnsubmittedCrashHandler automatically
+  // on a timer, so at this point, it can be in one of several states:
+  //
+  // 1. The timer hasn't yet finished, and an automatic scan for crash
+  //    reports is pending.
+  // 2. The timer has already gone off and the scan has already completed.
+  // 3. The handler is disabled.
+  //
+  // To collapse all of these possibilities, we uninit the UnsubmittedCrashHandler
+  // to cancel the timer, make sure it's preffed on, and then restart it (which
+  // doesn't restart the timer). Note that making the component initialize
+  // even when it's disabled is an intentional choice, as this allows for easier
+  // simulation of startup and shutdown.
+  UnsubmittedCrashHandler.uninit();
+
+  // While we're here, let's test that we don't show the notification
+  // if we're disabled and something happens to check for unsubmitted
+  // crash reports.
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.crashReports.unsubmittedCheck.enabled", false]],
+  });
+
+  await createPendingCrashReports(1);
+
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(!notification, "There should not be a notification");
+
+  clearPendingCrashReports();
+  await SpecialPowers.popPrefEnv();
+
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.crashReports.unsubmittedCheck.enabled", true]],
+  });
+  UnsubmittedCrashHandler.init();
+
+  registerCleanupFunction(function () {
+    clearPendingCrashReports();
+    Services.env.set("MOZ_CRASHREPORTER_URL", oldServerURL);
+  });
+});
+
+/**
+ * Tests that if there are no pending crash reports, then the
+ * notification will not show up.
+ */
+add_task(async function test_no_pending_no_notification() {
+  // Make absolutely sure there are no pending crash reports first...
+  clearPendingCrashReports();
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.equal(
+    notification,
+    null,
+    "There should not be a notification if there are no " +
+      "pending crash reports"
+  );
+});
+
+/**
+ * Tests that there is a notification if there is one pending
+ * crash report.
+ */
+add_task(async function test_one_pending() {
+  await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that an ignored crash report does not suppress a notification that
+ * would be trigged by another, unignored crash report.
+ */
+add_task(async function test_other_ignored() {
+  let toIgnore = await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  // Dismiss notification, creating the .dmp.ignore file
+  notification.closeButtonEl.click();
+  gNotificationBox.removeNotification(notification, true);
+  await waitForIgnoredReports(toIgnore);
+
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(!notification, "There should not be a notification");
+
+  await createPendingCrashReports(1);
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that there is a notification if there is more than one
+ * pending crash report.
+ */
+add_task(async function test_several_pending() {
+  await createPendingCrashReports(3);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that there is no notification if the only pending crash
+ * reports are over 28 days old. Also checks that if we put a newer
+ * crash with that older set, that we can still get a notification.
+ */
+add_task(async function test_several_pending() {
+  // Let's create some crash reports from 30 days ago.
+  let oldDate = new Date(Date.now() - 30 * DAY);
+  await createPendingCrashReports(3, oldDate);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.equal(
+    notification,
+    null,
+    "There should not be a notification if there are only " +
+      "old pending crash reports"
+  );
+  // Now let's create a new one and check again
+  await createPendingCrashReports(1);
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that the notification can submit a report.
+ */
+add_task(async function test_can_submit() {
+  function extraCheck(extra) {
+    const blockedAnnotations = [
+      "ServerURL",
+      "TelemetryClientId",
+      "TelemetryServerURL",
+      "TelemetrySessionId",
+    ];
+    for (const key of blockedAnnotations) {
+      Assert.ok(
+        !extra.hasKey(key),
+        "The " + key + " annotation should have been stripped away"
+      );
+    }
+
+    Assert.equal(extra.get("SubmittedFrom"), "Infobar");
+    Assert.equal(extra.get("Throttleable"), "1");
+  }
+
+  let reportIDs = await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  // Attempt to submit the notification by clicking on the submit
+  // button
+  let buttons = notification.buttonContainer.querySelectorAll(
+    ".notification-button"
+  );
+  // ...which should be the first button.
+  let submit = buttons[0];
+  let promiseReports = waitForSubmittedReports(reportIDs, extraCheck);
+  info("Sending crash report");
+  submit.click();
+  info("Sent!");
+  // We'll not wait for the notification to finish its transition -
+  // we'll just remove it right away.
+  gNotificationBox.removeNotification(notification, true);
+
+  info("Waiting on reports to be received.");
+  await promiseReports;
+  info("Received!");
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that the notification can submit multiple reports.
+ */
+add_task(async function test_can_submit_several() {
+  let reportIDs = await createPendingCrashReports(3);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  // Attempt to submit the notification by clicking on the submit
+  // button
+  let buttons = notification.buttonContainer.querySelectorAll(
+    ".notification-button"
+  );
+  // ...which should be the first button.
+  let submit = buttons[0];
+
+  let promiseReports = waitForSubmittedReports(reportIDs);
+  info("Sending crash reports");
+  submit.click();
+  info("Sent!");
+  // We'll not wait for the notification to finish its transition -
+  // we'll just remove it right away.
+  gNotificationBox.removeNotification(notification, true);
+
+  info("Waiting on reports to be received.");
+  await promiseReports;
+  info("Received!");
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that choosing "Send Always" flips the autoSubmit pref
+ * and sends the pending crash reports.
+ */
+add_task(async function test_can_submit_always() {
+  let pref = "browser.crashReports.unsubmittedCheck.autoSubmit2";
+  Assert.equal(
+    Services.prefs.getBoolPref(pref),
+    false,
+    "We should not be auto-submitting by default"
+  );
+
+  let reportIDs = await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  // Attempt to submit the notification by clicking on the send all
+  // button
+  let buttons = notification.buttonContainer.querySelectorAll(
+    ".notification-button"
+  );
+  // ...which should be the second button.
+  let sendAll = buttons[1];
+
+  let promiseReports = waitForSubmittedReports(reportIDs);
+  info("Sending crash reports");
+  sendAll.click();
+  info("Sent!");
+  // We'll not wait for the notification to finish its transition -
+  // we'll just remove it right away.
+  gNotificationBox.removeNotification(notification, true);
+
+  info("Waiting on reports to be received.");
+  await promiseReports;
+  info("Received!");
+
+  // Make sure the pref was set
+  Assert.equal(
+    Services.prefs.getBoolPref(pref),
+    true,
+    "The autoSubmit pref should have been set"
+  );
+
+  // Create another report
+  reportIDs = await createPendingCrashReports(1);
+  let result = await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+
+  // Check that the crash was auto-submitted
+  Assert.equal(result, null, "The notification should not be shown");
+  promiseReports = await waitForSubmittedReports(reportIDs, extra => {
+    Assert.equal(extra.get("SubmittedFrom"), "Auto");
+    Assert.equal(extra.get("Throttleable"), "1");
+  });
+
+  // And revert back to default now.
+  Services.prefs.clearUserPref(pref);
+
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if the user has chosen to automatically send
+ * crash reports that no notification is displayed to the
+ * user.
+ */
+add_task(async function test_can_auto_submit() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.crashReports.unsubmittedCheck.autoSubmit2", true]],
+  });
+
+  let reportIDs = await createPendingCrashReports(3);
+  let promiseReports = waitForSubmittedReports(reportIDs);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.equal(notification, null, "There should be no notification");
+  info("Waiting on reports to be received.");
+  await promiseReports;
+  info("Received!");
+
+  clearPendingCrashReports();
+  await SpecialPowers.popPrefEnv();
+});
+
+/**
+ * Tests that if the user chooses to dismiss the notification,
+ * then the current pending requests won't cause the notification
+ * to appear again in the future.
+ */
+add_task(async function test_can_ignore() {
+  let reportIDs = await createPendingCrashReports(3);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  // Dismiss the notification by clicking on the "X" button.
+  notification.closeButtonEl.click();
+  // We'll not wait for the notification to finish its transition -
+  // we'll just remove it right away.
+  gNotificationBox.removeNotification(notification, true);
+  await waitForIgnoredReports(reportIDs);
+
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.equal(notification, null, "There should be no notification");
+
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if the notification is shown, then the
+ * lastShownDate is set for today.
+ */
+add_task(async function test_last_shown_date() {
+  await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  let today = UnsubmittedCrashHandler.dateString(new Date());
+  let lastShownDate =
+    UnsubmittedCrashHandler.prefs.getCharPref("lastShownDate");
+  Assert.equal(today, lastShownDate, "Last shown date should be today.");
+
+  UnsubmittedCrashHandler.prefs.clearUserPref("lastShownDate");
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if UnsubmittedCrashHandler is uninit with a
+ * notification still being shown, that
+ * browser.crashReports.unsubmittedCheck.shutdownWhileShowing is
+ * set to true.
+ */
+add_task(async function test_shutdown_while_showing() {
+  await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  UnsubmittedCrashHandler.uninit();
+  let shutdownWhileShowing = UnsubmittedCrashHandler.prefs.getBoolPref(
+    "shutdownWhileShowing"
+  );
+  Assert.ok(
+    shutdownWhileShowing,
+    "We should have noticed that we uninitted while showing " +
+      "the notification."
+  );
+  UnsubmittedCrashHandler.prefs.clearUserPref("shutdownWhileShowing");
+  UnsubmittedCrashHandler.init();
+
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if UnsubmittedCrashHandler is uninit after
+ * the notification has been closed, that
+ * browser.crashReports.unsubmittedCheck.shutdownWhileShowing is
+ * not set in prefs.
+ */
+add_task(async function test_shutdown_while_not_showing() {
+  let reportIDs = await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  // Dismiss the notification by clicking on the "X" button.
+  notification.closeButtonEl.click();
+  // We'll not wait for the notification to finish its transition -
+  // we'll just remove it right away.
+  gNotificationBox.removeNotification(notification, true);
+
+  await waitForIgnoredReports(reportIDs);
+
+  UnsubmittedCrashHandler.uninit();
+  Assert.throws(
+    () => {
+      UnsubmittedCrashHandler.prefs.getBoolPref("shutdownWhileShowing");
+    },
+    /NS_ERROR_UNEXPECTED/,
+    "We should have noticed that the notification had closed before uninitting."
+  );
+  UnsubmittedCrashHandler.init();
+
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if
+ * browser.crashReports.unsubmittedCheck.shutdownWhileShowing is
+ * set and the lastShownDate is today, then we don't decrement
+ * browser.crashReports.unsubmittedCheck.chancesUntilSuppress.
+ */
+add_task(async function test_dont_decrement_chances_on_same_day() {
+  let initChances = UnsubmittedCrashHandler.prefs.getIntPref(
+    "chancesUntilSuppress"
+  );
+  Assert.greater(initChances, 1, "We should start with at least 1 chance.");
+
+  await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  UnsubmittedCrashHandler.uninit();
+
+  gNotificationBox.removeNotification(notification, true);
+
+  let shutdownWhileShowing = UnsubmittedCrashHandler.prefs.getBoolPref(
+    "shutdownWhileShowing"
+  );
+  Assert.ok(
+    shutdownWhileShowing,
+    "We should have noticed that we uninitted while showing " +
+      "the notification."
+  );
+
+  let today = UnsubmittedCrashHandler.dateString(new Date());
+  let lastShownDate =
+    UnsubmittedCrashHandler.prefs.getCharPref("lastShownDate");
+  Assert.equal(today, lastShownDate, "Last shown date should be today.");
+
+  UnsubmittedCrashHandler.init();
+
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should still be a notification");
+
+  let chances = UnsubmittedCrashHandler.prefs.getIntPref(
+    "chancesUntilSuppress"
+  );
+
+  Assert.equal(initChances, chances, "We should not have decremented chances.");
+
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if
+ * browser.crashReports.unsubmittedCheck.shutdownWhileShowing is
+ * set and the lastShownDate is before today, then we decrement
+ * browser.crashReports.unsubmittedCheck.chancesUntilSuppress.
+ */
+add_task(async function test_decrement_chances_on_other_day() {
+  let initChances = UnsubmittedCrashHandler.prefs.getIntPref(
+    "chancesUntilSuppress"
+  );
+  Assert.greater(initChances, 1, "We should start with at least 1 chance.");
+
+  await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should be a notification");
+
+  UnsubmittedCrashHandler.uninit();
+
+  gNotificationBox.removeNotification(notification, true);
+
+  let shutdownWhileShowing = UnsubmittedCrashHandler.prefs.getBoolPref(
+    "shutdownWhileShowing"
+  );
+  Assert.ok(
+    shutdownWhileShowing,
+    "We should have noticed that we uninitted while showing " +
+      "the notification."
+  );
+
+  // Now pretend that the notification was shown yesterday.
+  let yesterday = UnsubmittedCrashHandler.dateString(
+    new Date(Date.now() - DAY)
+  );
+  UnsubmittedCrashHandler.prefs.setCharPref("lastShownDate", yesterday);
+
+  UnsubmittedCrashHandler.init();
+
+  notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.ok(notification, "There should still be a notification");
+
+  let chances = UnsubmittedCrashHandler.prefs.getIntPref(
+    "chancesUntilSuppress"
+  );
+
+  Assert.equal(
+    initChances - 1,
+    chances,
+    "We should have decremented our chances."
+  );
+  UnsubmittedCrashHandler.prefs.clearUserPref("chancesUntilSuppress");
+
+  gNotificationBox.removeNotification(notification, true);
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if we've shutdown too many times showing the
+ * notification, and we've run out of chances, then
+ * browser.crashReports.unsubmittedCheck.suppressUntilDate is
+ * set for some days into the future.
+ */
+add_task(async function test_can_suppress_after_chances() {
+  // Pretend that a notification was shown yesterday.
+  let yesterday = UnsubmittedCrashHandler.dateString(
+    new Date(Date.now() - DAY)
+  );
+  UnsubmittedCrashHandler.prefs.setCharPref("lastShownDate", yesterday);
+  UnsubmittedCrashHandler.prefs.setBoolPref("shutdownWhileShowing", true);
+  UnsubmittedCrashHandler.prefs.setIntPref("chancesUntilSuppress", 0);
+
+  await createPendingCrashReports(1);
+  let notification =
+    await UnsubmittedCrashHandler.checkForUnsubmittedCrashReports();
+  Assert.equal(
+    notification,
+    null,
+    "There should be no notification if we've run out of chances"
+  );
+
+  // We should have set suppressUntilDate into the future
+  let suppressUntilDate =
+    UnsubmittedCrashHandler.prefs.getCharPref("suppressUntilDate");
+
+  let today = UnsubmittedCrashHandler.dateString(new Date());
+  Assert.ok(
+    suppressUntilDate > today,
+    "We should be suppressing until some days into the future."
+  );
+
+  UnsubmittedCrashHandler.prefs.clearUserPref("chancesUntilSuppress");
+  UnsubmittedCrashHandler.prefs.clearUserPref("suppressUntilDate");
+  UnsubmittedCrashHandler.prefs.clearUserPref("lastShownDate");
+  clearPendingCrashReports();
+});
+
+/**
+ * Tests that if there's a suppression date set, then no notification
+ * will be shown even if there are pending crash reports.
+ */
+add_task(async function test_suppression() {
+  let future = UnsubmittedCrashHandler.dateString(
+    new Date(Date.now() + DAY * 5)
+  );
+  UnsubmittedCrashHandler.prefs.setCharPref("suppressUntilDate", future);
+  UnsubmittedCrashHandler.uninit();
+  UnsubmittedCrashHandler.init();
+
+  Assert.ok(
+    UnsubmittedCrashHandler.suppressed,
+    "The UnsubmittedCrashHandler should be suppressed."
+  );
+  UnsubmittedCrashHandler.prefs.clearUserPref("suppressUntilDate");
+
+  UnsubmittedCrashHandler.uninit();
+  UnsubmittedCrashHandler.init();
+});
+
+/**
+ * Tests that if there's a suppression date set, but we've exceeded
+ * it, then we can show the notification again.
+ */
+add_task(async function test_end_suppression() {
+  let yesterday = UnsubmittedCrashHandler.dateString(
+    new Date(Date.now() - DAY)
+  );
+  UnsubmittedCrashHandler.prefs.setCharPref("suppressUntilDate", yesterday);
+  UnsubmittedCrashHandler.uninit();
+  UnsubmittedCrashHandler.init();
+
+  Assert.ok(
+    !UnsubmittedCrashHandler.suppressed,
+    "The UnsubmittedCrashHandler should not be suppressed."
+  );
+  Assert.ok(
+    !UnsubmittedCrashHandler.prefs.prefHasUserValue("suppressUntilDate"),
+    "The suppression date should been cleared from preferences."
+  );
+
+  UnsubmittedCrashHandler.uninit();
+  UnsubmittedCrashHandler.init();
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry.js b/browser/modules/test/browser/browser_UsageTelemetry.js
new file mode 100644
index 0000000000..9934723f37
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry.js
@@ -0,0 +1,696 @@
+"use strict";
+
+requestLongerTimeout(2);
+
+const MAX_CONCURRENT_TABS = "browser.engagement.max_concurrent_tab_count";
+const TAB_EVENT_COUNT = "browser.engagement.tab_open_event_count";
+const MAX_CONCURRENT_WINDOWS = "browser.engagement.max_concurrent_window_count";
+const MAX_TAB_PINNED = "browser.engagement.max_concurrent_tab_pinned_count";
+const TAB_PINNED_EVENT = "browser.engagement.tab_pinned_event_count";
+const WINDOW_OPEN_COUNT = "browser.engagement.window_open_event_count";
+const TOTAL_URI_COUNT = "browser.engagement.total_uri_count";
+const UNIQUE_DOMAINS_COUNT = "browser.engagement.unique_domains_count";
+const UNFILTERED_URI_COUNT = "browser.engagement.unfiltered_uri_count";
+const TOTAL_URI_COUNT_NORMAL_AND_PRIVATE_MODE =
+  "browser.engagement.total_uri_count_normal_and_private_mode";
+
+const TELEMETRY_SUBSESSION_TOPIC = "internal-telemetry-after-subsession-split";
+
+const RESTORE_ON_DEMAND_PREF = "browser.sessionstore.restore_on-demand";
+
+ChromeUtils.defineESModuleGetters(this, {
+  MINIMUM_TAB_COUNT_INTERVAL_MS:
+    "resource:///modules/BrowserUsageTelemetry.sys.mjs",
+});
+
+const { ObjectUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/ObjectUtils.sys.mjs"
+);
+
+BrowserUsageTelemetry._onTabsOpenedTask._timeoutMs = 0;
+registerCleanupFunction(() => {
+  BrowserUsageTelemetry._onTabsOpenedTask._timeoutMs = undefined;
+});
+
+// Reset internal URI counter in case URIs were opened by other tests.
+Services.obs.notifyObservers(null, TELEMETRY_SUBSESSION_TOPIC);
+
+/**
+ * Get a snapshot of the scalars and check them against the provided values.
+ */
+let checkScalars = (countsObject, skipGleanCheck = false) => {
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  // Check the expected values. Scalars that are never set must not be reported.
+  const checkScalar = (key, val, msg) =>
+    val > 0
+      ? TelemetryTestUtils.assertScalar(scalars, key, val, msg)
+      : TelemetryTestUtils.assertScalarUnset(scalars, key);
+  checkScalar(
+    MAX_CONCURRENT_TABS,
+    countsObject.maxTabs,
+    "The maximum tab count must match the expected value."
+  );
+  checkScalar(
+    TAB_EVENT_COUNT,
+    countsObject.tabOpenCount,
+    "The number of open tab event count must match the expected value."
+  );
+  checkScalar(
+    MAX_TAB_PINNED,
+    countsObject.maxTabsPinned,
+    "The maximum tabs pinned count must match the expected value."
+  );
+  checkScalar(
+    TAB_PINNED_EVENT,
+    countsObject.tabPinnedCount,
+    "The number of tab pinned event count must match the expected value."
+  );
+  checkScalar(
+    MAX_CONCURRENT_WINDOWS,
+    countsObject.maxWindows,
+    "The maximum window count must match the expected value."
+  );
+  checkScalar(
+    WINDOW_OPEN_COUNT,
+    countsObject.windowsOpenCount,
+    "The number of window open event count must match the expected value."
+  );
+  checkScalar(
+    TOTAL_URI_COUNT,
+    countsObject.totalURIs,
+    "The total URI count must match the expected value."
+  );
+  checkScalar(
+    UNIQUE_DOMAINS_COUNT,
+    countsObject.domainCount,
+    "The unique domains count must match the expected value."
+  );
+  checkScalar(
+    UNFILTERED_URI_COUNT,
+    countsObject.totalUnfilteredURIs,
+    "The unfiltered URI count must match the expected value."
+  );
+  checkScalar(
+    TOTAL_URI_COUNT_NORMAL_AND_PRIVATE_MODE,
+    countsObject.totalURIsNormalAndPrivateMode,
+    "The total URI count for both normal and private mode must match the expected value."
+  );
+  if (!skipGleanCheck) {
+    if (countsObject.totalURIsNormalAndPrivateMode == 0) {
+      Assert.equal(
+        Glean.browserEngagement.uriCount.testGetValue(),
+        undefined,
+        "Total URI count reported in Glean must be unset."
+      );
+    } else {
+      Assert.equal(
+        countsObject.totalURIsNormalAndPrivateMode,
+        Glean.browserEngagement.uriCount.testGetValue(),
+        "The total URI count reported in Glean must be as expected."
+      );
+    }
+  }
+};
+
+add_task(async function test_tabsAndWindows() {
+  // Let's reset the counts.
+  Services.telemetry.clearScalars();
+  Services.fog.testResetFOG();
+
+  let openedTabs = [];
+  let expectedTabOpenCount = 0;
+  let expectedWinOpenCount = 0;
+  let expectedMaxTabs = 0;
+  let expectedMaxWins = 0;
+  let expectedMaxTabsPinned = 0;
+  let expectedTabPinned = 0;
+  let expectedTotalURIs = 0;
+
+  // Add a new tab and check that the count is right.
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+  );
+
+  gBrowser.pinTab(openedTabs[0]);
+  gBrowser.unpinTab(openedTabs[0]);
+
+  expectedTabOpenCount = 1;
+  expectedMaxTabs = 2;
+  expectedMaxTabsPinned = 1;
+  expectedTabPinned += 1;
+  // This, and all the checks below, also check that initial pages (about:newtab, about:blank, ..)
+  // are not counted by the total_uri_count and the unfiltered_uri_count probes.
+  checkScalars({
+    maxTabs: expectedMaxTabs,
+    tabOpenCount: expectedTabOpenCount,
+    maxWindows: expectedMaxWins,
+    windowsOpenCount: expectedWinOpenCount,
+    totalURIs: expectedTotalURIs,
+    domainCount: 0,
+    totalUnfilteredURIs: 0,
+    maxTabsPinned: expectedMaxTabsPinned,
+    tabPinnedCount: expectedTabPinned,
+    totalURIsNormalAndPrivateMode: expectedTotalURIs,
+  });
+
+  // Add two new tabs in the same window.
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+  );
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+  );
+
+  gBrowser.pinTab(openedTabs[1]);
+  gBrowser.pinTab(openedTabs[2]);
+  gBrowser.unpinTab(openedTabs[2]);
+  gBrowser.unpinTab(openedTabs[1]);
+
+  expectedTabOpenCount += 2;
+  expectedMaxTabs += 2;
+  expectedMaxTabsPinned = 2;
+  expectedTabPinned += 2;
+  checkScalars({
+    maxTabs: expectedMaxTabs,
+    tabOpenCount: expectedTabOpenCount,
+    maxWindows: expectedMaxWins,
+    windowsOpenCount: expectedWinOpenCount,
+    totalURIs: expectedTotalURIs,
+    domainCount: 0,
+    totalUnfilteredURIs: 0,
+    maxTabsPinned: expectedMaxTabsPinned,
+    tabPinnedCount: expectedTabPinned,
+    totalURIsNormalAndPrivateMode: expectedTotalURIs,
+  });
+
+  // Add a new window and then some tabs in it. An empty new windows counts as a tab.
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.firstBrowserLoaded(win);
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:blank")
+  );
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:blank")
+  );
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+  );
+  // The new window started with a new tab, so account for it.
+  expectedTabOpenCount += 4;
+  expectedWinOpenCount += 1;
+  expectedMaxWins = 2;
+  expectedMaxTabs += 4;
+
+  // Remove a tab from the first window, the max shouldn't change.
+  BrowserTestUtils.removeTab(openedTabs.pop());
+  checkScalars({
+    maxTabs: expectedMaxTabs,
+    tabOpenCount: expectedTabOpenCount,
+    maxWindows: expectedMaxWins,
+    windowsOpenCount: expectedWinOpenCount,
+    totalURIs: expectedTotalURIs,
+    domainCount: 0,
+    totalUnfilteredURIs: 0,
+    maxTabsPinned: expectedMaxTabsPinned,
+    tabPinnedCount: expectedTabPinned,
+    totalURIsNormalAndPrivateMode: expectedTotalURIs,
+  });
+
+  // Remove all the extra windows and tabs.
+  for (let tab of openedTabs) {
+    BrowserTestUtils.removeTab(tab);
+  }
+  await BrowserTestUtils.closeWindow(win);
+
+  // Make sure all the scalars still have the expected values.
+  checkScalars({
+    maxTabs: expectedMaxTabs,
+    tabOpenCount: expectedTabOpenCount,
+    maxWindows: expectedMaxWins,
+    windowsOpenCount: expectedWinOpenCount,
+    totalURIs: expectedTotalURIs,
+    domainCount: 0,
+    totalUnfilteredURIs: 0,
+    maxTabsPinned: expectedMaxTabsPinned,
+    tabPinnedCount: expectedTabPinned,
+    totalURIsNormalAndPrivateMode: expectedTotalURIs,
+  });
+});
+
+add_task(async function test_subsessionSplit() {
+  // Let's reset the counts.
+  Services.telemetry.clearScalars();
+
+  // Add a new window (that will have 4 tabs).
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.firstBrowserLoaded(win);
+  let openedTabs = [];
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:blank")
+  );
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:mozilla")
+  );
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(
+      win.gBrowser,
+      "http://www.example.com"
+    )
+  );
+
+  // Check that the scalars have the right values. We expect 2 unfiltered URI loads
+  // (about:mozilla and www.example.com, but no about:blank) and 1 URI totalURIs
+  // (only www.example.com).
+  let expectedTotalURIs = 1;
+
+  checkScalars({
+    maxTabs: 5,
+    tabOpenCount: 4,
+    maxWindows: 2,
+    windowsOpenCount: 1,
+    totalURIs: expectedTotalURIs,
+    domainCount: 1,
+    totalUnfilteredURIs: 2,
+    maxTabsPinned: 0,
+    tabPinnedCount: 0,
+    totalURIsNormalAndPrivateMode: expectedTotalURIs,
+  });
+
+  // Remove a tab.
+  BrowserTestUtils.removeTab(openedTabs.pop());
+
+  // Simulate a subsession split by clearing the scalars (via |getSnapshotForScalars|) and
+  // notifying the subsession split topic.
+  Services.telemetry.getSnapshotForScalars("main", true /* clearScalars */);
+  Services.obs.notifyObservers(null, TELEMETRY_SUBSESSION_TOPIC);
+
+  // After a subsession split, only the MAX_CONCURRENT_* scalars must be available
+  // and have the correct value. No tabs, windows or URIs were opened so other scalars
+  // must not be reported.
+  expectedTotalURIs = 0;
+
+  checkScalars(
+    {
+      maxTabs: 4,
+      tabOpenCount: 0,
+      maxWindows: 2,
+      windowsOpenCount: 0,
+      totalURIs: expectedTotalURIs,
+      domainCount: 0,
+      totalUnfilteredURIs: 0,
+      maxTabsPinned: 0,
+      tabPinnedCount: 0,
+      totalURIsNormalAndPrivateMode: expectedTotalURIs,
+    },
+    true
+  );
+
+  // Remove all the extra windows and tabs.
+  for (let tab of openedTabs) {
+    BrowserTestUtils.removeTab(tab);
+  }
+  await BrowserTestUtils.closeWindow(win);
+});
+
+function checkTabCountHistogram(result, expected, message) {
+  Assert.deepEqual(result.values, expected, message);
+}
+
+add_task(async function test_tabsHistogram() {
+  let openedTabs = [];
+  let tabCountHist = TelemetryTestUtils.getAndClearHistogram("TAB_COUNT");
+
+  checkTabCountHistogram(
+    tabCountHist.snapshot(),
+    {},
+    "TAB_COUNT telemetry - initial tab counts"
+  );
+
+  // Add a new tab and check that the count is right.
+  BrowserUsageTelemetry._lastRecordTabCount = 0;
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+  );
+  checkTabCountHistogram(
+    tabCountHist.snapshot(),
+    { 1: 0, 2: 1, 3: 0 },
+    "TAB_COUNT telemetry - opening tabs"
+  );
+
+  // Open a different page and check the counts.
+  BrowserUsageTelemetry._lastRecordTabCount = 0;
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  openedTabs.push(tab);
+  BrowserUsageTelemetry._lastRecordTabCount = 0;
+  BrowserTestUtils.startLoadingURIString(
+    tab.linkedBrowser,
+    "http://example.com/"
+  );
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false,
+    "http://example.com/"
+  );
+  checkTabCountHistogram(
+    tabCountHist.snapshot(),
+    { 1: 0, 2: 1, 3: 2, 4: 0 },
+    "TAB_COUNT telemetry - loading page"
+  );
+
+  // Open another tab
+  BrowserUsageTelemetry._lastRecordTabCount = 0;
+  openedTabs.push(
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+  );
+  checkTabCountHistogram(
+    tabCountHist.snapshot(),
+    { 1: 0, 2: 1, 3: 2, 4: 1, 5: 0 },
+    "TAB_COUNT telemetry - opening more tabs"
+  );
+
+  // Add a new window and then some tabs in it. A new window starts with one tab.
+  BrowserUsageTelemetry._lastRecordTabCount = 0;
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.firstBrowserLoaded(win);
+  checkTabCountHistogram(
+    tabCountHist.snapshot(),
+    { 1: 0, 2: 1, 3: 2, 4: 1, 5: 1, 6: 0 },
+    "TAB_COUNT telemetry - opening window"
+  );
+
+  // Do not trigger a recount if _lastRecordTabCount is recent on new tab
+  BrowserUsageTelemetry._lastRecordTabCount =
+    Date.now() - MINIMUM_TAB_COUNT_INTERVAL_MS / 2;
+  {
+    let oldLastRecordTabCount = BrowserUsageTelemetry._lastRecordTabCount;
+    openedTabs.push(
+      await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:blank")
+    );
+    checkTabCountHistogram(
+      tabCountHist.snapshot(),
+      { 1: 0, 2: 1, 3: 2, 4: 1, 5: 1, 6: 0 },
+      "TAB_COUNT telemetry - new tab, recount event ignored"
+    );
+    Assert.equal(
+      BrowserUsageTelemetry._lastRecordTabCount,
+      oldLastRecordTabCount,
+      "TAB_COUNT telemetry - _lastRecordTabCount unchanged"
+    );
+  }
+
+  // Trigger a recount if _lastRecordTabCount has passed on new tab
+  BrowserUsageTelemetry._lastRecordTabCount =
+    Date.now() - (MINIMUM_TAB_COUNT_INTERVAL_MS + 1000);
+  {
+    let oldLastRecordTabCount = BrowserUsageTelemetry._lastRecordTabCount;
+    openedTabs.push(
+      await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:blank")
+    );
+    checkTabCountHistogram(
+      tabCountHist.snapshot(),
+      { 1: 0, 2: 1, 3: 2, 4: 1, 5: 1, 7: 1, 8: 0 },
+      "TAB_COUNT telemetry - new tab, recount event included"
+    );
+    Assert.notEqual(
+      BrowserUsageTelemetry._lastRecordTabCount,
+      oldLastRecordTabCount,
+      "TAB_COUNT telemetry - _lastRecordTabCount updated"
+    );
+    Assert.greater(
+      BrowserUsageTelemetry._lastRecordTabCount,
+      Date.now() - MINIMUM_TAB_COUNT_INTERVAL_MS,
+      "TAB_COUNT telemetry - _lastRecordTabCount invariant"
+    );
+  }
+
+  // Do not trigger a recount if _lastRecordTabCount is recent on page load
+  BrowserUsageTelemetry._lastRecordTabCount =
+    Date.now() - MINIMUM_TAB_COUNT_INTERVAL_MS / 2;
+  {
+    let oldLastRecordTabCount = BrowserUsageTelemetry._lastRecordTabCount;
+    BrowserTestUtils.startLoadingURIString(
+      tab.linkedBrowser,
+      "http://example.com/"
+    );
+    await BrowserTestUtils.browserLoaded(
+      tab.linkedBrowser,
+      false,
+      "http://example.com/"
+    );
+    checkTabCountHistogram(
+      tabCountHist.snapshot(),
+      { 1: 0, 2: 1, 3: 2, 4: 1, 5: 1, 7: 1, 8: 0 },
+      "TAB_COUNT telemetry - page load, recount event ignored"
+    );
+    Assert.equal(
+      BrowserUsageTelemetry._lastRecordTabCount,
+      oldLastRecordTabCount,
+      "TAB_COUNT telemetry - _lastRecordTabCount unchanged"
+    );
+  }
+
+  // Trigger a recount if _lastRecordTabCount has passed on page load
+  BrowserUsageTelemetry._lastRecordTabCount =
+    Date.now() - (MINIMUM_TAB_COUNT_INTERVAL_MS + 1000);
+  {
+    let oldLastRecordTabCount = BrowserUsageTelemetry._lastRecordTabCount;
+    BrowserTestUtils.startLoadingURIString(
+      tab.linkedBrowser,
+      "http://example.com/"
+    );
+    await BrowserTestUtils.browserLoaded(
+      tab.linkedBrowser,
+      false,
+      "http://example.com/"
+    );
+    checkTabCountHistogram(
+      tabCountHist.snapshot(),
+      { 1: 0, 2: 1, 3: 2, 4: 1, 5: 1, 7: 2, 8: 0 },
+      "TAB_COUNT telemetry - page load, recount event included"
+    );
+    Assert.notEqual(
+      BrowserUsageTelemetry._lastRecordTabCount,
+      oldLastRecordTabCount,
+      "TAB_COUNT telemetry - _lastRecordTabCount updated"
+    );
+    Assert.greater(
+      BrowserUsageTelemetry._lastRecordTabCount,
+      Date.now() - MINIMUM_TAB_COUNT_INTERVAL_MS,
+      "TAB_COUNT telemetry - _lastRecordTabCount invariant"
+    );
+  }
+
+  // Remove all the extra windows and tabs.
+  for (let openTab of openedTabs) {
+    BrowserTestUtils.removeTab(openTab);
+  }
+  await BrowserTestUtils.closeWindow(win);
+});
+
+add_task(async function test_loadedTabsHistogram() {
+  Services.prefs.setBoolPref(RESTORE_ON_DEMAND_PREF, true);
+  registerCleanupFunction(() =>
+    Services.prefs.clearUserPref(RESTORE_ON_DEMAND_PREF)
+  );
+
+  function resetTimestamps() {
+    BrowserUsageTelemetry._lastRecordTabCount = 0;
+    BrowserUsageTelemetry._lastRecordLoadedTabCount = 0;
+  }
+
+  resetTimestamps();
+  const tabCount = TelemetryTestUtils.getAndClearHistogram("TAB_COUNT");
+  const loadedTabCount =
+    TelemetryTestUtils.getAndClearHistogram("LOADED_TAB_COUNT");
+
+  checkTabCountHistogram(tabCount.snapshot(), {}, "TAB_COUNT - initial count");
+  checkTabCountHistogram(
+    loadedTabCount.snapshot(),
+    {},
+    "LOADED_TAB_COUNT - initial count"
+  );
+
+  resetTimestamps();
+  const tabs = [
+    await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank"),
+  ];
+
+  // There are two tabs open: the mochi.test tab and the foreground tab.
+  const snapshot = loadedTabCount.snapshot();
+  checkTabCountHistogram(snapshot, { 1: 0, 2: 1, 3: 0 }, "TAB_COUNT - new tab");
+
+  // Open a pending tab, as if by session restore.
+  resetTimestamps();
+  const lazyTab = BrowserTestUtils.addTab(gBrowser, "about:mozilla", {
+    createLazyBrowser: true,
+  });
+  tabs.push(lazyTab);
+
+  await BrowserTestUtils.waitForCondition(
+    () => !ObjectUtils.deepEqual(snapshot, tabCount.snapshot())
+  );
+
+  checkTabCountHistogram(
+    tabCount.snapshot(),
+    { 1: 0, 2: 1, 3: 1, 4: 0 },
+    "TAB_COUNT - Added pending tab"
+  );
+
+  // Only the mochi.test and foreground tab are loaded.
+  checkTabCountHistogram(
+    loadedTabCount.snapshot(),
+    { 1: 0, 2: 2, 3: 0 },
+    "LOADED_TAB_COUNT - Added pending tab"
+  );
+
+  resetTimestamps();
+  const restoredEvent = BrowserTestUtils.waitForEvent(lazyTab, "SSTabRestored");
+  await BrowserTestUtils.switchTab(gBrowser, lazyTab);
+  await restoredEvent;
+
+  checkTabCountHistogram(
+    tabCount.snapshot(),
+    { 1: 0, 2: 1, 3: 1, 4: 0 },
+    "TAB_COUNT - Restored pending tab"
+  );
+
+  checkTabCountHistogram(
+    loadedTabCount.snapshot(),
+    { 1: 0, 2: 2, 3: 1, 4: 0 },
+    "LOADED_TAB_COUNT - Restored pending tab"
+  );
+
+  resetTimestamps();
+
+  await Promise.all([
+    BrowserTestUtils.startLoadingURIString(
+      lazyTab.linkedBrowser,
+      "http://example.com/"
+    ),
+    BrowserTestUtils.browserLoaded(
+      lazyTab.linkedBrowser,
+      false,
+      "http://example.com/"
+    ),
+  ]);
+
+  checkTabCountHistogram(
+    tabCount.snapshot(),
+    { 1: 0, 2: 1, 3: 2, 4: 0 },
+    "TAB_COUNT - Navigated in existing tab"
+  );
+
+  checkTabCountHistogram(
+    loadedTabCount.snapshot(),
+    { 1: 0, 2: 2, 3: 2, 4: 0 },
+    "LOADED_TAB_COUNT - Navigated in existing tab"
+  );
+
+  resetTimestamps();
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.firstBrowserLoaded(win);
+
+  // The new window will have a new tab.
+  checkTabCountHistogram(
+    tabCount.snapshot(),
+    { 1: 0, 2: 1, 3: 2, 4: 1, 5: 0 },
+    "TAB_COUNT - Opened new window"
+  );
+
+  checkTabCountHistogram(
+    loadedTabCount.snapshot(),
+    { 1: 0, 2: 2, 3: 2, 4: 1, 5: 0 },
+    "LOADED_TAB_COUNT - Opened new window"
+  );
+
+  resetTimestamps();
+  await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "about:robots");
+  checkTabCountHistogram(
+    tabCount.snapshot(),
+    { 1: 0, 2: 1, 3: 2, 4: 1, 5: 1, 6: 0 },
+    "TAB_COUNT - Opened new tab in new window"
+  );
+
+  checkTabCountHistogram(
+    loadedTabCount.snapshot(),
+    { 1: 0, 2: 2, 3: 2, 4: 1, 5: 1, 6: 0 },
+    "LOADED_TAB_COUNT - Opened new tab in new window"
+  );
+
+  for (const tab of tabs) {
+    BrowserTestUtils.removeTab(tab);
+  }
+
+  await BrowserTestUtils.closeWindow(win);
+});
+
+add_task(async function test_restored_max_pinned_count() {
+  // Following pinned tab testing example from
+  // https://searchfox.org/mozilla-central/rev/1843375acbbca68127713e402be222350ac99301/browser/components/sessionstore/test/browser_pinned_tabs.js
+  Services.telemetry.clearScalars();
+  const { E10SUtils } = ChromeUtils.importESModule(
+    "resource://gre/modules/E10SUtils.sys.mjs"
+  );
+  const BACKUP_STATE = SessionStore.getBrowserState();
+  const triggeringPrincipal_base64 = E10SUtils.SERIALIZED_SYSTEMPRINCIPAL;
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.sessionstore.restore_on_demand", true],
+      ["browser.sessionstore.restore_tabs_lazily", true],
+    ],
+  });
+  let sessionRestoredPromise = new Promise(resolve => {
+    Services.obs.addObserver(resolve, "sessionstore-browser-state-restored");
+  });
+
+  info("Set browser state to 1 pinned tab.");
+  await SessionStore.setBrowserState(
+    JSON.stringify({
+      windows: [
+        {
+          selected: 1,
+          tabs: [
+            {
+              pinned: true,
+              entries: [
+                { url: "https://example.com", triggeringPrincipal_base64 },
+              ],
+            },
+          ],
+        },
+      ],
+    })
+  );
+
+  info("Await `sessionstore-browser-state-restored` promise.");
+  await sessionRestoredPromise;
+
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  TelemetryTestUtils.assertScalar(
+    scalars,
+    MAX_TAB_PINNED,
+    1,
+    "The maximum tabs pinned count must match the expected value."
+  );
+
+  gBrowser.unpinTab(gBrowser.selectedTab);
+
+  TelemetryTestUtils.assertScalar(
+    scalars,
+    MAX_TAB_PINNED,
+    1,
+    "The maximum tabs pinned count must match the expected value."
+  );
+
+  sessionRestoredPromise = new Promise(resolve => {
+    Services.obs.addObserver(resolve, "sessionstore-browser-state-restored");
+  });
+  await SessionStore.setBrowserState(BACKUP_STATE);
+  await SpecialPowers.popPrefEnv();
+  await sessionRestoredPromise;
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry_content_aboutRestartRequired.js b/browser/modules/test/browser/browser_UsageTelemetry_content_aboutRestartRequired.js
new file mode 100644
index 0000000000..3baa336d79
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry_content_aboutRestartRequired.js
@@ -0,0 +1,33 @@
+"use strict";
+
+const SCALAR_BUILDID_MISMATCH = "dom.contentprocess.buildID_mismatch";
+
+add_task(async function test_aboutRestartRequired() {
+  const { TabCrashHandler } = ChromeUtils.importESModule(
+    "resource:///modules/ContentCrashHandlers.sys.mjs"
+  );
+
+  // Let's reset the counts.
+  Services.telemetry.clearScalars();
+
+  let scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  // Check preconditions
+  is(
+    scalars[SCALAR_BUILDID_MISMATCH],
+    undefined,
+    "Build ID mismatch count should be undefined"
+  );
+
+  // Simulate buildID mismatch
+  TabCrashHandler._crashedTabCount = 1;
+  TabCrashHandler.sendToRestartRequiredPage(gBrowser.selectedTab.linkedBrowser);
+
+  scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  is(
+    scalars[SCALAR_BUILDID_MISMATCH],
+    1,
+    "Build ID mismatch count should be 1."
+  );
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry_domains.js b/browser/modules/test/browser/browser_UsageTelemetry_domains.js
new file mode 100644
index 0000000000..453272ea6b
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry_domains.js
@@ -0,0 +1,196 @@
+"use strict";
+
+const TOTAL_URI_COUNT = "browser.engagement.total_uri_count";
+const UNIQUE_DOMAINS_COUNT = "browser.engagement.unique_domains_count";
+const UNFILTERED_URI_COUNT = "browser.engagement.unfiltered_uri_count";
+const TELEMETRY_SUBSESSION_TOPIC = "internal-telemetry-after-subsession-split";
+
+// Reset internal URI counter in case URIs were opened by other tests.
+Services.obs.notifyObservers(null, TELEMETRY_SUBSESSION_TOPIC);
+
+/**
+ * Waits for the web progress listener associated with this tab to fire an
+ * onLocationChange for a non-error page.
+ *
+ * @param {xul:browser} browser
+ *        A xul:browser.
+ *
+ * @return {Promise}
+ * @resolves When navigating to a non-error page.
+ */
+function browserLocationChanged(browser) {
+  return new Promise(resolve => {
+    let wpl = {
+      onStateChange() {},
+      onSecurityChange() {},
+      onStatusChange() {},
+      onContentBlockingEvent() {},
+      onLocationChange(aWebProgress, aRequest, aURI, aFlags) {
+        if (!(aFlags & Ci.nsIWebProgressListener.LOCATION_CHANGE_ERROR_PAGE)) {
+          browser.webProgress.removeProgressListener(filter);
+          filter.removeProgressListener(wpl);
+          resolve();
+        }
+      },
+      QueryInterface: ChromeUtils.generateQI([
+        "nsIWebProgressListener",
+        "nsIWebProgressListener2",
+      ]),
+    };
+    const filter = Cc[
+      "@mozilla.org/appshell/component/browser-status-filter;1"
+    ].createInstance(Ci.nsIWebProgress);
+    filter.addProgressListener(wpl, Ci.nsIWebProgress.NOTIFY_ALL);
+    browser.webProgress.addProgressListener(
+      filter,
+      Ci.nsIWebProgress.NOTIFY_ALL
+    );
+  });
+}
+
+add_task(async function test_URIAndDomainCounts() {
+  // Let's reset the counts.
+  Services.telemetry.clearScalars();
+
+  let checkCounts = countsObject => {
+    // Get a snapshot of the scalars and then clear them.
+    const scalars = TelemetryTestUtils.getProcessScalars("parent");
+    TelemetryTestUtils.assertScalar(
+      scalars,
+      TOTAL_URI_COUNT,
+      countsObject.totalURIs,
+      "The URI scalar must contain the expected value."
+    );
+    TelemetryTestUtils.assertScalar(
+      scalars,
+      UNIQUE_DOMAINS_COUNT,
+      countsObject.domainCount,
+      "The unique domains scalar must contain the expected value."
+    );
+    TelemetryTestUtils.assertScalar(
+      scalars,
+      UNFILTERED_URI_COUNT,
+      countsObject.totalUnfilteredURIs,
+      "The unfiltered URI scalar must contain the expected value."
+    );
+  };
+
+  // Check that about:blank doesn't get counted in the URI total.
+  let firstTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  TelemetryTestUtils.assertScalarUnset(
+    TelemetryTestUtils.getProcessScalars("parent"),
+    TOTAL_URI_COUNT
+  );
+  TelemetryTestUtils.assertScalarUnset(
+    TelemetryTestUtils.getProcessScalars("parent"),
+    UNIQUE_DOMAINS_COUNT
+  );
+  TelemetryTestUtils.assertScalarUnset(
+    TelemetryTestUtils.getProcessScalars("parent"),
+    UNFILTERED_URI_COUNT
+  );
+
+  // Open a different page and check the counts.
+  BrowserTestUtils.startLoadingURIString(
+    firstTab.linkedBrowser,
+    "http://example.com/"
+  );
+  await BrowserTestUtils.browserLoaded(firstTab.linkedBrowser);
+  checkCounts({ totalURIs: 1, domainCount: 1, totalUnfilteredURIs: 1 });
+
+  // Activating a different tab must not increase the URI count.
+  let secondTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  await BrowserTestUtils.switchTab(gBrowser, firstTab);
+  checkCounts({ totalURIs: 1, domainCount: 1, totalUnfilteredURIs: 1 });
+  BrowserTestUtils.removeTab(secondTab);
+
+  // Open a new window and set the tab to a new address.
+  let newWin = await BrowserTestUtils.openNewBrowserWindow();
+  BrowserTestUtils.startLoadingURIString(
+    newWin.gBrowser.selectedBrowser,
+    "http://example.com/"
+  );
+  await BrowserTestUtils.browserLoaded(newWin.gBrowser.selectedBrowser);
+  checkCounts({ totalURIs: 2, domainCount: 1, totalUnfilteredURIs: 2 });
+
+  // We should not count AJAX requests.
+  const XHR_URL = "http://example.com/r";
+  await SpecialPowers.spawn(
+    newWin.gBrowser.selectedBrowser,
+    [XHR_URL],
+    function (url) {
+      return new Promise(resolve => {
+        var xhr = new content.window.XMLHttpRequest();
+        xhr.open("GET", url);
+        xhr.onload = () => resolve();
+        xhr.send();
+      });
+    }
+  );
+  checkCounts({ totalURIs: 2, domainCount: 1, totalUnfilteredURIs: 2 });
+
+  // Check that we're counting page fragments.
+  let loadingStopped = browserLocationChanged(newWin.gBrowser.selectedBrowser);
+  BrowserTestUtils.startLoadingURIString(
+    newWin.gBrowser.selectedBrowser,
+    "http://example.com/#2"
+  );
+  await loadingStopped;
+  checkCounts({ totalURIs: 3, domainCount: 1, totalUnfilteredURIs: 3 });
+
+  // Check that a different URI from the example.com domain doesn't increment the unique count.
+  BrowserTestUtils.startLoadingURIString(
+    newWin.gBrowser.selectedBrowser,
+    "http://test1.example.com/"
+  );
+  await BrowserTestUtils.browserLoaded(newWin.gBrowser.selectedBrowser);
+  checkCounts({ totalURIs: 4, domainCount: 1, totalUnfilteredURIs: 4 });
+
+  // Make sure that the unique domains counter is incrementing for a different domain.
+  BrowserTestUtils.startLoadingURIString(
+    newWin.gBrowser.selectedBrowser,
+    "https://example.org/"
+  );
+  await BrowserTestUtils.browserLoaded(newWin.gBrowser.selectedBrowser);
+  checkCounts({ totalURIs: 5, domainCount: 2, totalUnfilteredURIs: 5 });
+
+  // Check that we only account for top level loads (e.g. we don't count URIs from
+  // embedded iframes).
+  await SpecialPowers.spawn(
+    newWin.gBrowser.selectedBrowser,
+    [],
+    async function () {
+      let doc = content.document;
+      let iframe = doc.createElement("iframe");
+      let promiseIframeLoaded = ContentTaskUtils.waitForEvent(
+        iframe,
+        "load",
+        false
+      );
+      iframe.src = "https://example.org/test";
+      doc.body.insertBefore(iframe, doc.body.firstElementChild);
+      await promiseIframeLoaded;
+    }
+  );
+  checkCounts({ totalURIs: 5, domainCount: 2, totalUnfilteredURIs: 5 });
+
+  // Check that uncommon protocols get counted in the unfiltered URI probe.
+  const TEST_PAGE =
+    "data:text/html,<a id='target' href='%23par1'>Click me</a><a name='par1'>The paragraph.</a>";
+  BrowserTestUtils.startLoadingURIString(
+    newWin.gBrowser.selectedBrowser,
+    TEST_PAGE
+  );
+  await BrowserTestUtils.browserLoaded(newWin.gBrowser.selectedBrowser);
+  checkCounts({ totalURIs: 5, domainCount: 2, totalUnfilteredURIs: 6 });
+
+  // Clean up.
+  BrowserTestUtils.removeTab(firstTab);
+  await BrowserTestUtils.closeWindow(newWin);
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry_interaction.js b/browser/modules/test/browser/browser_UsageTelemetry_interaction.js
new file mode 100644
index 0000000000..2bc60d9697
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry_interaction.js
@@ -0,0 +1,955 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+"use strict";
+
+gReduceMotionOverride = true;
+
+const AREAS = [
+  "keyboard",
+  "menu_bar",
+  "tabs_bar",
+  "nav_bar",
+  "bookmarks_bar",
+  "app_menu",
+  "tabs_context",
+  "content_context",
+  "overflow_menu",
+  "pinned_overflow_menu",
+  "pageaction_urlbar",
+  "pageaction_panel",
+
+  "preferences_paneHome",
+  "preferences_paneGeneral",
+  "preferences_panePrivacy",
+  "preferences_paneSearch",
+  "preferences_paneSearchResults",
+  "preferences_paneSync",
+  "preferences_paneContainers",
+];
+
+// Checks that the correct number of clicks are registered against the correct
+// keys in the scalars. Also runs keyed scalar checks against non-area types
+// passed in through expectedOther.
+function assertInteractionScalars(expectedAreas, expectedOther = {}) {
+  let processScalars =
+    Services.telemetry.getSnapshotForKeyedScalars("main", true)?.parent ?? {};
+
+  let compareSourceWithExpectations = (source, expected = {}) => {
+    let scalars = processScalars?.[`browser.ui.interaction.${source}`] ?? {};
+
+    let expectedKeys = new Set(
+      Object.keys(scalars).concat(Object.keys(expected))
+    );
+
+    for (let key of expectedKeys) {
+      Assert.equal(
+        scalars[key],
+        expected[key],
+        `Expected to see the correct value for ${key} in ${source}.`
+      );
+    }
+  };
+
+  for (let source of AREAS) {
+    compareSourceWithExpectations(source, expectedAreas[source]);
+  }
+
+  for (let source in expectedOther) {
+    compareSourceWithExpectations(source, expectedOther[source]);
+  }
+}
+
+const elem = id => document.getElementById(id);
+const click = el => {
+  if (typeof el == "string") {
+    el = elem(el);
+  }
+
+  EventUtils.synthesizeMouseAtCenter(el, {}, window);
+};
+
+add_task(async function toolbarButtons() {
+  await BrowserTestUtils.withNewTab("https://example.com", async () => {
+    let customButton = await new Promise(resolve => {
+      CustomizableUI.createWidget({
+        // In CSS identifiers cannot start with a number but CustomizableUI accepts that.
+        id: "12foo",
+        label: "12foo",
+        onCreated: resolve,
+        defaultArea: "nav-bar",
+      });
+    });
+
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    let newTab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+    let tabClose = BrowserTestUtils.waitForTabClosing(newTab);
+
+    let tabs = elem("tabbrowser-tabs");
+    if (!tabs.hasAttribute("overflow")) {
+      tabs.setAttribute("overflow", "true");
+      registerCleanupFunction(() => {
+        tabs.removeAttribute("overflow");
+      });
+    }
+
+    // We intentionally turn off a11y_checks for these click events, because the
+    // test is checking the telemetry functionality and the following 3 clicks
+    // are targeting disabled controls to test the changes in scalars (for more
+    // refer to the bug 1864576 comment 2 and bug 1854999 comment 4):
+    AccessibilityUtils.setEnv({
+      mustBeEnabled: false,
+    });
+    click("stop-reload-button");
+    click("back-button");
+    click("back-button");
+    AccessibilityUtils.resetEnv();
+
+    // Make sure the all tabs panel is in the document.
+    gTabsPanel.initElements();
+    let view = elem("allTabsMenu-allTabsView");
+    let shown = BrowserTestUtils.waitForEvent(view, "ViewShown");
+    click("alltabs-button");
+    await shown;
+
+    let hidden = BrowserTestUtils.waitForEvent(view, "ViewHiding");
+    gTabsPanel.hideAllTabsPanel();
+    await hidden;
+
+    click(newTab.querySelector(".tab-close-button"));
+    await tabClose;
+
+    let bookmarksToolbar = gNavToolbox.querySelector("#PersonalToolbar");
+
+    let bookmarksToolbarReady = BrowserTestUtils.waitForMutationCondition(
+      bookmarksToolbar,
+      { attributes: true },
+      () => {
+        return (
+          bookmarksToolbar.getAttribute("collapsed") != "true" &&
+          bookmarksToolbar.getAttribute("initialized") == "true"
+        );
+      }
+    );
+
+    window.setToolbarVisibility(
+      bookmarksToolbar,
+      true /* isVisible */,
+      false /* persist */,
+      false /* animated */
+    );
+    registerCleanupFunction(() => {
+      window.setToolbarVisibility(
+        bookmarksToolbar,
+        false /* isVisible */,
+        false /* persist */,
+        false /* animated */
+      );
+    });
+    await bookmarksToolbarReady;
+
+    // The Bookmarks Toolbar does some optimizations to try not to jank the
+    // browser when populating itself, and does so asynchronously. We wait
+    // until a bookmark item is available in the DOM before continuing.
+    let placesToolbarItems = document.getElementById("PlacesToolbarItems");
+    await BrowserTestUtils.waitForMutationCondition(
+      placesToolbarItems,
+      { childList: true },
+      () => placesToolbarItems.querySelector(".bookmark-item") != null
+    );
+
+    click(placesToolbarItems.querySelector(".bookmark-item"));
+
+    click(customButton);
+
+    assertInteractionScalars(
+      {
+        nav_bar: {
+          "stop-reload-button": 1,
+          "back-button": 2,
+          "12foo": 1,
+        },
+        tabs_bar: {
+          "alltabs-button": 1,
+          "tab-close-button": 1,
+        },
+        bookmarks_bar: {
+          "bookmark-item": 1,
+        },
+      },
+      {
+        all_tabs_panel_entrypoint: {
+          "alltabs-button": 1,
+        },
+      }
+    );
+    CustomizableUI.destroyWidget("12foo");
+  });
+});
+
+add_task(async function contextMenu() {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    let tab = gBrowser.getTabForBrowser(browser);
+    let context = elem("tabContextMenu");
+    let shown = BrowserTestUtils.waitForEvent(context, "popupshown");
+    EventUtils.synthesizeMouseAtCenter(
+      tab,
+      { type: "contextmenu", button: 2 },
+      window
+    );
+    await shown;
+
+    let hidden = BrowserTestUtils.waitForEvent(context, "popuphidden");
+    context.activateItem(document.getElementById("context_toggleMuteTab"));
+    await hidden;
+
+    assertInteractionScalars({
+      tabs_context: {
+        "context-toggleMuteTab": 1,
+      },
+    });
+
+    // Check that tab-related items in the toolbar menu also register telemetry:
+    context = elem("toolbar-context-menu");
+    shown = BrowserTestUtils.waitForEvent(context, "popupshown");
+    let scrollbox = elem("tabbrowser-arrowscrollbox");
+    EventUtils.synthesizeMouse(
+      scrollbox,
+      // offset within the scrollbox - somewhere near the end:
+      scrollbox.getBoundingClientRect().width - 20,
+      5,
+      { type: "contextmenu", button: 2 },
+      window
+    );
+    await shown;
+
+    hidden = BrowserTestUtils.waitForEvent(context, "popuphidden");
+    context.activateItem(
+      document.getElementById("toolbar-context-selectAllTabs")
+    );
+    await hidden;
+
+    assertInteractionScalars({
+      tabs_context: {
+        "toolbar-context-selectAllTabs": 1,
+      },
+    });
+    // tidy up:
+    gBrowser.clearMultiSelectedTabs();
+  });
+});
+
+add_task(async function contextMenu_entrypoints() {
+  /**
+   * A utility function for this test task that opens the tab context
+   * menu for a particular trigger node, chooses the "Reload Tab" item,
+   * and then waits for the context menu to close.
+   *
+   * @param {Element} triggerNode
+   *   The node that the tab context menu should be triggered with.
+   * @returns {Promise<undefined>}
+   *   Resolves after the context menu has fired the popuphidden event.
+   */
+  let openAndCloseTabContextMenu = async triggerNode => {
+    let contextMenu = document.getElementById("tabContextMenu");
+    let popupShown = BrowserTestUtils.waitForEvent(contextMenu, "popupshown");
+    EventUtils.synthesizeMouseAtCenter(triggerNode, {
+      type: "contextmenu",
+      button: 2,
+    });
+    await popupShown;
+
+    let popupHidden = BrowserTestUtils.waitForEvent(contextMenu, "popuphidden");
+    let menuitem = document.getElementById("context_reloadTab");
+    contextMenu.activateItem(menuitem);
+    await popupHidden;
+  };
+
+  const TAB_CONTEXTMENU_ENTRYPOINT_SCALAR =
+    "browser.ui.interaction.tabs_context_entrypoint";
+  Services.telemetry.clearScalars();
+
+  let scalars = TelemetryTestUtils.getProcessScalars("parent", true, true);
+  TelemetryTestUtils.assertScalarUnset(
+    scalars,
+    TAB_CONTEXTMENU_ENTRYPOINT_SCALAR
+  );
+
+  await openAndCloseTabContextMenu(gBrowser.selectedTab);
+  scalars = TelemetryTestUtils.getProcessScalars("parent", true, true);
+  TelemetryTestUtils.assertKeyedScalar(
+    scalars,
+    TAB_CONTEXTMENU_ENTRYPOINT_SCALAR,
+    "tabs-bar",
+    1
+  );
+
+  gTabsPanel.initElements();
+  let allTabsView = document.getElementById("allTabsMenu-allTabsView");
+  let allTabsPopupShownPromise = BrowserTestUtils.waitForEvent(
+    allTabsView,
+    "ViewShown"
+  );
+  gTabsPanel.showAllTabsPanel(null);
+  await allTabsPopupShownPromise;
+
+  let firstTabItem = gTabsPanel.allTabsViewTabs.children[0];
+  await openAndCloseTabContextMenu(firstTabItem);
+  scalars = TelemetryTestUtils.getProcessScalars("parent", true, true);
+  TelemetryTestUtils.assertKeyedScalar(
+    scalars,
+    TAB_CONTEXTMENU_ENTRYPOINT_SCALAR,
+    "alltabs-menu",
+    1
+  );
+
+  let allTabsPopupHiddenPromise = BrowserTestUtils.waitForEvent(
+    allTabsView.panelMultiView,
+    "PanelMultiViewHidden"
+  );
+  gTabsPanel.hideAllTabsPanel();
+  await allTabsPopupHiddenPromise;
+});
+
+add_task(async function appMenu() {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    let shown = BrowserTestUtils.waitForEvent(
+      elem("appMenu-popup"),
+      "popupshown"
+    );
+    click("PanelUI-menu-button");
+    await shown;
+
+    let hidden = BrowserTestUtils.waitForEvent(
+      elem("appMenu-popup"),
+      "popuphidden"
+    );
+
+    let findButtonID = "appMenu-find-button2";
+    click(findButtonID);
+    await hidden;
+
+    let expectedScalars = {
+      nav_bar: {
+        "PanelUI-menu-button": 1,
+      },
+      app_menu: {},
+    };
+    expectedScalars.app_menu[findButtonID] = 1;
+
+    assertInteractionScalars(expectedScalars);
+  });
+});
+
+add_task(async function devtools() {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    let shown = BrowserTestUtils.waitForEvent(
+      elem("appMenu-popup"),
+      "popupshown"
+    );
+    click("PanelUI-menu-button");
+    await shown;
+
+    click("appMenu-more-button2");
+    shown = BrowserTestUtils.waitForEvent(
+      elem("appmenu-moreTools"),
+      "ViewShown"
+    );
+    await shown;
+
+    let tabOpen = BrowserTestUtils.waitForNewTab(gBrowser);
+    let hidden = BrowserTestUtils.waitForEvent(
+      elem("appMenu-popup"),
+      "popuphidden"
+    );
+    click(
+      document.querySelector(
+        "#appmenu-moreTools toolbarbutton[key='key_viewSource']"
+      )
+    );
+    await hidden;
+
+    let tab = await tabOpen;
+    BrowserTestUtils.removeTab(tab);
+
+    // Note that item ID's have '_' converted to '-'.
+    assertInteractionScalars({
+      nav_bar: {
+        "PanelUI-menu-button": 1,
+      },
+      app_menu: {
+        "appMenu-more-button2": 1,
+        "key-viewSource": 1,
+      },
+    });
+  });
+});
+
+add_task(async function webextension() {
+  BrowserUsageTelemetry._resetAddonIds();
+
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    function background() {
+      browser.commands.onCommand.addListener(() => {
+        browser.test.sendMessage("oncommand");
+      });
+
+      browser.runtime.onMessage.addListener(msg => {
+        if (msg == "from-sidebar-action") {
+          browser.test.sendMessage("sidebar-opened");
+        }
+      });
+
+      browser.test.sendMessage("ready");
+    }
+
+    const extension = ExtensionTestUtils.loadExtension({
+      manifest: {
+        version: "1",
+        browser_specific_settings: {
+          gecko: { id: "random_addon@example.com" },
+        },
+        browser_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+          default_area: "navbar",
+        },
+        page_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+          show_matches: ["https://example.com/*"],
+        },
+        commands: {
+          test_command: {
+            suggested_key: {
+              default: "Alt+Shift+J",
+            },
+          },
+          _execute_sidebar_action: {
+            suggested_key: {
+              default: "Alt+Shift+Q",
+            },
+          },
+        },
+        sidebar_action: {
+          default_panel: "sidebar.html",
+          open_at_install: false,
+        },
+      },
+      files: {
+        "sidebar.html": `
+          <!DOCTYPE html>
+          <html>
+            <head>
+              <meta charset="utf-8">
+              <script src="sidebar.js"></script>
+            </head>
+          </html>
+        `,
+
+        "sidebar.js": function () {
+          browser.runtime.sendMessage("from-sidebar-action");
+        },
+      },
+      background,
+    });
+
+    await extension.startup();
+    await extension.awaitMessage("ready");
+
+    // As the first add-on interacted with this should show up as `addon0`.
+
+    click("random_addon_example_com-browser-action");
+    assertInteractionScalars({
+      nav_bar: {
+        addon0: 1,
+      },
+    });
+
+    // Wait for the element to show up.
+    await TestUtils.waitForCondition(() =>
+      elem("pageAction-urlbar-random_addon_example_com")
+    );
+
+    click("pageAction-urlbar-random_addon_example_com");
+    assertInteractionScalars({
+      pageaction_urlbar: {
+        addon0: 1,
+      },
+    });
+
+    EventUtils.synthesizeKey("j", { altKey: true, shiftKey: true });
+    await extension.awaitMessage("oncommand");
+    assertInteractionScalars({
+      keyboard: {
+        addon0: 1,
+      },
+    });
+
+    EventUtils.synthesizeKey("q", { altKey: true, shiftKey: true });
+    await extension.awaitMessage("sidebar-opened");
+    assertInteractionScalars({
+      keyboard: {
+        addon0: 1,
+      },
+    });
+
+    const extension2 = ExtensionTestUtils.loadExtension({
+      manifest: {
+        version: "1",
+        browser_specific_settings: {
+          gecko: { id: "random_addon2@example.com" },
+        },
+        browser_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+          default_area: "navbar",
+        },
+        page_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+          show_matches: ["https://example.com/*"],
+        },
+        commands: {
+          test_command: {
+            suggested_key: {
+              default: "Alt+Shift+9",
+            },
+          },
+        },
+      },
+      background,
+    });
+
+    await extension2.startup();
+    await extension2.awaitMessage("ready");
+
+    // A second extension should be `addon1`.
+
+    click("random_addon2_example_com-browser-action");
+    assertInteractionScalars({
+      nav_bar: {
+        addon1: 1,
+      },
+    });
+
+    // Wait for the element to show up.
+    await TestUtils.waitForCondition(() =>
+      elem("pageAction-urlbar-random_addon2_example_com")
+    );
+
+    click("pageAction-urlbar-random_addon2_example_com");
+    assertInteractionScalars({
+      pageaction_urlbar: {
+        addon1: 1,
+      },
+    });
+
+    EventUtils.synthesizeKey("9", { altKey: true, shiftKey: true });
+    await extension2.awaitMessage("oncommand");
+    assertInteractionScalars({
+      keyboard: {
+        addon1: 1,
+      },
+    });
+
+    // The first should have retained its ID.
+    click("random_addon_example_com-browser-action");
+    assertInteractionScalars({
+      nav_bar: {
+        addon0: 1,
+      },
+    });
+
+    EventUtils.synthesizeKey("j", { altKey: true, shiftKey: true });
+    await extension.awaitMessage("oncommand");
+    assertInteractionScalars({
+      keyboard: {
+        addon0: 1,
+      },
+    });
+
+    click("pageAction-urlbar-random_addon_example_com");
+    assertInteractionScalars({
+      pageaction_urlbar: {
+        addon0: 1,
+      },
+    });
+
+    await extension.unload();
+
+    // Clear the last opened ID so if this test runs again the sidebar won't
+    // automatically open when the extension is installed.
+    window.SidebarUI.lastOpenedId = null;
+
+    // The second should retain its ID.
+    click("random_addon2_example_com-browser-action");
+    click("random_addon2_example_com-browser-action");
+    assertInteractionScalars({
+      nav_bar: {
+        addon1: 2,
+      },
+    });
+
+    click("pageAction-urlbar-random_addon2_example_com");
+    assertInteractionScalars({
+      pageaction_urlbar: {
+        addon1: 1,
+      },
+    });
+
+    EventUtils.synthesizeKey("9", { altKey: true, shiftKey: true });
+    await extension2.awaitMessage("oncommand");
+    assertInteractionScalars({
+      keyboard: {
+        addon1: 1,
+      },
+    });
+
+    await extension2.unload();
+
+    // Now test that browser action items in the add-ons panel also get
+    // telemetry recorded for them.
+    const extension3 = ExtensionTestUtils.loadExtension({
+      manifest: {
+        version: "1",
+        browser_specific_settings: {
+          gecko: { id: "random_addon3@example.com" },
+        },
+        browser_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+        },
+      },
+    });
+
+    await extension3.startup();
+
+    const shown = BrowserTestUtils.waitForPopupEvent(
+      gUnifiedExtensions.panel,
+      "shown"
+    );
+    await gUnifiedExtensions.togglePanel();
+    await shown;
+
+    click("random_addon3_example_com-browser-action");
+    assertInteractionScalars({
+      unified_extensions_area: {
+        addon2: 1,
+      },
+    });
+    const hidden = BrowserTestUtils.waitForPopupEvent(
+      gUnifiedExtensions.panel,
+      "hidden"
+    );
+    await gUnifiedExtensions.panel.hidePopup();
+    await hidden;
+
+    await extension3.unload();
+  });
+});
+
+add_task(async function mainMenu() {
+  // macOS does not use the menu bar.
+  if (AppConstants.platform == "macosx") {
+    return;
+  }
+
+  BrowserUsageTelemetry._resetAddonIds();
+
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    CustomizableUI.setToolbarVisibility("toolbar-menubar", true);
+
+    let shown = BrowserTestUtils.waitForEvent(
+      elem("menu_EditPopup"),
+      "popupshown"
+    );
+    click("edit-menu");
+    await shown;
+
+    let hidden = BrowserTestUtils.waitForEvent(
+      elem("menu_EditPopup"),
+      "popuphidden"
+    );
+    click("menu_selectAll");
+    await hidden;
+
+    assertInteractionScalars({
+      menu_bar: {
+        // Note that the _ is replaced with - for telemetry identifiers.
+        "menu-selectAll": 1,
+      },
+    });
+
+    CustomizableUI.setToolbarVisibility("toolbar-menubar", false);
+  });
+});
+
+add_task(async function preferences() {
+  let finalPaneEvent = Services.prefs.getBoolPref("identity.fxaccounts.enabled")
+    ? "sync-pane-loaded"
+    : "privacy-pane-loaded";
+  let finalPrefPaneLoaded = TestUtils.topicObserved(finalPaneEvent, () => true);
+  await BrowserTestUtils.withNewTab("about:preferences", async browser => {
+    await finalPrefPaneLoaded;
+
+    Services.telemetry.getSnapshotForKeyedScalars("main", true);
+
+    await BrowserTestUtils.synthesizeMouseAtCenter(
+      "#browserRestoreSession",
+      {},
+      gBrowser.selectedBrowser.browsingContext
+    );
+
+    await BrowserTestUtils.synthesizeMouseAtCenter(
+      "#category-search",
+      {},
+      gBrowser.selectedBrowser.browsingContext
+    );
+
+    await BrowserTestUtils.synthesizeMouseAtCenter(
+      "#category-privacy",
+      {},
+      gBrowser.selectedBrowser.browsingContext
+    );
+    await BrowserTestUtils.waitForCondition(() =>
+      gBrowser.selectedBrowser.contentDocument.getElementById(
+        "contentBlockingLearnMore"
+      )
+    );
+
+    const onLearnMoreOpened = BrowserTestUtils.waitForNewTab(gBrowser);
+    gBrowser.selectedBrowser.contentDocument
+      .getElementById("contentBlockingLearnMore")
+      .scrollIntoView();
+    await BrowserTestUtils.synthesizeMouseAtCenter(
+      "#contentBlockingLearnMore",
+      {},
+      gBrowser.selectedBrowser.browsingContext
+    );
+    await onLearnMoreOpened;
+    gBrowser.removeCurrentTab();
+
+    assertInteractionScalars({
+      preferences_paneGeneral: {
+        browserRestoreSession: 1,
+      },
+      preferences_panePrivacy: {
+        contentBlockingLearnMore: 1,
+      },
+    });
+  });
+});
+
+/**
+ * Context click on a history or bookmark link and open it in a new window.
+ *
+ * @param {Element} link - The link to open.
+ */
+async function openLinkUsingContextMenu(link) {
+  const placesContext = document.getElementById("placesContext");
+  const promisePopup = BrowserTestUtils.waitForEvent(
+    placesContext,
+    "popupshown"
+  );
+  EventUtils.synthesizeMouseAtCenter(link, {
+    button: 2,
+    type: "contextmenu",
+  });
+  await promisePopup;
+  const promiseNewWindow = BrowserTestUtils.waitForNewWindow();
+  placesContext.activateItem(
+    document.getElementById("placesContext_open:newwindow")
+  );
+  const win = await promiseNewWindow;
+  await BrowserTestUtils.closeWindow(win);
+}
+
+async function history_appMenu(useContextClick) {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    let shown = BrowserTestUtils.waitForEvent(
+      elem("appMenu-popup"),
+      "popupshown"
+    );
+    click("PanelUI-menu-button");
+    await shown;
+
+    click("appMenu-history-button");
+    shown = BrowserTestUtils.waitForEvent(elem("PanelUI-history"), "ViewShown");
+    await shown;
+
+    let list = document.getElementById("appMenu_historyMenu");
+    let listItem = list.querySelector("toolbarbutton");
+
+    if (useContextClick) {
+      await openLinkUsingContextMenu(listItem);
+    } else {
+      EventUtils.synthesizeMouseAtCenter(listItem, {});
+    }
+
+    let expectedScalars = {
+      nav_bar: {
+        "PanelUI-menu-button": 1,
+      },
+
+      app_menu: { "history-item": 1, "appMenu-history-button": 1 },
+    };
+    assertInteractionScalars(expectedScalars);
+  });
+}
+
+add_task(async function history_appMenu_click() {
+  await history_appMenu(false);
+});
+
+add_task(async function history_appMenu_context_click() {
+  await history_appMenu(true);
+});
+
+async function bookmarks_appMenu(useContextClick) {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    let shown = BrowserTestUtils.waitForEvent(
+      elem("appMenu-popup"),
+      "popupshown"
+    );
+
+    shown = BrowserTestUtils.waitForEvent(elem("appMenu-popup"), "popupshown");
+    click("PanelUI-menu-button");
+    await shown;
+
+    click("appMenu-bookmarks-button");
+    shown = BrowserTestUtils.waitForEvent(
+      elem("PanelUI-bookmarks"),
+      "ViewShown"
+    );
+    await shown;
+
+    let list = document.getElementById("panelMenu_bookmarksMenu");
+    let listItem = list.querySelector("toolbarbutton");
+
+    if (useContextClick) {
+      await openLinkUsingContextMenu(listItem);
+    } else {
+      EventUtils.synthesizeMouseAtCenter(listItem, {});
+    }
+
+    let expectedScalars = {
+      nav_bar: {
+        "PanelUI-menu-button": 1,
+      },
+
+      app_menu: { "bookmark-item": 1, "appMenu-bookmarks-button": 1 },
+    };
+    assertInteractionScalars(expectedScalars);
+  });
+}
+
+add_task(async function bookmarks_appMenu_click() {
+  await bookmarks_appMenu(false);
+});
+
+add_task(async function bookmarks_appMenu_context_click() {
+  await bookmarks_appMenu(true);
+});
+
+async function bookmarks_library_navbar(useContextClick) {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    CustomizableUI.addWidgetToArea("library-button", "nav-bar");
+    let button = document.getElementById("library-button");
+    button.click();
+    await BrowserTestUtils.waitForEvent(
+      elem("appMenu-libraryView"),
+      "ViewShown"
+    );
+
+    click("appMenu-library-bookmarks-button");
+    await BrowserTestUtils.waitForEvent(elem("PanelUI-bookmarks"), "ViewShown");
+
+    let list = document.getElementById("panelMenu_bookmarksMenu");
+    let listItem = list.querySelector("toolbarbutton");
+
+    if (useContextClick) {
+      await openLinkUsingContextMenu(listItem);
+    } else {
+      EventUtils.synthesizeMouseAtCenter(listItem, {});
+    }
+
+    let expectedScalars = {
+      nav_bar: {
+        "library-button": 1,
+        "bookmark-item": 1,
+        "appMenu-library-bookmarks-button": 1,
+      },
+    };
+    assertInteractionScalars(expectedScalars);
+  });
+
+  CustomizableUI.removeWidgetFromArea("library-button");
+}
+
+add_task(async function bookmarks_library_navbar_click() {
+  await bookmarks_library_navbar(false);
+});
+
+add_task(async function bookmarks_library_navbar_context_click() {
+  await bookmarks_library_navbar(true);
+});
+
+async function history_library_navbar(useContextClick) {
+  await BrowserTestUtils.withNewTab("https://example.com", async browser => {
+    CustomizableUI.addWidgetToArea("library-button", "nav-bar");
+    let button = document.getElementById("library-button");
+    button.click();
+    await BrowserTestUtils.waitForEvent(
+      elem("appMenu-libraryView"),
+      "ViewShown"
+    );
+
+    click("appMenu-library-history-button");
+    let shown = BrowserTestUtils.waitForEvent(
+      elem("PanelUI-history"),
+      "ViewShown"
+    );
+    await shown;
+
+    let list = document.getElementById("appMenu_historyMenu");
+    let listItem = list.querySelector("toolbarbutton");
+
+    if (useContextClick) {
+      await openLinkUsingContextMenu(listItem);
+    } else {
+      EventUtils.synthesizeMouseAtCenter(listItem, {});
+    }
+
+    let expectedScalars = {
+      nav_bar: {
+        "library-button": 1,
+        "history-item": 1,
+        "appMenu-library-history-button": 1,
+      },
+    };
+    assertInteractionScalars(expectedScalars);
+  });
+
+  CustomizableUI.removeWidgetFromArea("library-button");
+}
+
+add_task(async function history_library_navbar_click() {
+  await history_library_navbar(false);
+});
+
+add_task(async function history_library_navbar_context_click() {
+  await history_library_navbar(true);
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry_private_and_restore.js b/browser/modules/test/browser/browser_UsageTelemetry_private_and_restore.js
new file mode 100644
index 0000000000..89222739be
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry_private_and_restore.js
@@ -0,0 +1,164 @@
+"use strict";
+
+const triggeringPrincipal_base64 = E10SUtils.SERIALIZED_SYSTEMPRINCIPAL;
+
+const MAX_CONCURRENT_TABS = "browser.engagement.max_concurrent_tab_count";
+const TAB_EVENT_COUNT = "browser.engagement.tab_open_event_count";
+const MAX_CONCURRENT_WINDOWS = "browser.engagement.max_concurrent_window_count";
+const WINDOW_OPEN_COUNT = "browser.engagement.window_open_event_count";
+const TOTAL_URI_COUNT = "browser.engagement.total_uri_count";
+const UNFILTERED_URI_COUNT = "browser.engagement.unfiltered_uri_count";
+const UNIQUE_DOMAINS_COUNT = "browser.engagement.unique_domains_count";
+const TOTAL_URI_COUNT_NORMAL_AND_PRIVATE_MODE =
+  "browser.engagement.total_uri_count_normal_and_private_mode";
+
+BrowserUsageTelemetry._onTabsOpenedTask._timeoutMs = 0;
+registerCleanupFunction(() => {
+  BrowserUsageTelemetry._onTabsOpenedTask._timeoutMs = undefined;
+});
+
+function promiseBrowserStateRestored() {
+  return new Promise(resolve => {
+    Services.obs.addObserver(function observer(aSubject, aTopic) {
+      Services.obs.removeObserver(
+        observer,
+        "sessionstore-browser-state-restored"
+      );
+      resolve();
+    }, "sessionstore-browser-state-restored");
+  });
+}
+
+add_task(async function test_privateMode() {
+  // Let's reset the counts.
+  Services.telemetry.clearScalars();
+  Services.fog.testResetFOG();
+
+  // Open a private window and load a website in it.
+  let privateWin = await BrowserTestUtils.openNewBrowserWindow({
+    private: true,
+  });
+  await BrowserTestUtils.firstBrowserLoaded(privateWin);
+  BrowserTestUtils.startLoadingURIString(
+    privateWin.gBrowser.selectedBrowser,
+    "https://example.com/"
+  );
+  await BrowserTestUtils.browserLoaded(
+    privateWin.gBrowser.selectedBrowser,
+    false,
+    "https://example.com/"
+  );
+
+  // Check that tab and window count is recorded.
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  ok(
+    !(TOTAL_URI_COUNT in scalars),
+    "We should not track URIs in private mode."
+  );
+  ok(
+    !(UNFILTERED_URI_COUNT in scalars),
+    "We should not track URIs in private mode."
+  );
+  ok(
+    !(UNIQUE_DOMAINS_COUNT in scalars),
+    "We should not track unique domains in private mode."
+  );
+  is(
+    scalars[TAB_EVENT_COUNT],
+    1,
+    "The number of open tab event count must match the expected value."
+  );
+  is(
+    scalars[MAX_CONCURRENT_TABS],
+    2,
+    "The maximum tab count must match the expected value."
+  );
+  is(
+    scalars[WINDOW_OPEN_COUNT],
+    1,
+    "The number of window open event count must match the expected value."
+  );
+  is(
+    scalars[MAX_CONCURRENT_WINDOWS],
+    2,
+    "The maximum window count must match the expected value."
+  );
+  is(
+    scalars[TOTAL_URI_COUNT_NORMAL_AND_PRIVATE_MODE],
+    1,
+    "We should include URIs in private mode as part of the actual total URI count."
+  );
+  is(
+    Glean.browserEngagement.uriCount.testGetValue(),
+    1,
+    "We should record the URI count in Glean as well."
+  );
+
+  // Clean up.
+  await BrowserTestUtils.closeWindow(privateWin);
+});
+
+add_task(async function test_sessionRestore() {
+  const PREF_RESTORE_ON_DEMAND = "browser.sessionstore.restore_on_demand";
+  Services.prefs.setBoolPref(PREF_RESTORE_ON_DEMAND, false);
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref(PREF_RESTORE_ON_DEMAND);
+  });
+
+  // Let's reset the counts.
+  Services.telemetry.clearScalars();
+
+  // The first window will be put into the already open window and the second
+  // window will be opened with _openWindowWithState, which is the source of the problem.
+  const state = {
+    windows: [
+      {
+        tabs: [
+          {
+            entries: [
+              { url: "http://example.org", triggeringPrincipal_base64 },
+            ],
+            extData: { uniq: 3785 },
+          },
+        ],
+        selected: 1,
+      },
+    ],
+  };
+
+  // Save the current session.
+  let { SessionStore } = ChromeUtils.importESModule(
+    "resource:///modules/sessionstore/SessionStore.sys.mjs"
+  );
+
+  // Load the custom state and wait for SSTabRestored, as we want to make sure
+  // that the URI counting code was hit.
+  let tabRestored = BrowserTestUtils.waitForEvent(
+    gBrowser.tabContainer,
+    "SSTabRestored"
+  );
+  SessionStore.setBrowserState(JSON.stringify(state));
+  await tabRestored;
+
+  // Check that the URI is not recorded.
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  ok(
+    !(TOTAL_URI_COUNT in scalars),
+    "We should not track URIs from restored sessions."
+  );
+  ok(
+    !(UNFILTERED_URI_COUNT in scalars),
+    "We should not track URIs from restored sessions."
+  );
+  ok(
+    !(UNIQUE_DOMAINS_COUNT in scalars),
+    "We should not track unique domains from restored sessions."
+  );
+
+  // Restore the original session and cleanup.
+  let sessionRestored = promiseBrowserStateRestored();
+  SessionStore.setBrowserState(JSON.stringify(state));
+  await sessionRestored;
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry_toolbars.js b/browser/modules/test/browser/browser_UsageTelemetry_toolbars.js
new file mode 100644
index 0000000000..aade03ec84
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry_toolbars.js
@@ -0,0 +1,550 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+"use strict";
+
+gReduceMotionOverride = true;
+
+function enterCustomizationMode(win = window) {
+  let customizationReadyPromise = BrowserTestUtils.waitForEvent(
+    win.gNavToolbox,
+    "customizationready"
+  );
+  win.gCustomizeMode.enter();
+  return customizationReadyPromise;
+}
+
+function leaveCustomizationMode(win = window) {
+  let customizationDonePromise = BrowserTestUtils.waitForEvent(
+    win.gNavToolbox,
+    "aftercustomization"
+  );
+  win.gCustomizeMode.exit();
+  return customizationDonePromise;
+}
+
+Services.prefs.setBoolPref("browser.uiCustomization.skipSourceNodeCheck", true);
+registerCleanupFunction(() => {
+  CustomizableUI.reset();
+  Services.prefs.clearUserPref("browser.uiCustomization.skipSourceNodeCheck");
+});
+
+// Stolen from browser/components/customizableui/tests/browser/head.js
+function simulateItemDrag(aToDrag, aTarget, aEvent = {}, aOffset = 2) {
+  let ev = aEvent;
+  if (ev == "end" || ev == "start") {
+    let win = aTarget.ownerGlobal;
+    const dwu = win.windowUtils;
+    let bounds = dwu.getBoundsWithoutFlushing(aTarget);
+    if (ev == "end") {
+      ev = {
+        clientX: bounds.right - aOffset,
+        clientY: bounds.bottom - aOffset,
+      };
+    } else {
+      ev = { clientX: bounds.left + aOffset, clientY: bounds.top + aOffset };
+    }
+  }
+  ev._domDispatchOnly = true;
+  EventUtils.synthesizeDrop(
+    aToDrag.parentNode,
+    aTarget,
+    null,
+    null,
+    aToDrag.ownerGlobal,
+    aTarget.ownerGlobal,
+    ev
+  );
+  // Ensure dnd suppression is cleared.
+  EventUtils.synthesizeMouseAtCenter(
+    aTarget,
+    { type: "mouseup" },
+    aTarget.ownerGlobal
+  );
+}
+
+function organizeToolbars(state = {}) {
+  // Set up the defaults for the state.
+  let targetState = Object.assign(
+    {
+      // Areas where widgets can be placed, set to an array of widget IDs.
+      "toolbar-menubar": undefined,
+      PersonalToolbar: undefined,
+      TabsToolbar: ["tabbrowser-tabs", "alltabs-button"],
+      "widget-overflow-fixed-list": undefined,
+      "nav-bar": ["back-button", "forward-button", "urlbar-container"],
+
+      // The page action's that should be in the URL bar.
+      pageActionsInUrlBar: [],
+
+      // Areas to show or hide.
+      titlebarVisible: false,
+      menubarVisible: false,
+      personalToolbarVisible: false,
+    },
+    state
+  );
+
+  for (let area of CustomizableUI.areas) {
+    // Clear out anything there already.
+    for (let widgetId of CustomizableUI.getWidgetIdsInArea(area)) {
+      CustomizableUI.removeWidgetFromArea(widgetId);
+    }
+
+    if (targetState[area]) {
+      // We specify the position explicitly to support the toolbars that have
+      // fixed widgets.
+      let position = 0;
+      for (let widgetId of targetState[area]) {
+        CustomizableUI.addWidgetToArea(widgetId, area, position++);
+      }
+    }
+  }
+
+  CustomizableUI.setToolbarVisibility(
+    "toolbar-menubar",
+    targetState.menubarVisible
+  );
+  CustomizableUI.setToolbarVisibility(
+    "PersonalToolbar",
+    targetState.personalToolbarVisible
+  );
+
+  Services.prefs.setIntPref(
+    "browser.tabs.inTitlebar",
+    !targetState.titlebarVisible
+  );
+
+  for (let action of PageActions.actions) {
+    action.pinnedToUrlbar = targetState.pageActionsInUrlBar.includes(action.id);
+  }
+
+  // Clear out the existing telemetry.
+  Services.telemetry.getSnapshotForKeyedScalars("main", true);
+}
+
+function assertVisibilityScalars(expected) {
+  let scalars =
+    Services.telemetry.getSnapshotForKeyedScalars("main", true)?.parent?.[
+      "browser.ui.toolbar_widgets"
+    ] ?? {};
+
+  // Only some platforms have the menubar items.
+  if (AppConstants.MENUBAR_CAN_AUTOHIDE) {
+    expected.push("menubar-items_pinned_menu-bar");
+  }
+
+  let keys = new Set(expected.concat(Object.keys(scalars)));
+  for (let key of keys) {
+    Assert.ok(expected.includes(key), `Scalar key ${key} was unexpected.`);
+    Assert.ok(scalars[key], `Expected to see see scalar key ${key} be true.`);
+  }
+}
+
+function assertCustomizeScalars(expected) {
+  let scalars =
+    Services.telemetry.getSnapshotForKeyedScalars("main", true)?.parent?.[
+      "browser.ui.customized_widgets"
+    ] ?? {};
+
+  let keys = new Set(Object.keys(expected).concat(Object.keys(scalars)));
+  for (let key of keys) {
+    Assert.equal(
+      scalars[key],
+      expected[key],
+      `Expected to see the correct value for scalar ${key}.`
+    );
+  }
+}
+
+add_task(async function widgetPositions() {
+  organizeToolbars();
+
+  BrowserUsageTelemetry._recordUITelemetry();
+
+  assertVisibilityScalars([
+    "menu-toolbar_pinned_off",
+    "titlebar_pinned_off",
+    "bookmarks-bar_pinned_off",
+
+    "tabbrowser-tabs_pinned_tabs-bar",
+    "alltabs-button_pinned_tabs-bar",
+    "unified-extensions-button_pinned_nav-bar-end",
+
+    "forward-button_pinned_nav-bar-start",
+    "back-button_pinned_nav-bar-start",
+  ]);
+
+  organizeToolbars({
+    PersonalToolbar: [
+      "fxa-toolbar-menu-button",
+      "new-tab-button",
+      "developer-button",
+    ],
+
+    TabsToolbar: [
+      "stop-reload-button",
+      "tabbrowser-tabs",
+      "personal-bookmarks",
+    ],
+
+    "nav-bar": [
+      "home-button",
+      "forward-button",
+      "downloads-button",
+      "urlbar-container",
+      "back-button",
+      "library-button",
+    ],
+
+    personalToolbarVisible: true,
+  });
+
+  BrowserUsageTelemetry._recordUITelemetry();
+
+  assertVisibilityScalars([
+    "menu-toolbar_pinned_off",
+    "titlebar_pinned_off",
+    "bookmarks-bar_pinned_on",
+
+    "tabbrowser-tabs_pinned_tabs-bar",
+    "stop-reload-button_pinned_tabs-bar",
+    "personal-bookmarks_pinned_tabs-bar",
+    "alltabs-button_pinned_tabs-bar",
+
+    "home-button_pinned_nav-bar-start",
+    "forward-button_pinned_nav-bar-start",
+    "downloads-button_pinned_nav-bar-start",
+    "back-button_pinned_nav-bar-end",
+    "library-button_pinned_nav-bar-end",
+    "unified-extensions-button_pinned_nav-bar-end",
+
+    "fxa-toolbar-menu-button_pinned_bookmarks-bar",
+    "new-tab-button_pinned_bookmarks-bar",
+    "developer-button_pinned_bookmarks-bar",
+  ]);
+
+  CustomizableUI.reset();
+});
+
+add_task(async function customizeMode() {
+  // Create a default state.
+  organizeToolbars({
+    PersonalToolbar: ["personal-bookmarks"],
+
+    TabsToolbar: ["tabbrowser-tabs", "new-tab-button"],
+
+    "nav-bar": [
+      "back-button",
+      "forward-button",
+      "stop-reload-button",
+      "urlbar-container",
+      "home-button",
+      "library-button",
+    ],
+  });
+
+  BrowserUsageTelemetry._recordUITelemetry();
+
+  assertVisibilityScalars([
+    "menu-toolbar_pinned_off",
+    "titlebar_pinned_off",
+    "bookmarks-bar_pinned_off",
+
+    "tabbrowser-tabs_pinned_tabs-bar",
+    "new-tab-button_pinned_tabs-bar",
+    "alltabs-button_pinned_tabs-bar",
+
+    "back-button_pinned_nav-bar-start",
+    "forward-button_pinned_nav-bar-start",
+    "stop-reload-button_pinned_nav-bar-start",
+    "home-button_pinned_nav-bar-end",
+    "library-button_pinned_nav-bar-end",
+    "unified-extensions-button_pinned_nav-bar-end",
+
+    "personal-bookmarks_pinned_bookmarks-bar",
+  ]);
+
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+
+  await enterCustomizationMode(win);
+
+  let toolbarButton = win.document.getElementById(
+    "customization-toolbar-visibility-button"
+  );
+  let toolbarPopup = win.document.getElementById("customization-toolbar-menu");
+  let popupShown = BrowserTestUtils.waitForEvent(toolbarPopup, "popupshown");
+  EventUtils.synthesizeMouseAtCenter(toolbarButton, {}, win);
+  await popupShown;
+
+  let barMenu = win.document.getElementById("toggle_PersonalToolbar");
+  let popupHidden = BrowserTestUtils.waitForEvent(toolbarPopup, "popuphidden");
+  let subMenu = barMenu.querySelector("menupopup");
+  popupShown = BrowserTestUtils.waitForEvent(subMenu, "popupshown");
+  EventUtils.synthesizeMouseAtCenter(barMenu, {}, win);
+  await popupShown;
+  let alwaysButton = barMenu.querySelector('*[data-visibility-enum="always"]');
+  EventUtils.synthesizeMouseAtCenter(alwaysButton, {}, win);
+  await popupHidden;
+
+  let navbar = CustomizableUI.getCustomizationTarget(
+    win.document.getElementById("nav-bar")
+  );
+  let bookmarksBar = CustomizableUI.getCustomizationTarget(
+    win.document.getElementById("PersonalToolbar")
+  );
+  let tabBar = CustomizableUI.getCustomizationTarget(
+    win.document.getElementById("TabsToolbar")
+  );
+
+  simulateItemDrag(win.document.getElementById("home-button"), navbar, "start");
+  simulateItemDrag(win.document.getElementById("library-button"), bookmarksBar);
+  simulateItemDrag(win.document.getElementById("stop-reload-button"), tabBar);
+  simulateItemDrag(
+    win.document.getElementById("stop-reload-button"),
+    navbar,
+    "start"
+  );
+  simulateItemDrag(win.document.getElementById("stop-reload-button"), tabBar);
+
+  await leaveCustomizationMode(win);
+
+  await BrowserTestUtils.closeWindow(win);
+
+  assertCustomizeScalars({
+    "home-button_move_nav-bar-end_nav-bar-start_drag": 1,
+    "library-button_move_nav-bar-end_bookmarks-bar_drag": 1,
+    "stop-reload-button_move_nav-bar-start_tabs-bar_drag": 2,
+    "stop-reload-button_move_tabs-bar_nav-bar-start_drag": 1,
+    "bookmarks-bar_move_off_always_customization-toolbar-menu": 1,
+  });
+
+  CustomizableUI.reset();
+});
+
+add_task(async function contextMenus() {
+  // Create a default state.
+  organizeToolbars({
+    PersonalToolbar: ["personal-bookmarks"],
+
+    TabsToolbar: ["tabbrowser-tabs", "new-tab-button"],
+
+    "nav-bar": [
+      "back-button",
+      "forward-button",
+      "stop-reload-button",
+      "urlbar-container",
+      "home-button",
+      "library-button",
+    ],
+  });
+
+  BrowserUsageTelemetry._recordUITelemetry();
+
+  assertVisibilityScalars([
+    "menu-toolbar_pinned_off",
+    "titlebar_pinned_off",
+    "bookmarks-bar_pinned_off",
+
+    "tabbrowser-tabs_pinned_tabs-bar",
+    "new-tab-button_pinned_tabs-bar",
+    "alltabs-button_pinned_tabs-bar",
+
+    "back-button_pinned_nav-bar-start",
+    "forward-button_pinned_nav-bar-start",
+    "stop-reload-button_pinned_nav-bar-start",
+    "home-button_pinned_nav-bar-end",
+    "library-button_pinned_nav-bar-end",
+    "unified-extensions-button_pinned_nav-bar-end",
+
+    "personal-bookmarks_pinned_bookmarks-bar",
+  ]);
+
+  let menu = document.getElementById("toolbar-context-menu");
+  let popupShown = BrowserTestUtils.waitForEvent(menu, "popupshown");
+  let button = document.getElementById("stop-reload-button");
+  EventUtils.synthesizeMouseAtCenter(
+    button,
+    { type: "contextmenu", button: 2 },
+    window
+  );
+  await popupShown;
+
+  let barMenu = document.getElementById("toggle_PersonalToolbar");
+  let popupHidden = BrowserTestUtils.waitForEvent(menu, "popuphidden");
+  let subMenu = barMenu.querySelector("menupopup");
+  popupShown = BrowserTestUtils.waitForEvent(subMenu, "popupshown");
+  barMenu.openMenu(true);
+  await popupShown;
+  let alwaysButton = subMenu.querySelector('*[data-visibility-enum="always"]');
+  subMenu.activateItem(alwaysButton);
+  await popupHidden;
+
+  popupShown = BrowserTestUtils.waitForEvent(menu, "popupshown");
+  EventUtils.synthesizeMouseAtCenter(
+    button,
+    { type: "contextmenu", button: 2 },
+    window
+  );
+  await popupShown;
+
+  popupHidden = BrowserTestUtils.waitForEvent(menu, "popuphidden");
+  let removeButton = document.querySelector(
+    "#toolbar-context-menu .customize-context-removeFromToolbar"
+  );
+  menu.activateItem(removeButton);
+  await popupHidden;
+
+  assertCustomizeScalars({
+    "bookmarks-bar_move_off_always_toolbar-context-menu": 1,
+    "stop-reload-button_remove_nav-bar-start_na_toolbar-context-menu": 1,
+  });
+
+  CustomizableUI.reset();
+});
+
+add_task(async function extensions() {
+  // The page action button is only visible when a page is loaded.
+  await BrowserTestUtils.withNewTab("http://example.com", async () => {
+    organizeToolbars();
+
+    const extension = ExtensionTestUtils.loadExtension({
+      useAddonManager: "temporary",
+      manifest: {
+        version: "1",
+        browser_specific_settings: {
+          gecko: { id: "random_addon@example.com" },
+        },
+        browser_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+          default_area: "navbar",
+        },
+        page_action: {
+          default_icon: "default.png",
+          default_title: "Hello",
+        },
+      },
+    });
+
+    await extension.startup();
+
+    assertCustomizeScalars({
+      "random-addon-example-com_add_na_nav-bar-end_addon": 1,
+      "random-addon-example-com_add_na_pageaction-urlbar_addon": 1,
+    });
+
+    BrowserUsageTelemetry._recordUITelemetry();
+
+    assertVisibilityScalars([
+      "menu-toolbar_pinned_off",
+      "titlebar_pinned_off",
+      "bookmarks-bar_pinned_off",
+
+      "tabbrowser-tabs_pinned_tabs-bar",
+      "alltabs-button_pinned_tabs-bar",
+
+      "forward-button_pinned_nav-bar-start",
+      "back-button_pinned_nav-bar-start",
+
+      "random-addon-example-com_pinned_nav-bar-end",
+      "unified-extensions-button_pinned_nav-bar-end",
+
+      "random-addon-example-com_pinned_pageaction-urlbar",
+    ]);
+
+    let addon = await AddonManager.getAddonByID(extension.id);
+    await addon.disable();
+
+    assertCustomizeScalars({
+      "random-addon-example-com_remove_nav-bar-end_na_addon": 1,
+      "random-addon-example-com_remove_pageaction-urlbar_na_addon": 1,
+    });
+
+    BrowserUsageTelemetry._recordUITelemetry();
+
+    assertVisibilityScalars([
+      "menu-toolbar_pinned_off",
+      "titlebar_pinned_off",
+      "bookmarks-bar_pinned_off",
+
+      "tabbrowser-tabs_pinned_tabs-bar",
+      "alltabs-button_pinned_tabs-bar",
+
+      "forward-button_pinned_nav-bar-start",
+      "back-button_pinned_nav-bar-start",
+      "unified-extensions-button_pinned_nav-bar-end",
+    ]);
+
+    await addon.enable();
+
+    assertCustomizeScalars({
+      "random-addon-example-com_add_na_nav-bar-end_addon": 1,
+      "random-addon-example-com_add_na_pageaction-urlbar_addon": 1,
+    });
+
+    BrowserUsageTelemetry._recordUITelemetry();
+
+    assertVisibilityScalars([
+      "menu-toolbar_pinned_off",
+      "titlebar_pinned_off",
+      "bookmarks-bar_pinned_off",
+
+      "tabbrowser-tabs_pinned_tabs-bar",
+      "alltabs-button_pinned_tabs-bar",
+
+      "forward-button_pinned_nav-bar-start",
+      "back-button_pinned_nav-bar-start",
+
+      "random-addon-example-com_pinned_nav-bar-end",
+      "unified-extensions-button_pinned_nav-bar-end",
+
+      "random-addon-example-com_pinned_pageaction-urlbar",
+    ]);
+
+    await addon.reload();
+
+    assertCustomizeScalars({});
+
+    await enterCustomizationMode();
+
+    let navbar = CustomizableUI.getCustomizationTarget(
+      document.getElementById("nav-bar")
+    );
+
+    simulateItemDrag(
+      document.getElementById("random_addon_example_com-browser-action"),
+      navbar,
+      "start"
+    );
+
+    await leaveCustomizationMode();
+
+    assertCustomizeScalars({
+      "random-addon-example-com_move_nav-bar-end_nav-bar-start_drag": 1,
+    });
+
+    await extension.unload();
+
+    assertCustomizeScalars({
+      "random-addon-example-com_remove_nav-bar-start_na_addon": 1,
+      "random-addon-example-com_remove_pageaction-urlbar_na_addon": 1,
+    });
+
+    BrowserUsageTelemetry._recordUITelemetry();
+
+    assertVisibilityScalars([
+      "menu-toolbar_pinned_off",
+      "titlebar_pinned_off",
+      "bookmarks-bar_pinned_off",
+
+      "tabbrowser-tabs_pinned_tabs-bar",
+      "alltabs-button_pinned_tabs-bar",
+
+      "forward-button_pinned_nav-bar-start",
+      "back-button_pinned_nav-bar-start",
+      "unified-extensions-button_pinned_nav-bar-end",
+    ]);
+  });
+});
diff --git a/browser/modules/test/browser/browser_UsageTelemetry_uniqueOriginsVisitedInPast24Hours.js b/browser/modules/test/browser/browser_UsageTelemetry_uniqueOriginsVisitedInPast24Hours.js
new file mode 100644
index 0000000000..11986f8e31
--- /dev/null
+++ b/browser/modules/test/browser/browser_UsageTelemetry_uniqueOriginsVisitedInPast24Hours.js
@@ -0,0 +1,87 @@
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+/* 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";
+
+ChromeUtils.defineESModuleGetters(this, {
+  URICountListener: "resource:///modules/BrowserUsageTelemetry.sys.mjs",
+});
+
+add_task(async function test_uniqueDomainsVisitedInPast24Hours() {
+  // By default, proxies don't apply to 127.0.0.1. We need them to for this test, though:
+  await SpecialPowers.pushPrefEnv({
+    set: [["network.proxy.allow_hijacking_localhost", true]],
+  });
+  registerCleanupFunction(async () => {
+    info("Cleaning up");
+    URICountListener.resetUniqueDomainsVisitedInPast24Hours();
+  });
+
+  URICountListener.resetUniqueDomainsVisitedInPast24Hours();
+  let startingCount = URICountListener.uniqueDomainsVisitedInPast24Hours;
+  is(
+    startingCount,
+    0,
+    "We should have no domains recorded in the history right after resetting"
+  );
+
+  // Add a new window and then some tabs in it.
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "http://example.com"
+  );
+
+  await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "http://test1.example.com"
+  );
+  is(
+    URICountListener.uniqueDomainsVisitedInPast24Hours,
+    startingCount + 1,
+    "test1.example.com should only count as a unique visit if example.com wasn't visited before"
+  );
+
+  await BrowserTestUtils.openNewForegroundTab(win.gBrowser, "http://127.0.0.1");
+  is(
+    URICountListener.uniqueDomainsVisitedInPast24Hours,
+    startingCount + 1,
+    "127.0.0.1 should not count as a unique visit"
+  );
+
+  // Set the expiry time to 4 seconds. The value should be reasonably short
+  // for testing, but long enough so that waiting for openNewForegroundTab
+  // does not cause the expiry timeout to run.
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.engagement.recent_visited_origins.expiry", 4]],
+  });
+
+  // http://www.exämple.test
+  await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "http://xn--exmple-cua.test"
+  );
+  is(
+    URICountListener.uniqueDomainsVisitedInPast24Hours,
+    startingCount + 2,
+    "www.exämple.test should count as a unique visit"
+  );
+
+  let countBefore = URICountListener.uniqueDomainsVisitedInPast24Hours;
+
+  // If expiration does not work correctly, the following will time out.
+  await BrowserTestUtils.waitForCondition(() => {
+    return (
+      URICountListener.uniqueDomainsVisitedInPast24Hours == countBefore - 1
+    );
+  }, 250);
+
+  let countAfter = URICountListener.uniqueDomainsVisitedInPast24Hours;
+  is(countAfter, countBefore - 1, "The expiry should work correctly");
+
+  BrowserTestUtils.removeTab(win.gBrowser.selectedTab);
+  BrowserTestUtils.removeTab(win.gBrowser.selectedTab);
+  await BrowserTestUtils.closeWindow(win);
+});
diff --git a/browser/modules/test/browser/browser_preloading_tab_moving.js b/browser/modules/test/browser/browser_preloading_tab_moving.js
new file mode 100644
index 0000000000..ce7cba9e85
--- /dev/null
+++ b/browser/modules/test/browser/browser_preloading_tab_moving.js
@@ -0,0 +1,150 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+var gOldCount = NewTabPagePreloading.MAX_COUNT;
+registerCleanupFunction(() => {
+  NewTabPagePreloading.MAX_COUNT = gOldCount;
+});
+
+async function openWinWithPreloadBrowser(options = {}) {
+  let idleFinishedPromise = TestUtils.topicObserved(
+    "browser-idle-startup-tasks-finished",
+    w => {
+      return w != window;
+    }
+  );
+  let newWin = await BrowserTestUtils.openNewBrowserWindow(options);
+  await idleFinishedPromise;
+  await TestUtils.waitForCondition(() => newWin.gBrowser.preloadedBrowser);
+  return newWin;
+}
+
+async function promiseNewTabLoadedInBrowser(browser) {
+  let url = browser.ownerGlobal.BROWSER_NEW_TAB_URL;
+  if (browser.currentURI.spec != url) {
+    info(`Waiting for ${url} to be the location for the browser.`);
+    await new Promise(resolve => {
+      let progressListener = {
+        onLocationChange(aWebProgress, aRequest, aLocationURI, aFlags) {
+          if (!url || aLocationURI.spec == url) {
+            browser.removeProgressListener(progressListener);
+            resolve();
+          }
+        },
+        QueryInterface: ChromeUtils.generateQI([
+          Ci.nsISupportsWeakReference,
+          Ci.nsIWebProgressListener2,
+          Ci.nsIWebProgressListener,
+        ]),
+      };
+      browser.addProgressListener(
+        progressListener,
+        Ci.nsIWebProgress.NOTIFY_ALL
+      );
+    });
+  } else {
+    info(`${url} already the current URI for the browser.`);
+  }
+
+  info(`Waiting for readyState complete in the browser`);
+  await SpecialPowers.spawn(browser, [], function () {
+    return ContentTaskUtils.waitForCondition(() => {
+      return content.document.readyState == "complete";
+    });
+  });
+}
+
+/**
+ * Verify that moving a preloaded browser's content from one window to the next
+ * works correctly.
+ */
+add_task(async function moving_works() {
+  NewTabPagePreloading.MAX_COUNT = 1;
+
+  NewTabPagePreloading.removePreloadedBrowser(window);
+
+  NewTabPagePreloading.maybeCreatePreloadedBrowser(window);
+  isnot(gBrowser.preloadedBrowser, null, "Should have preloaded browser");
+
+  let oldKey = gBrowser.preloadedBrowser.permanentKey;
+
+  let newWin = await openWinWithPreloadBrowser();
+  is(gBrowser.preloadedBrowser, null, "Preloaded browser should be gone");
+  isnot(
+    newWin.gBrowser.preloadedBrowser,
+    null,
+    "Should have moved the preload browser"
+  );
+  is(
+    newWin.gBrowser.preloadedBrowser.permanentKey,
+    oldKey,
+    "Should have the same permanent key"
+  );
+  let browser = newWin.gBrowser.preloadedBrowser;
+  let tab = BrowserTestUtils.addTab(
+    newWin.gBrowser,
+    newWin.BROWSER_NEW_TAB_URL
+  );
+  is(
+    tab.linkedBrowser,
+    browser,
+    "Preloaded browser is usable when opening a new tab."
+  );
+  await promiseNewTabLoadedInBrowser(browser);
+  ok(true, "Successfully loaded the tab.");
+
+  tab = browser = null;
+  await BrowserTestUtils.closeWindow(newWin);
+
+  tab = BrowserTestUtils.addTab(gBrowser, BROWSER_NEW_TAB_URL);
+  await promiseNewTabLoadedInBrowser(tab.linkedBrowser);
+
+  ok(true, "Managed to open a tab in the original window still.");
+
+  BrowserTestUtils.removeTab(tab);
+});
+
+add_task(async function moving_shouldnt_move_across_private_state() {
+  NewTabPagePreloading.MAX_COUNT = 1;
+
+  NewTabPagePreloading.removePreloadedBrowser(window);
+
+  NewTabPagePreloading.maybeCreatePreloadedBrowser(window);
+  isnot(gBrowser.preloadedBrowser, null, "Should have preloaded browser");
+
+  let oldKey = gBrowser.preloadedBrowser.permanentKey;
+  let newWin = await openWinWithPreloadBrowser({ private: true });
+
+  isnot(
+    gBrowser.preloadedBrowser,
+    null,
+    "Preloaded browser in original window should persist"
+  );
+  isnot(
+    newWin.gBrowser.preloadedBrowser,
+    null,
+    "Should have created another preload browser"
+  );
+  isnot(
+    newWin.gBrowser.preloadedBrowser.permanentKey,
+    oldKey,
+    "Should not have the same permanent key"
+  );
+  let browser = newWin.gBrowser.preloadedBrowser;
+  let tab = BrowserTestUtils.addTab(
+    newWin.gBrowser,
+    newWin.BROWSER_NEW_TAB_URL
+  );
+  is(
+    tab.linkedBrowser,
+    browser,
+    "Preloaded browser is usable when opening a new tab."
+  );
+  await promiseNewTabLoadedInBrowser(browser);
+  ok(true, "Successfully loaded the tab.");
+
+  tab = browser = null;
+  await BrowserTestUtils.closeWindow(newWin);
+});
diff --git a/browser/modules/test/browser/browser_taskbar_preview.js b/browser/modules/test/browser/browser_taskbar_preview.js
new file mode 100644
index 0000000000..921a9eb1bc
--- /dev/null
+++ b/browser/modules/test/browser/browser_taskbar_preview.js
@@ -0,0 +1,129 @@
+function test() {
+  var isWin7OrHigher = false;
+  try {
+    let version = Services.sysinfo.getProperty("version");
+    isWin7OrHigher = parseFloat(version) >= 6.1;
+  } catch (ex) {}
+
+  is(
+    !!Win7Features,
+    isWin7OrHigher,
+    "Win7Features available when it should be"
+  );
+  if (!isWin7OrHigher) {
+    return;
+  }
+
+  const ENABLE_PREF_NAME = "browser.taskbar.previews.enable";
+
+  let { AeroPeek } = ChromeUtils.importESModule(
+    "resource:///modules/WindowsPreviewPerTab.sys.mjs"
+  );
+
+  waitForExplicitFinish();
+
+  Services.prefs.setBoolPref(ENABLE_PREF_NAME, true);
+
+  is(1, AeroPeek.windows.length, "Got the expected number of windows");
+
+  checkPreviews(1, "Browser starts with one preview");
+
+  BrowserTestUtils.addTab(gBrowser);
+  BrowserTestUtils.addTab(gBrowser);
+  BrowserTestUtils.addTab(gBrowser);
+
+  checkPreviews(4, "Correct number of previews after adding");
+
+  for (let preview of AeroPeek.previews) {
+    ok(preview.visible, "Preview is shown as expected");
+  }
+
+  Services.prefs.setBoolPref(ENABLE_PREF_NAME, false);
+  is(0, AeroPeek.previews.length, "Should have 0 previews when disabled");
+
+  Services.prefs.setBoolPref(ENABLE_PREF_NAME, true);
+  checkPreviews(4, "Previews are back when re-enabling");
+  for (let preview of AeroPeek.previews) {
+    ok(preview.visible, "Preview is shown as expected after re-enabling");
+  }
+
+  [1, 2, 3, 4].forEach(function (idx) {
+    gBrowser.selectedTab = gBrowser.tabs[idx];
+    ok(checkSelectedTab(), "Current tab is correctly selected");
+  });
+
+  // Close #4
+  getPreviewForTab(gBrowser.selectedTab).controller.onClose();
+  checkPreviews(
+    3,
+    "Expected number of previews after closing selected tab via controller"
+  );
+  Assert.equal(gBrowser.tabs.length, 3, "Successfully closed a tab");
+
+  // Select #1
+  ok(
+    getPreviewForTab(gBrowser.tabs[0]).controller.onActivate(),
+    "Activation was accepted"
+  );
+  ok(gBrowser.tabs[0].selected, "Correct tab was selected");
+  checkSelectedTab();
+
+  // Remove #3 (non active)
+  gBrowser.removeTab(gBrowser.tabs[gBrowser.tabs.length - 1]);
+  checkPreviews(
+    2,
+    "Expected number of previews after closing unselected via browser"
+  );
+
+  // Remove #1 (active)
+  gBrowser.removeTab(gBrowser.tabs[0]);
+  checkPreviews(
+    1,
+    "Expected number of previews after closing selected tab via browser"
+  );
+
+  // Add a new tab
+  BrowserTestUtils.addTab(gBrowser);
+  checkPreviews(2);
+  // Check default selection
+  checkSelectedTab();
+
+  // Change selection
+  gBrowser.selectedTab = gBrowser.tabs[0];
+  checkSelectedTab();
+  // Close nonselected tab via controller
+  getPreviewForTab(gBrowser.tabs[1]).controller.onClose();
+  checkPreviews(1);
+
+  if (Services.prefs.prefHasUserValue(ENABLE_PREF_NAME)) {
+    Services.prefs.setBoolPref(
+      ENABLE_PREF_NAME,
+      !Services.prefs.getBoolPref(ENABLE_PREF_NAME)
+    );
+  }
+
+  finish();
+
+  function checkPreviews(aPreviews, msg) {
+    let nPreviews = AeroPeek.previews.length;
+    is(
+      aPreviews,
+      gBrowser.tabs.length,
+      "Browser has expected number of tabs - " + msg
+    );
+    is(
+      nPreviews,
+      gBrowser.tabs.length,
+      "Browser has one preview per tab - " + msg
+    );
+    is(nPreviews, aPreviews, msg || "Got expected number of previews");
+  }
+
+  function getPreviewForTab(tab) {
+    return window.gTaskbarTabGroup.previewFromTab(tab);
+  }
+
+  function checkSelectedTab() {
+    return getPreviewForTab(gBrowser.selectedTab).active;
+  }
+}
diff --git a/browser/modules/test/browser/browser_urlBar_zoom.js b/browser/modules/test/browser/browser_urlBar_zoom.js
new file mode 100644
index 0000000000..21d8202a52
--- /dev/null
+++ b/browser/modules/test/browser/browser_urlBar_zoom.js
@@ -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";
+
+var initialPageZoom = ZoomManager.zoom;
+const kTimeoutInMS = 20000;
+
+async function testZoomButtonAppearsAndDisappearsBasedOnZoomChanges(
+  zoomEventType
+) {
+  let tab = await BrowserTestUtils.openNewForegroundTab({
+    gBrowser,
+    opening: "https://example.com/",
+    waitForStateStop: true,
+  });
+
+  info("Running this test with " + zoomEventType.substring(0, 9));
+  info("Confirm whether the browser zoom is set to the default level");
+  is(initialPageZoom, 1, "Page zoom is set to default (100%)");
+  let zoomResetButton = document.getElementById("urlbar-zoom-button");
+  is(zoomResetButton.hidden, true, "Zoom reset button is currently hidden");
+
+  info("Change zoom and confirm zoom button appears");
+  let labelUpdatePromise = BrowserTestUtils.waitForAttribute(
+    "label",
+    zoomResetButton
+  );
+  FullZoom.enlarge();
+  await labelUpdatePromise;
+  info("Zoom increased to " + Math.floor(ZoomManager.zoom * 100) + "%");
+  is(zoomResetButton.hidden, false, "Zoom reset button is now visible");
+  let pageZoomLevel = Math.floor(ZoomManager.zoom * 100);
+  let expectedZoomLevel = 110;
+  let buttonZoomLevel = parseInt(zoomResetButton.getAttribute("label"), 10);
+  is(
+    buttonZoomLevel,
+    expectedZoomLevel,
+    "Button label updated successfully to " +
+      Math.floor(ZoomManager.zoom * 100) +
+      "%"
+  );
+
+  let zoomResetPromise = BrowserTestUtils.waitForEvent(window, zoomEventType);
+  zoomResetButton.click();
+  await zoomResetPromise;
+  pageZoomLevel = Math.floor(ZoomManager.zoom * 100);
+  expectedZoomLevel = 100;
+  is(
+    pageZoomLevel,
+    expectedZoomLevel,
+    "Clicking zoom button successfully resets browser zoom to 100%"
+  );
+  is(zoomResetButton.hidden, true, "Zoom reset button returns to being hidden");
+
+  BrowserTestUtils.removeTab(tab);
+}
+
+add_task(async function () {
+  await testZoomButtonAppearsAndDisappearsBasedOnZoomChanges("FullZoomChange");
+  await SpecialPowers.pushPrefEnv({ set: [["browser.zoom.full", false]] });
+  await testZoomButtonAppearsAndDisappearsBasedOnZoomChanges("TextZoomChange");
+  await SpecialPowers.pushPrefEnv({ set: [["browser.zoom.full", true]] });
+});
+
+add_task(async function () {
+  info(
+    "Confirm that URL bar zoom button doesn't appear when customizable zoom widget is added to toolbar"
+  );
+  CustomizableUI.addWidgetToArea("zoom-controls", CustomizableUI.AREA_NAVBAR);
+  let zoomCustomizableWidget = document.getElementById("zoom-reset-button");
+  let zoomResetButton = document.getElementById("urlbar-zoom-button");
+  let zoomChangePromise = BrowserTestUtils.waitForEvent(
+    window,
+    "FullZoomChange"
+  );
+  FullZoom.enlarge();
+  await zoomChangePromise;
+  is(
+    zoomResetButton.hidden,
+    true,
+    "URL zoom button remains hidden despite zoom increase"
+  );
+  is(
+    parseInt(zoomCustomizableWidget.label, 10),
+    110,
+    "Customizable zoom widget's label has updated to " +
+      zoomCustomizableWidget.label
+  );
+});
+
+add_task(async function asyncCleanup() {
+  // reset zoom level and customizable widget
+  ZoomManager.zoom = initialPageZoom;
+  is(ZoomManager.zoom, 1, "Zoom level was restored");
+  if (document.getElementById("zoom-controls")) {
+    CustomizableUI.removeWidgetFromArea(
+      "zoom-controls",
+      CustomizableUI.AREA_NAVBAR
+    );
+    ok(
+      !document.getElementById("zoom-controls"),
+      "Customizable zoom widget removed from toolbar"
+    );
+  }
+});
diff --git a/browser/modules/test/browser/contain_iframe.html b/browser/modules/test/browser/contain_iframe.html
new file mode 100644
index 0000000000..8cea71fae4
--- /dev/null
+++ b/browser/modules/test/browser/contain_iframe.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+  </head>
+  <body><iframe src="http://example.com"></iframe></body>
+</html>
diff --git a/browser/modules/test/browser/file_webrtc.html b/browser/modules/test/browser/file_webrtc.html
new file mode 100644
index 0000000000..1c75f7c75b
--- /dev/null
+++ b/browser/modules/test/browser/file_webrtc.html
@@ -0,0 +1,11 @@
+<html>
+<body onload="start()">
+<script>
+let stream;
+async function start()
+{
+  stream = await navigator.mediaDevices.getUserMedia({ audio: true, video: true })
+}
+</script>
+</body>
+</html>
diff --git a/browser/modules/test/browser/formValidation/browser.toml b/browser/modules/test/browser/formValidation/browser.toml
new file mode 100644
index 0000000000..c7106c356b
--- /dev/null
+++ b/browser/modules/test/browser/formValidation/browser.toml
@@ -0,0 +1,13 @@
+[DEFAULT]
+
+["browser_form_validation.js"]
+skip-if = ["true"] # bug 1057615
+
+["browser_validation_iframe.js"]
+skip-if = ["true"] # bug 1057615
+
+["browser_validation_invisible.js"]
+
+["browser_validation_navigation.js"]
+
+["browser_validation_other_popups.js"]
diff --git a/browser/modules/test/browser/formValidation/browser_form_validation.js b/browser/modules/test/browser/formValidation/browser_form_validation.js
new file mode 100644
index 0000000000..6348546c80
--- /dev/null
+++ b/browser/modules/test/browser/formValidation/browser_form_validation.js
@@ -0,0 +1,522 @@
+/**
+ * COPIED FROM browser/base/content/test/general/head.js.
+ * This function should be removed and replaced with BTU withNewTab calls
+ *
+ * Waits for a load (or custom) event to finish in a given tab. If provided
+ * load an uri into the tab.
+ *
+ * @param tab
+ *        The tab to load into.
+ * @param [optional] url
+ *        The url to load, or the current url.
+ * @return {Promise} resolved when the event is handled.
+ * @resolves to the received event
+ * @rejects if a valid load event is not received within a meaningful interval
+ */
+function promiseTabLoadEvent(tab, url) {
+  info("Wait tab event: load");
+
+  function handle(loadedUrl) {
+    if (loadedUrl === "about:blank" || (url && loadedUrl !== url)) {
+      info(`Skipping spurious load event for ${loadedUrl}`);
+      return false;
+    }
+
+    info("Tab event received: load");
+    return true;
+  }
+
+  let loaded = BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, handle);
+
+  if (url) {
+    BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, url);
+  }
+
+  return loaded;
+}
+
+var gInvalidFormPopup =
+  gBrowser.selectedBrowser.browsingContext.currentWindowGlobal
+    .getActor("FormValidation")
+    ._getAndMaybeCreatePanel(document);
+ok(
+  gInvalidFormPopup,
+  "The browser should have a popup to show when a form is invalid"
+);
+
+function isWithinHalfPixel(a, b) {
+  return Math.abs(a - b) <= 0.5;
+}
+
+function checkPopupShow(anchorRect) {
+  ok(
+    gInvalidFormPopup.state == "showing" || gInvalidFormPopup.state == "open",
+    "[Test " + testId + "] The invalid form popup should be shown"
+  );
+  // Just check the vertical position, as the horizontal position of an
+  // arrow panel will be offset.
+  is(
+    isWithinHalfPixel(gInvalidFormPopup.screenY),
+    isWithinHalfPixel(anchorRect.bottom),
+    "popup top"
+  );
+}
+
+function checkPopupHide() {
+  ok(
+    gInvalidFormPopup.state != "showing" && gInvalidFormPopup.state != "open",
+    "[Test " + testId + "] The invalid form popup should not be shown"
+  );
+}
+
+var testId = 0;
+
+function incrementTest() {
+  testId++;
+  info("Starting next part of test");
+}
+
+function getDocHeader() {
+  return "<html><head><meta charset='utf-8'></head><body>" + getEmptyFrame();
+}
+
+function getDocFooter() {
+  return "</body></html>";
+}
+
+function getEmptyFrame() {
+  return (
+    "<iframe style='width:100px; height:30px; margin:3px; border:1px solid lightgray;' " +
+    "name='t' srcdoc=\"<html><head><meta charset='utf-8'></head><body>form target</body></html>\"></iframe>"
+  );
+}
+
+async function openNewTab(uri, background) {
+  let tab = BrowserTestUtils.addTab(gBrowser);
+  let browser = gBrowser.getBrowserForTab(tab);
+  if (!background) {
+    gBrowser.selectedTab = tab;
+  }
+  await promiseTabLoadEvent(tab, "data:text/html," + escape(uri));
+  return browser;
+}
+
+function clickChildElement(browser) {
+  return SpecialPowers.spawn(browser, [], async function () {
+    let element = content.document.getElementById("s");
+    element.click();
+    return {
+      bottom: content.mozInnerScreenY + element.getBoundingClientRect().bottom,
+    };
+  });
+}
+
+async function blurChildElement(browser) {
+  await SpecialPowers.spawn(browser, [], async function () {
+    content.document.getElementById("i").blur();
+  });
+}
+
+async function checkChildFocus(browser, message) {
+  await SpecialPowers.spawn(
+    browser,
+    [[message, testId]],
+    async function (args) {
+      let [msg, id] = args;
+      var focused =
+        content.document.activeElement == content.document.getElementById("i");
+
+      var validMsg = true;
+      if (msg) {
+        validMsg =
+          msg == content.document.getElementById("i").validationMessage;
+      }
+
+      Assert.equal(
+        focused,
+        true,
+        "Test " + id + " First invalid element should be focused"
+      );
+      Assert.equal(
+        validMsg,
+        true,
+        "Test " +
+          id +
+          " The panel should show the message from validationMessage"
+      );
+    }
+  );
+}
+
+/**
+ * In this test, we check that no popup appears if the form is valid.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  await clickChildElement(browser);
+
+  await new Promise((resolve, reject) => {
+    // XXXndeakin This isn't really going to work when the content is another process
+    executeSoon(function () {
+      checkPopupHide();
+      resolve();
+    });
+  });
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that, when an invalid form is submitted,
+ * the invalid element is focused and a popup appears.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input required id='i'><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that, when an invalid form is submitted,
+ * the first invalid element is focused and a popup appears.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input><input id='i' required><input required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that, we hide the popup by interacting with the
+ * invalid element if the element becomes valid.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popuphidden"
+  );
+  EventUtils.sendString("a");
+  await popupHiddenPromise;
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that, we don't hide the popup by interacting with the
+ * invalid element if the element is still invalid.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input type='email' id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  await new Promise((resolve, reject) => {
+    EventUtils.sendString("a");
+    executeSoon(function () {
+      checkPopupShow(anchorRect);
+      resolve();
+    });
+  });
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that we can hide the popup by blurring the invalid
+ * element.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popuphidden"
+  );
+  await blurChildElement(browser);
+  await popupHiddenPromise;
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that we can hide the popup by pressing TAB.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popuphidden"
+  );
+  EventUtils.synthesizeKey("KEY_Tab");
+  await popupHiddenPromise;
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that the popup will hide if we move to another tab.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser1 = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser1);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser1,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popuphidden"
+  );
+
+  let browser2 = await openNewTab("data:text/html,<html></html>");
+  await popupHiddenPromise;
+
+  gBrowser.removeTab(gBrowser.getTabForBrowser(browser1));
+  gBrowser.removeTab(gBrowser.getTabForBrowser(browser2));
+});
+
+/**
+ * In this test, we check that the popup will hide if we navigate to another
+ * page.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popuphidden"
+  );
+  BrowserTestUtils.startLoadingURIString(
+    browser,
+    "data:text/html,<div>hello!</div>"
+  );
+  await BrowserTestUtils.browserLoaded(browser);
+
+  await popupHiddenPromise;
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we check that the message is correctly updated when it changes.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input type='email' required id='i'><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let inputPromise = BrowserTestUtils.waitForContentEvent(browser, "input");
+  EventUtils.sendString("f");
+  await inputPromise;
+
+  // Now, the element suffers from another error, the message should have
+  // been updated.
+  await new Promise((resolve, reject) => {
+    // XXXndeakin This isn't really going to work when the content is another process
+    executeSoon(function () {
+      checkChildFocus(browser, gInvalidFormPopup.firstElementChild.textContent);
+      resolve();
+    });
+  });
+
+  gBrowser.removeCurrentTab();
+});
+
+/**
+ * In this test, we reload the page while the form validation popup is visible. The validation
+ * popup should hide.
+ */
+add_task(async function () {
+  incrementTest();
+  let uri =
+    getDocHeader() +
+    "<form target='t' action='data:text/html,'><input id='i' required><input id='s' type='submit'></form>" +
+    getDocFooter();
+  let browser = await openNewTab(uri);
+
+  let popupShownPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popupshown"
+  );
+  let anchorRect = await clickChildElement(browser);
+  await popupShownPromise;
+
+  checkPopupShow(anchorRect);
+  await checkChildFocus(
+    browser,
+    gInvalidFormPopup.firstElementChild.textContent
+  );
+
+  let popupHiddenPromise = BrowserTestUtils.waitForEvent(
+    gInvalidFormPopup,
+    "popuphidden"
+  );
+  BrowserReloadSkipCache();
+  await popupHiddenPromise;
+
+  gBrowser.removeCurrentTab();
+});
diff --git a/browser/modules/test/browser/formValidation/browser_validation_iframe.js b/browser/modules/test/browser/formValidation/browser_validation_iframe.js
new file mode 100644
index 0000000000..454c972f32
--- /dev/null
+++ b/browser/modules/test/browser/formValidation/browser_validation_iframe.js
@@ -0,0 +1,67 @@
+/**
+ * Make sure that the form validation error message shows even if the form is in an iframe.
+ */
+add_task(async function test_iframe() {
+  let uri =
+    "data:text/html;charset=utf-8," +
+    escape(
+      "<iframe src=\"data:text/html,<iframe name='t'></iframe><form target='t' action='data:text/html,'><input required id='i'><input id='s' type='submit'></form>\" height=\"600\"></iframe>"
+    );
+
+  var gInvalidFormPopup =
+    gBrowser.selectedBrowser.browsingContext.currentWindowGlobal
+      .getActor("FormValidation")
+      ._getAndMaybeCreatePanel(document);
+  ok(
+    gInvalidFormPopup,
+    "The browser should have a popup to show when a form is invalid"
+  );
+
+  await BrowserTestUtils.withNewTab(uri, async function checkTab(browser) {
+    let popupShownPromise = BrowserTestUtils.waitForEvent(
+      gInvalidFormPopup,
+      "popupshown"
+    );
+
+    await SpecialPowers.spawn(browser, [], async function () {
+      content.document
+        .getElementsByTagName("iframe")[0]
+        .contentDocument.getElementById("s")
+        .click();
+    });
+    await popupShownPromise;
+
+    let anchorBottom = await SpecialPowers.spawn(
+      browser,
+      [],
+      async function () {
+        let childdoc =
+          content.document.getElementsByTagName("iframe")[0].contentDocument;
+        Assert.equal(
+          childdoc.activeElement,
+          childdoc.getElementById("i"),
+          "First invalid element should be focused"
+        );
+        return (
+          childdoc.defaultView.mozInnerScreenY +
+          childdoc.getElementById("i").getBoundingClientRect().bottom
+        );
+      }
+    );
+
+    function isWithinHalfPixel(a, b) {
+      return Math.abs(a - b) <= 0.5;
+    }
+
+    is(
+      isWithinHalfPixel(gInvalidFormPopup.screenY),
+      isWithinHalfPixel(anchorBottom),
+      "popup top"
+    );
+
+    ok(
+      gInvalidFormPopup.state == "showing" || gInvalidFormPopup.state == "open",
+      "The invalid form popup should be shown"
+    );
+  });
+});
diff --git a/browser/modules/test/browser/formValidation/browser_validation_invisible.js b/browser/modules/test/browser/formValidation/browser_validation_invisible.js
new file mode 100644
index 0000000000..9383ad773b
--- /dev/null
+++ b/browser/modules/test/browser/formValidation/browser_validation_invisible.js
@@ -0,0 +1,67 @@
+"use strict";
+
+var gInvalidFormPopup =
+  gBrowser.selectedBrowser.browsingContext.currentWindowGlobal
+    .getActor("FormValidation")
+    ._getAndMaybeCreatePanel(document);
+
+function checkPopupHide() {
+  ok(
+    gInvalidFormPopup.state != "showing" && gInvalidFormPopup.state != "open",
+    "[Test " + testId + "] The invalid form popup should not be shown"
+  );
+}
+
+var testId = 0;
+
+function incrementTest() {
+  testId++;
+  info("Starting next part of test");
+}
+
+/**
+ * In this test, we check that no popup appears if the element display is none.
+ */
+add_task(async function test_display_none() {
+  ok(
+    gInvalidFormPopup,
+    "The browser should have a popup to show when a form is invalid"
+  );
+
+  incrementTest();
+  let testPage =
+    "data:text/html;charset=utf-8," +
+    '<form target="t"><input type="url"  placeholder="url" value="http://" style="display: none;"><input id="s" type="button" value="check"></form>';
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, testPage);
+  await BrowserTestUtils.synthesizeMouse(
+    "#s",
+    0,
+    0,
+    {},
+    gBrowser.selectedBrowser
+  );
+
+  checkPopupHide();
+  BrowserTestUtils.removeTab(tab);
+});
+
+/**
+ * In this test, we check that no popup appears if the element visibility is hidden.
+ */
+add_task(async function test_visibility_hidden() {
+  incrementTest();
+  let testPage =
+    "data:text/html;charset=utf-8," +
+    '<form target="t"><input type="url"  placeholder="url" value="http://" style="visibility: hidden;"><input id="s" type="button" value="check"></form>';
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, testPage);
+  await BrowserTestUtils.synthesizeMouse(
+    "#s",
+    0,
+    0,
+    {},
+    gBrowser.selectedBrowser
+  );
+
+  checkPopupHide();
+  BrowserTestUtils.removeTab(tab);
+});
diff --git a/browser/modules/test/browser/formValidation/browser_validation_navigation.js b/browser/modules/test/browser/formValidation/browser_validation_navigation.js
new file mode 100644
index 0000000000..4dd793b983
--- /dev/null
+++ b/browser/modules/test/browser/formValidation/browser_validation_navigation.js
@@ -0,0 +1,49 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Make sure that the form validation message disappears if we navigate
+ * immediately.
+ */
+add_task(async function test_navigate() {
+  var gInvalidFormPopup =
+    gBrowser.selectedBrowser.browsingContext.currentWindowGlobal
+      .getActor("FormValidation")
+      ._getAndMaybeCreatePanel(document);
+  ok(
+    gInvalidFormPopup,
+    "The browser should have a popup to show when a form is invalid"
+  );
+
+  await BrowserTestUtils.withNewTab(
+    "data:text/html,<body contenteditable='true'><button>Click me",
+    async function checkTab(browser) {
+      let promiseExampleLoaded = BrowserTestUtils.waitForNewTab(
+        browser.getTabBrowser(),
+        "https://example.com/",
+        true
+      );
+      await SpecialPowers.spawn(browser, [], () => {
+        let doc = content.document;
+        let input = doc.createElement("select");
+        input.style.opacity = 0;
+        doc.body.append(input);
+        input.setCustomValidity("This message should not show up.");
+        content.eval(
+          `document.querySelector("button").setAttribute("onmousedown", "document.querySelector('select').reportValidity();window.open('https://example.com/');")`
+        );
+      });
+      await BrowserTestUtils.synthesizeMouseAtCenter("button", {}, browser);
+      let otherTab = await promiseExampleLoaded;
+      await BrowserTestUtils.waitForPopupEvent(gInvalidFormPopup, "hidden");
+      is(
+        gInvalidFormPopup.state,
+        "closed",
+        "Invalid form popup should go away."
+      );
+      BrowserTestUtils.removeTab(otherTab);
+    }
+  );
+});
diff --git a/browser/modules/test/browser/formValidation/browser_validation_other_popups.js b/browser/modules/test/browser/formValidation/browser_validation_other_popups.js
new file mode 100644
index 0000000000..320dff0b59
--- /dev/null
+++ b/browser/modules/test/browser/formValidation/browser_validation_other_popups.js
@@ -0,0 +1,123 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+var gInvalidFormPopup =
+  gBrowser.selectedBrowser.browsingContext.currentWindowGlobal
+    .getActor("FormValidation")
+    ._getAndMaybeCreatePanel(document);
+
+add_task(async function test_other_popup_closes() {
+  ok(
+    gInvalidFormPopup,
+    "The browser should have a popup to show when a form is invalid"
+  );
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/nothere",
+    async function checkTab(browser) {
+      let popupShown = BrowserTestUtils.waitForPopupEvent(
+        gInvalidFormPopup,
+        "shown"
+      );
+      await SpecialPowers.spawn(browser, [], () => {
+        let doc = content.document;
+        let input = doc.createElement("input");
+        doc.body.append(input);
+        input.setCustomValidity("This message should be hidden.");
+        content.eval(`document.querySelector('input').reportValidity();`);
+      });
+      let popupHidden = BrowserTestUtils.waitForPopupEvent(
+        gInvalidFormPopup,
+        "hidden"
+      );
+      await popupShown;
+      let notificationPopup = document.getElementById("notification-popup");
+      let notificationShown = BrowserTestUtils.waitForPopupEvent(
+        notificationPopup,
+        "shown"
+      );
+      let notificationHidden = BrowserTestUtils.waitForPopupEvent(
+        notificationPopup,
+        "hidden"
+      );
+      await SpecialPowers.spawn(browser, [], () => {
+        content.navigator.geolocation.getCurrentPosition(function () {});
+      });
+      await notificationShown;
+      // Should already be hidden at this point.
+      is(
+        gInvalidFormPopup.state,
+        "closed",
+        "Form validation popup should have closed"
+      );
+      // Close just in case.
+      if (gInvalidFormPopup.state != "closed") {
+        gInvalidFormPopup.hidePopup();
+      }
+      await popupHidden;
+      notificationPopup.hidePopup();
+      await notificationHidden;
+    }
+  );
+});
+
+add_task(async function test_dont_open_while_other_popup_open() {
+  ok(
+    gInvalidFormPopup,
+    "The browser should have a popup to show when a form is invalid"
+  );
+  await BrowserTestUtils.withNewTab(
+    "https://example.org/nothere",
+    async function checkTab(browser) {
+      let notificationPopup = document.getElementById("notification-popup");
+      let notificationShown = BrowserTestUtils.waitForPopupEvent(
+        notificationPopup,
+        "shown"
+      );
+      await SpecialPowers.spawn(browser, [], () => {
+        content.navigator.geolocation.getCurrentPosition(function () {});
+      });
+      await notificationShown;
+      let popupShown = BrowserTestUtils.waitForPopupEvent(
+        gInvalidFormPopup,
+        "shown"
+      );
+      is(
+        gInvalidFormPopup.state,
+        "closed",
+        "Form validation popup should be closed."
+      );
+      await SpecialPowers.spawn(browser, [], () => {
+        let doc = content.document;
+        let input = doc.createElement("input");
+        doc.body.append(input);
+        input.setCustomValidity("This message should be hidden.");
+        content.eval(`document.querySelector('input').reportValidity();`);
+      });
+      is(
+        gInvalidFormPopup.state,
+        "closed",
+        "Form validation popup should still be closed."
+      );
+      let notificationHidden = BrowserTestUtils.waitForPopupEvent(
+        notificationPopup,
+        "hidden"
+      );
+      notificationPopup
+        .querySelector(".popup-notification-secondary-button")
+        .click();
+      await notificationHidden;
+      await SpecialPowers.spawn(browser, [], () => {
+        content.eval(`document.querySelector('input').reportValidity();`);
+      });
+      await popupShown;
+      let popupHidden = BrowserTestUtils.waitForPopupEvent(
+        gInvalidFormPopup,
+        "hidden"
+      );
+      gInvalidFormPopup.hidePopup();
+      await popupHidden;
+    }
+  );
+});
diff --git a/browser/modules/test/browser/head.js b/browser/modules/test/browser/head.js
new file mode 100644
index 0000000000..f852cdd641
--- /dev/null
+++ b/browser/modules/test/browser/head.js
@@ -0,0 +1,331 @@
+ChromeUtils.defineESModuleGetters(this, {
+  PlacesTestUtils: "resource://testing-common/PlacesTestUtils.sys.mjs",
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+});
+
+const SINGLE_TRY_TIMEOUT = 100;
+const NUMBER_OF_TRIES = 30;
+
+function waitForConditionPromise(
+  condition,
+  timeoutMsg,
+  tryCount = NUMBER_OF_TRIES
+) {
+  return new Promise((resolve, reject) => {
+    let tries = 0;
+    function checkCondition() {
+      if (tries >= tryCount) {
+        reject(timeoutMsg);
+      }
+      var conditionPassed;
+      try {
+        conditionPassed = condition();
+      } catch (e) {
+        return reject(e);
+      }
+      if (conditionPassed) {
+        return resolve();
+      }
+      tries++;
+      setTimeout(checkCondition, SINGLE_TRY_TIMEOUT);
+      return undefined;
+    }
+    setTimeout(checkCondition, SINGLE_TRY_TIMEOUT);
+  });
+}
+
+function waitForCondition(condition, nextTest, errorMsg) {
+  waitForConditionPromise(condition, errorMsg).then(nextTest, reason => {
+    ok(false, reason + (reason.stack ? "\n" + reason.stack : ""));
+  });
+}
+
+/**
+ * An utility function to write some text in the search input box
+ * in a content page.
+ * @param {Object} browser
+ *        The browser that contains the content.
+ * @param {String} text
+ *        The string to write in the search field.
+ * @param {String} fieldName
+ *        The name of the field to write to.
+ */
+let typeInSearchField = async function (browser, text, fieldName) {
+  await SpecialPowers.spawn(
+    browser,
+    [[fieldName, text]],
+    async function ([contentFieldName, contentText]) {
+      // Put the focus on the search box.
+      let searchInput = content.document.getElementById(contentFieldName);
+      searchInput.focus();
+      searchInput.value = contentText;
+    }
+  );
+};
+
+/**
+ * Given a <xul:browser> at some non-internal web page,
+ * return something that resembles an nsIContentPermissionRequest,
+ * using the browsers currently loaded document to get a principal.
+ *
+ * @param browser (<xul:browser>)
+ *        The browser that we'll create a nsIContentPermissionRequest
+ *        for.
+ * @returns A nsIContentPermissionRequest-ish object.
+ */
+function makeMockPermissionRequest(browser) {
+  let type = {
+    options: Cc["@mozilla.org/array;1"].createInstance(Ci.nsIArray),
+    QueryInterface: ChromeUtils.generateQI(["nsIContentPermissionType"]),
+  };
+  let types = Cc["@mozilla.org/array;1"].createInstance(Ci.nsIMutableArray);
+  types.appendElement(type);
+  let principal = browser.contentPrincipal;
+  let result = {
+    types,
+    isHandlingUserInput: false,
+    principal,
+    topLevelPrincipal: principal,
+    requester: null,
+    _cancelled: false,
+    cancel() {
+      this._cancelled = true;
+    },
+    _allowed: false,
+    allow() {
+      this._allowed = true;
+    },
+    getDelegatePrincipal(aType) {
+      return principal;
+    },
+    QueryInterface: ChromeUtils.generateQI(["nsIContentPermissionRequest"]),
+  };
+
+  // In the e10s-case, nsIContentPermissionRequest will have
+  // element defined. window is defined otherwise.
+  if (browser.isRemoteBrowser) {
+    result.element = browser;
+  } else {
+    result.window = browser.contentWindow;
+  }
+
+  return result;
+}
+
+/**
+ * For an opened PopupNotification, clicks on the main action,
+ * and waits for the panel to fully close.
+ *
+ * @return {Promise}
+ *         Resolves once the panel has fired the "popuphidden"
+ *         event.
+ */
+function clickMainAction() {
+  let removePromise = BrowserTestUtils.waitForEvent(
+    PopupNotifications.panel,
+    "popuphidden"
+  );
+  let popupNotification = getPopupNotificationNode();
+  popupNotification.button.click();
+  return removePromise;
+}
+
+/**
+ * For an opened PopupNotification, clicks on the secondary action,
+ * and waits for the panel to fully close.
+ *
+ * @param actionIndex (Number)
+ *        The index of the secondary action to be clicked. The default
+ *        secondary action (the button shown directly in the panel) is
+ *        treated as having index 0.
+ *
+ * @return {Promise}
+ *         Resolves once the panel has fired the "popuphidden"
+ *         event.
+ */
+function clickSecondaryAction(actionIndex) {
+  let removePromise = BrowserTestUtils.waitForEvent(
+    PopupNotifications.panel,
+    "popuphidden"
+  );
+  let popupNotification = getPopupNotificationNode();
+  if (!actionIndex) {
+    popupNotification.secondaryButton.click();
+    return removePromise;
+  }
+
+  return (async function () {
+    // Click the dropmarker arrow and wait for the menu to show up.
+    let dropdownPromise = BrowserTestUtils.waitForEvent(
+      popupNotification.menupopup,
+      "popupshown"
+    );
+    await EventUtils.synthesizeMouseAtCenter(popupNotification.menubutton, {});
+    await dropdownPromise;
+
+    // The menuitems in the dropdown are accessible as direct children of the panel,
+    // because they are injected into a <children> node in the XBL binding.
+    // The target action is the menuitem at index actionIndex - 1, because the first
+    // secondary action (index 0) is the button shown directly in the panel.
+    let actionMenuItem =
+      popupNotification.querySelectorAll("menuitem")[actionIndex - 1];
+    await EventUtils.synthesizeMouseAtCenter(actionMenuItem, {});
+    await removePromise;
+  })();
+}
+
+/**
+ * Makes sure that 1 (and only 1) <xul:popupnotification> is being displayed
+ * by PopupNotification, and then returns that <xul:popupnotification>.
+ *
+ * @return {<xul:popupnotification>}
+ */
+function getPopupNotificationNode() {
+  // PopupNotification is a bit overloaded here, so to be
+  // clear, popupNotifications is a list of <xul:popupnotification>
+  // nodes.
+  let popupNotifications = PopupNotifications.panel.childNodes;
+  Assert.equal(
+    popupNotifications.length,
+    1,
+    "Should be showing a <xul:popupnotification>"
+  );
+  return popupNotifications[0];
+}
+
+/**
+ * Disable non-release page actions (that are tested elsewhere).
+ *
+ * @return void
+ */
+async function disableNonReleaseActions() {
+  if (!["release", "esr"].includes(AppConstants.MOZ_UPDATE_CHANNEL)) {
+    SpecialPowers.Services.prefs.setBoolPref(
+      "extensions.webcompat-reporter.enabled",
+      false
+    );
+  }
+}
+
+function assertActivatedPageActionPanelHidden() {
+  Assert.ok(
+    !document.getElementById(BrowserPageActions._activatedActionPanelID)
+  );
+}
+
+function promiseOpenPageActionPanel() {
+  let dwu = window.windowUtils;
+  return TestUtils.waitForCondition(() => {
+    // Wait for the main page action button to become visible.  It's hidden for
+    // some URIs, so depending on when this is called, it may not yet be quite
+    // visible.  It's up to the caller to make sure it will be visible.
+    info("Waiting for main page action button to have non-0 size");
+    let bounds = dwu.getBoundsWithoutFlushing(
+      BrowserPageActions.mainButtonNode
+    );
+    return bounds.width > 0 && bounds.height > 0;
+  })
+    .then(() => {
+      // Wait for the panel to become open, by clicking the button if necessary.
+      info("Waiting for main page action panel to be open");
+      if (BrowserPageActions.panelNode.state == "open") {
+        return Promise.resolve();
+      }
+      let shownPromise = promisePageActionPanelShown();
+      EventUtils.synthesizeMouseAtCenter(BrowserPageActions.mainButtonNode, {});
+      return shownPromise;
+    })
+    .then(() => {
+      // Wait for items in the panel to become visible.
+      return promisePageActionViewChildrenVisible(
+        BrowserPageActions.mainViewNode
+      );
+    });
+}
+
+function promisePageActionPanelShown() {
+  return promisePanelShown(BrowserPageActions.panelNode);
+}
+
+function promisePageActionPanelHidden() {
+  return promisePanelHidden(BrowserPageActions.panelNode);
+}
+
+function promisePanelShown(panelIDOrNode) {
+  return promisePanelEvent(panelIDOrNode, "popupshown");
+}
+
+function promisePanelHidden(panelIDOrNode) {
+  return promisePanelEvent(panelIDOrNode, "popuphidden");
+}
+
+function promisePanelEvent(panelIDOrNode, eventType) {
+  return new Promise(resolve => {
+    let panel = panelIDOrNode;
+    if (typeof panel == "string") {
+      panel = document.getElementById(panelIDOrNode);
+      if (!panel) {
+        throw new Error(`Panel with ID "${panelIDOrNode}" does not exist.`);
+      }
+    }
+    if (
+      (eventType == "popupshown" && panel.state == "open") ||
+      (eventType == "popuphidden" && panel.state == "closed")
+    ) {
+      executeSoon(resolve);
+      return;
+    }
+    panel.addEventListener(
+      eventType,
+      () => {
+        executeSoon(resolve);
+      },
+      { once: true }
+    );
+  });
+}
+
+function promisePageActionViewShown() {
+  info("promisePageActionViewShown waiting for ViewShown");
+  return BrowserTestUtils.waitForEvent(
+    BrowserPageActions.panelNode,
+    "ViewShown"
+  ).then(async event => {
+    let panelViewNode = event.originalTarget;
+    await promisePageActionViewChildrenVisible(panelViewNode);
+    return panelViewNode;
+  });
+}
+
+async function promisePageActionViewChildrenVisible(panelViewNode) {
+  info(
+    "promisePageActionViewChildrenVisible waiting for a child node to be visible"
+  );
+  await new Promise(requestAnimationFrame);
+  let dwu = window.windowUtils;
+  return TestUtils.waitForCondition(() => {
+    let bodyNode = panelViewNode.firstElementChild;
+    for (let childNode of bodyNode.children) {
+      let bounds = dwu.getBoundsWithoutFlushing(childNode);
+      if (bounds.width > 0 && bounds.height > 0) {
+        return true;
+      }
+    }
+    return false;
+  });
+}
+
+async function initPageActionsTest() {
+  await disableNonReleaseActions();
+
+  // Ensure screenshots is really disabled (bug 1498738)
+  const addon = await AddonManager.getAddonByID("screenshots@mozilla.org");
+  await addon.disable({ allowSystemAddons: true });
+
+  // Make the main button visible. It's not unless the window is narrow. This
+  // test isn't concerned with that behavior. We have other tests for that.
+  BrowserPageActions.mainButtonNode.style.visibility = "visible";
+  registerCleanupFunction(() => {
+    BrowserPageActions.mainButtonNode.style.removeProperty("visibility");
+  });
+}
diff --git a/browser/modules/test/unit/test_E10SUtils_nested_URIs.js b/browser/modules/test/unit/test_E10SUtils_nested_URIs.js
new file mode 100644
index 0000000000..5ebcac114f
--- /dev/null
+++ b/browser/modules/test/unit/test_E10SUtils_nested_URIs.js
@@ -0,0 +1,90 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+
+const { E10SUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/E10SUtils.sys.mjs"
+);
+
+var TEST_PREFERRED_REMOTE_TYPES = [
+  E10SUtils.WEB_REMOTE_TYPE,
+  E10SUtils.NOT_REMOTE,
+  "fakeRemoteType",
+];
+
+// These test cases give a nestedURL and a plainURL that should always load in
+// the same remote type. By making these tests comparisons, they should work
+// with any pref combination.
+var TEST_CASES = [
+  {
+    nestedURL: "jar:file:///some.file!/",
+    plainURL: "file:///some.file",
+  },
+  {
+    nestedURL: "jar:jar:file:///some.file!/!/",
+    plainURL: "file:///some.file",
+  },
+  {
+    nestedURL: "jar:http://some.site/file!/",
+    plainURL: "http://some.site/file",
+  },
+  {
+    nestedURL: "view-source:http://some.site",
+    plainURL: "http://some.site",
+  },
+  {
+    nestedURL: "view-source:file:///some.file",
+    plainURL: "file:///some.file",
+  },
+  {
+    nestedURL: "view-source:about:home",
+    plainURL: "about:home",
+  },
+  {
+    nestedURL: "view-source:about:robots",
+    plainURL: "about:robots",
+  },
+  {
+    nestedURL: "view-source:pcast:http://some.site",
+    plainURL: "http://some.site",
+  },
+];
+
+function run_test() {
+  for (let testCase of TEST_CASES) {
+    for (let preferredRemoteType of TEST_PREFERRED_REMOTE_TYPES) {
+      let plainUri = Services.io.newURI(testCase.plainURL);
+      let plainRemoteType = E10SUtils.getRemoteTypeForURIObject(plainUri, {
+        multiProcess: true,
+        remoteSubFrames: false,
+        preferredRemoteType,
+      });
+
+      let nestedUri = Services.io.newURI(testCase.nestedURL);
+      let nestedRemoteType = E10SUtils.getRemoteTypeForURIObject(nestedUri, {
+        multiProcess: true,
+        remoteSubFrames: false,
+        preferredRemoteType,
+      });
+
+      let nestedStr = nestedUri.scheme + ":";
+      do {
+        nestedUri = nestedUri.QueryInterface(Ci.nsINestedURI).innerURI;
+        if (nestedUri.scheme == "about") {
+          nestedStr += nestedUri.spec;
+          break;
+        }
+
+        nestedStr += nestedUri.scheme + ":";
+      } while (nestedUri instanceof Ci.nsINestedURI);
+
+      let plainStr =
+        plainUri.scheme == "about" ? plainUri.spec : plainUri.scheme + ":";
+      equal(
+        nestedRemoteType,
+        plainRemoteType,
+        `Check that ${nestedStr} loads in same remote type as ${plainStr}` +
+          ` with preferred remote type: ${preferredRemoteType}`
+      );
+    }
+  }
+}
diff --git a/browser/modules/test/unit/test_HomePage.js b/browser/modules/test/unit/test_HomePage.js
new file mode 100644
index 0000000000..f2f4588329
--- /dev/null
+++ b/browser/modules/test/unit/test_HomePage.js
@@ -0,0 +1,85 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  HomePage: "resource:///modules/HomePage.sys.mjs",
+  RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+const HOMEPAGE_IGNORELIST = "homepage-urls";
+
+/**
+ * Provides a basic set of remote settings for use in tests.
+ */
+async function setupRemoteSettings() {
+  const settings = await RemoteSettings("hijack-blocklists");
+  sinon.stub(settings, "get").returns([
+    {
+      id: HOMEPAGE_IGNORELIST,
+      matches: ["ignore=me"],
+      _status: "synced",
+    },
+  ]);
+}
+
+add_task(async function setup() {
+  await setupRemoteSettings();
+});
+
+add_task(function test_HomePage() {
+  Assert.ok(
+    !HomePage.overridden,
+    "Homepage should not be overriden by default."
+  );
+  let newvalue = "about:blank|about:newtab";
+  HomePage.safeSet(newvalue);
+  Assert.ok(HomePage.overridden, "Homepage should be overriden after set()");
+  Assert.equal(HomePage.get(), newvalue, "Homepage should be ${newvalue}");
+  Assert.notEqual(
+    HomePage.getDefault(),
+    newvalue,
+    "Homepage should be ${newvalue}"
+  );
+  HomePage.reset();
+  Assert.ok(
+    !HomePage.overridden,
+    "Homepage should not be overriden by after reset."
+  );
+  Assert.equal(
+    HomePage.get(),
+    HomePage.getDefault(),
+    "Homepage and default should be equal after reset."
+  );
+});
+
+add_task(function test_readLocalizedHomepage() {
+  let newvalue = "data:text/plain,browser.startup.homepage%3Dabout%3Alocalized";
+  let complexvalue = Cc["@mozilla.org/pref-localizedstring;1"].createInstance(
+    Ci.nsIPrefLocalizedString
+  );
+  complexvalue.data = newvalue;
+  Services.prefs
+    .getDefaultBranch(null)
+    .setComplexValue(
+      "browser.startup.homepage",
+      Ci.nsIPrefLocalizedString,
+      complexvalue
+    );
+  Assert.ok(!HomePage.overridden, "Complex value only works as default");
+  Assert.equal(HomePage.get(), "about:localized", "Get value from bundle");
+});
+
+add_task(function test_recoverEmptyHomepage() {
+  Assert.ok(
+    !HomePage.overridden,
+    "Homepage should not be overriden by default."
+  );
+  Services.prefs.setStringPref("browser.startup.homepage", "");
+  Assert.ok(HomePage.overridden, "Homepage is overriden with empty string.");
+  Assert.equal(HomePage.get(), HomePage.getDefault(), "Recover is default");
+  Assert.ok(!HomePage.overridden, "Recover should have set default");
+});
diff --git a/browser/modules/test/unit/test_HomePage_ignore.js b/browser/modules/test/unit/test_HomePage_ignore.js
new file mode 100644
index 0000000000..1369b661b6
--- /dev/null
+++ b/browser/modules/test/unit/test_HomePage_ignore.js
@@ -0,0 +1,128 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  HomePage: "resource:///modules/HomePage.sys.mjs",
+  RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+const HOMEPAGE_IGNORELIST = "homepage-urls";
+
+/**
+ * Provides a basic set of remote settings for use in tests.
+ */
+async function setupRemoteSettings() {
+  const settings = await RemoteSettings("hijack-blocklists");
+  sinon.stub(settings, "get").returns([
+    {
+      id: HOMEPAGE_IGNORELIST,
+      matches: ["ignore=me", "ignoreCASE=ME"],
+      _status: "synced",
+    },
+  ]);
+}
+
+add_task(async function setup() {
+  await setupRemoteSettings();
+});
+
+add_task(async function test_initWithIgnoredPageCausesReset() {
+  // Set the preference direct as the set() would block us.
+  Services.prefs.setStringPref(
+    "browser.startup.homepage",
+    "http://bad/?ignore=me"
+  );
+  Assert.ok(HomePage.overridden, "Should have overriden the homepage");
+
+  await HomePage.delayedStartup();
+
+  Assert.ok(
+    !HomePage.overridden,
+    "Should no longer be overriding the homepage."
+  );
+  Assert.equal(
+    HomePage.get(),
+    HomePage.getDefault(),
+    "Should have reset to the default preference"
+  );
+
+  TelemetryTestUtils.assertEvents(
+    [{ object: "ignore", value: "saved_reset" }],
+    {
+      category: "homepage",
+      method: "preference",
+    }
+  );
+});
+
+add_task(async function test_updateIgnoreListCausesReset() {
+  Services.prefs.setStringPref(
+    "browser.startup.homepage",
+    "http://bad/?new=ignore"
+  );
+  Assert.ok(HomePage.overridden, "Should have overriden the homepage");
+
+  // Simulate an ignore list update.
+  await RemoteSettings("hijack-blocklists").emit("sync", {
+    data: {
+      current: [
+        {
+          id: HOMEPAGE_IGNORELIST,
+          schema: 1553857697843,
+          last_modified: 1553859483588,
+          matches: ["ignore=me", "ignoreCASE=ME", "new=ignore"],
+        },
+      ],
+    },
+  });
+
+  Assert.ok(
+    !HomePage.overridden,
+    "Should no longer be overriding the homepage."
+  );
+  Assert.equal(
+    HomePage.get(),
+    HomePage.getDefault(),
+    "Should have reset to the default preference"
+  );
+  TelemetryTestUtils.assertEvents(
+    [{ object: "ignore", value: "saved_reset" }],
+    {
+      category: "homepage",
+      method: "preference",
+    }
+  );
+});
+
+async function testSetIgnoredUrl(url) {
+  Assert.ok(!HomePage.overriden, "Should not be overriding the homepage");
+
+  await HomePage.set(url);
+
+  Assert.equal(
+    HomePage.get(),
+    HomePage.getDefault(),
+    "Should still have the default homepage."
+  );
+  Assert.ok(!HomePage.overriden, "Should not be overriding the homepage.");
+  TelemetryTestUtils.assertEvents(
+    [{ object: "ignore", value: "set_blocked" }],
+    {
+      category: "homepage",
+      method: "preference",
+    }
+  );
+}
+
+add_task(async function test_setIgnoredUrl() {
+  await testSetIgnoredUrl("http://bad/?ignore=me");
+});
+
+add_task(async function test_setIgnoredUrl_case() {
+  await testSetIgnoredUrl("http://bad/?Ignorecase=me");
+});
diff --git a/browser/modules/test/unit/test_InstallationTelemetry.js b/browser/modules/test/unit/test_InstallationTelemetry.js
new file mode 100644
index 0000000000..4bb9acbd75
--- /dev/null
+++ b/browser/modules/test/unit/test_InstallationTelemetry.js
@@ -0,0 +1,234 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+const { BrowserUsageTelemetry } = ChromeUtils.importESModule(
+  "resource:///modules/BrowserUsageTelemetry.sys.mjs"
+);
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+ChromeUtils.defineESModuleGetters(this, {
+  FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
+});
+
+const TIMESTAMP_PREF = "app.installation.timestamp";
+
+function encodeUtf16(str) {
+  const buf = new ArrayBuffer(str.length * 2);
+  const utf16 = new Uint16Array(buf);
+  for (let i = 0; i < str.length; i++) {
+    utf16[i] = str.charCodeAt(i);
+  }
+  return new Uint8Array(buf);
+}
+
+// Returns Promise
+function writeJsonUtf16(fileName, obj) {
+  const str = JSON.stringify(obj);
+  return IOUtils.write(fileName, encodeUtf16(str));
+}
+
+async function runReport(
+  dataFile,
+  installType,
+  { clearTS, setTS, assertRejects, expectExtra, expectTS, msixPrefixes }
+) {
+  // Setup timestamp
+  if (clearTS) {
+    Services.prefs.clearUserPref(TIMESTAMP_PREF);
+  }
+  if (typeof setTS == "string") {
+    Services.prefs.setStringPref(TIMESTAMP_PREF, setTS);
+  }
+
+  // Init events
+  Services.telemetry.clearEvents();
+
+  // Exercise reportInstallationTelemetry
+  if (typeof assertRejects != "undefined") {
+    await Assert.rejects(
+      BrowserUsageTelemetry.reportInstallationTelemetry(dataFile),
+      assertRejects
+    );
+  } else if (!msixPrefixes) {
+    await BrowserUsageTelemetry.reportInstallationTelemetry(dataFile);
+  } else {
+    await BrowserUsageTelemetry.reportInstallationTelemetry(
+      dataFile,
+      msixPrefixes
+    );
+  }
+
+  // Check events
+  TelemetryTestUtils.assertEvents(
+    expectExtra
+      ? [{ object: installType, value: null, extra: expectExtra }]
+      : [],
+    { category: "installation", method: "first_seen" }
+  );
+
+  // Check timestamp
+  if (typeof expectTS == "string") {
+    Assert.equal(expectTS, Services.prefs.getStringPref(TIMESTAMP_PREF));
+  }
+}
+
+let condition = {
+  skip_if: () =>
+    AppConstants.platform !== "win" ||
+    !Services.sysinfo.getProperty("hasWinPackageId"),
+};
+add_task(condition, async function testInstallationTelemetryMSIX() {
+  // Unfortunately, we have no way to inject different installation ping data
+  // into the system in a way that doesn't just completely override the code
+  // under test - so other than a basic test of the happy path, there's
+  // nothing we can do here.
+  let msixExtra = {
+    version: AppConstants.MOZ_APP_VERSION,
+    build_id: AppConstants.MOZ_BULIDID,
+    admin_user: "false",
+    from_msi: "false",
+    silent: "false",
+    default_path: "true",
+    install_existed: "false",
+    other_inst: "false",
+    other_msix_inst: "false",
+    profdir_existed: "false",
+  };
+
+  await runReport("fake", "msix", {
+    expectExtra: msixExtra,
+  });
+});
+condition = {
+  skip_if: () =>
+    AppConstants.platform === "win" &&
+    Services.sysinfo.getProperty("hasWinPackageId"),
+};
+add_task(condition, async function testInstallationTelemetry() {
+  let dataFilePath = await IOUtils.createUniqueFile(
+    Services.dirsvc.get("TmpD", Ci.nsIFile).path,
+    "installation-telemetry-test-data" + Math.random() + ".json"
+  );
+  let dataFile = new FileUtils.File(dataFilePath);
+
+  registerCleanupFunction(async () => {
+    try {
+      await IOUtils.remove(dataFilePath);
+    } catch (ex) {
+      // Ignore remove failure, file may not exist by now
+    }
+
+    Services.prefs.clearUserPref(TIMESTAMP_PREF);
+  });
+
+  // Test with normal stub data
+  let stubData = {
+    version: "99.0abc",
+    build_id: "123",
+    installer_type: "stub",
+    admin_user: true,
+    install_existed: false,
+    profdir_existed: false,
+    install_timestamp: "0",
+  };
+  let stubExtra = {
+    version: "99.0abc",
+    build_id: "123",
+    admin_user: "true",
+    install_existed: "false",
+    other_inst: "false",
+    other_msix_inst: "false",
+    profdir_existed: "false",
+  };
+
+  await writeJsonUtf16(dataFilePath, stubData);
+  await runReport(dataFile, "stub", {
+    clearTS: true,
+    expectExtra: stubExtra,
+    expectTS: "0",
+  });
+
+  // Check that it doesn't generate another event when the timestamp is unchanged
+  await runReport(dataFile, "stub", { expectTS: "0" });
+
+  // New timestamp
+  stubData.install_timestamp = "1";
+  await writeJsonUtf16(dataFilePath, stubData);
+  await runReport(dataFile, "stub", {
+    expectExtra: stubExtra,
+    expectTS: "1",
+  });
+
+  // Test with normal full data
+  let fullData = {
+    version: "99.0abc",
+    build_id: "123",
+    installer_type: "full",
+    admin_user: false,
+    install_existed: true,
+    profdir_existed: true,
+    silent: false,
+    from_msi: false,
+    default_path: true,
+
+    install_timestamp: "1",
+  };
+  let fullExtra = {
+    version: "99.0abc",
+    build_id: "123",
+    admin_user: "false",
+    install_existed: "true",
+    other_inst: "false",
+    other_msix_inst: "false",
+    profdir_existed: "true",
+    silent: "false",
+    from_msi: "false",
+    default_path: "true",
+  };
+
+  await writeJsonUtf16(dataFilePath, fullData);
+  await runReport(dataFile, "full", {
+    clearTS: true,
+    expectExtra: fullExtra,
+    expectTS: "1",
+  });
+
+  // Check that it doesn't generate another event when the timestamp is unchanged
+  await runReport(dataFile, "full", { expectTS: "1" });
+
+  // New timestamp and a check to make sure we can find installed MSIX packages
+  // by overriding the prefixes a bit further down.
+  fullData.install_timestamp = "2";
+  // This check only works on Windows
+  if (AppConstants.platform == "win") {
+    fullExtra.other_msix_inst = "true";
+  }
+  await writeJsonUtf16(dataFilePath, fullData);
+  await runReport(dataFile, "full", {
+    expectExtra: fullExtra,
+    expectTS: "2",
+    msixPrefixes: ["Microsoft"],
+  });
+
+  // Missing field
+  delete fullData.install_existed;
+  fullData.install_timestamp = "3";
+  await writeJsonUtf16(dataFilePath, fullData);
+  await runReport(dataFile, "full", { assertRejects: /install_existed/ });
+
+  // Malformed JSON
+  await IOUtils.write(dataFilePath, encodeUtf16("hello"));
+  await runReport(dataFile, "stub", {
+    assertRejects: /unexpected character/,
+  });
+
+  // Missing file, should return with no exception
+  await IOUtils.remove(dataFilePath);
+  await runReport(dataFile, "stub", { setTS: "3", expectTS: "3" });
+});
diff --git a/browser/modules/test/unit/test_LaterRun.js b/browser/modules/test/unit/test_LaterRun.js
new file mode 100644
index 0000000000..6de572b868
--- /dev/null
+++ b/browser/modules/test/unit/test_LaterRun.js
@@ -0,0 +1,244 @@
+"use strict";
+
+const kEnabledPref = "browser.laterrun.enabled";
+const kPagePrefRoot = "browser.laterrun.pages.";
+const kSessionCountPref = "browser.laterrun.bookkeeping.sessionCount";
+const kProfileCreationTime = "browser.laterrun.bookkeeping.profileCreationTime";
+
+const { LaterRun } = ChromeUtils.importESModule(
+  "resource:///modules/LaterRun.sys.mjs"
+);
+
+Services.prefs.setBoolPref(kEnabledPref, true);
+const { updateAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+updateAppInfo();
+
+add_task(async function test_page_applies() {
+  Services.prefs.setCharPref(
+    kPagePrefRoot + "test_LaterRun_unittest.url",
+    "https://www.mozilla.org/%VENDOR%/%NAME%/%ID%/%VERSION%/"
+  );
+  Services.prefs.setIntPref(
+    kPagePrefRoot + "test_LaterRun_unittest.minimumHoursSinceInstall",
+    10
+  );
+  Services.prefs.setIntPref(
+    kPagePrefRoot + "test_LaterRun_unittest.minimumSessionCount",
+    3
+  );
+
+  let pages = LaterRun.readPages();
+  // We have to filter the pages because it's possible Firefox ships with other URLs
+  // that get included in this test.
+  pages = pages.filter(
+    page => page.pref == kPagePrefRoot + "test_LaterRun_unittest."
+  );
+  Assert.equal(pages.length, 1, "Got 1 page");
+  let page = pages[0];
+  Assert.equal(
+    page.pref,
+    kPagePrefRoot + "test_LaterRun_unittest.",
+    "Should know its own pref"
+  );
+  Assert.equal(
+    page.minimumHoursSinceInstall,
+    10,
+    "Needs to have 10 hours since install"
+  );
+  Assert.equal(page.minimumSessionCount, 3, "Needs to have 3 sessions");
+  Assert.equal(page.requireBoth, false, "Either requirement is enough");
+  let expectedURL =
+    "https://www.mozilla.org/" +
+    Services.appinfo.vendor +
+    "/" +
+    Services.appinfo.name +
+    "/" +
+    Services.appinfo.ID +
+    "/" +
+    Services.appinfo.version +
+    "/";
+  Assert.equal(page.url, expectedURL, "URL is stored correctly");
+
+  Assert.ok(
+    page.applies({ hoursSinceInstall: 1, sessionCount: 3 }),
+    "Applies when session count has been met."
+  );
+  Assert.ok(
+    page.applies({ hoursSinceInstall: 1, sessionCount: 4 }),
+    "Applies when session count has been exceeded."
+  );
+  Assert.ok(
+    page.applies({ hoursSinceInstall: 10, sessionCount: 2 }),
+    "Applies when total session time has been met."
+  );
+  Assert.ok(
+    page.applies({ hoursSinceInstall: 20, sessionCount: 2 }),
+    "Applies when total session time has been exceeded."
+  );
+  Assert.ok(
+    page.applies({ hoursSinceInstall: 10, sessionCount: 3 }),
+    "Applies when both time and session count have been met."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 1 }),
+    "Does not apply when neither time and session count have been met."
+  );
+
+  page.requireBoth = true;
+
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 3 }),
+    "Does not apply when only session count has been met."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 4 }),
+    "Does not apply when only session count has been exceeded."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 10, sessionCount: 2 }),
+    "Does not apply when only total session time has been met."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 20, sessionCount: 2 }),
+    "Does not apply when only total session time has been exceeded."
+  );
+  Assert.ok(
+    page.applies({ hoursSinceInstall: 10, sessionCount: 3 }),
+    "Applies when both time and session count have been met."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 1 }),
+    "Does not apply when neither time and session count have been met."
+  );
+
+  // Check that pages that have run never apply:
+  Services.prefs.setBoolPref(
+    kPagePrefRoot + "test_LaterRun_unittest.hasRun",
+    true
+  );
+  page.requireBoth = false;
+
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 3 }),
+    "Does not apply when page has already run (sessionCount equal)."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 4 }),
+    "Does not apply when page has already run (sessionCount exceeding)."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 10, sessionCount: 2 }),
+    "Does not apply when page has already run (hoursSinceInstall equal)."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 20, sessionCount: 2 }),
+    "Does not apply when page has already run (hoursSinceInstall exceeding)."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 10, sessionCount: 3 }),
+    "Does not apply when page has already run (both criteria equal)."
+  );
+  Assert.ok(
+    !page.applies({ hoursSinceInstall: 1, sessionCount: 1 }),
+    "Does not apply when page has already run (both criteria insufficient anyway)."
+  );
+
+  clearAllPagePrefs();
+});
+
+add_task(async function test_get_URL() {
+  Services.prefs.setIntPref(
+    kProfileCreationTime,
+    Math.floor((Date.now() - 11 * 60 * 60 * 1000) / 1000)
+  );
+  Services.prefs.setCharPref(
+    kPagePrefRoot + "test_LaterRun_unittest.url",
+    "https://www.mozilla.org/"
+  );
+  Services.prefs.setIntPref(
+    kPagePrefRoot + "test_LaterRun_unittest.minimumHoursSinceInstall",
+    10
+  );
+  Services.prefs.setIntPref(
+    kPagePrefRoot + "test_LaterRun_unittest.minimumSessionCount",
+    3
+  );
+  let pages = LaterRun.readPages();
+  // We have to filter the pages because it's possible Firefox ships with other URLs
+  // that get included in this test.
+  pages = pages.filter(
+    page => page.pref == kPagePrefRoot + "test_LaterRun_unittest."
+  );
+  Assert.equal(pages.length, 1, "Should only be 1 matching page");
+  let page = pages[0];
+  let url;
+  do {
+    url = LaterRun.getURL();
+    // We have to loop because it's possible Firefox ships with other URLs that get triggered by
+    // this test.
+  } while (url && url != "https://www.mozilla.org/");
+  Assert.equal(
+    url,
+    "https://www.mozilla.org/",
+    "URL should be as expected when prefs are set."
+  );
+  Assert.ok(
+    Services.prefs.prefHasUserValue(
+      kPagePrefRoot + "test_LaterRun_unittest.hasRun"
+    ),
+    "Should have set pref"
+  );
+  Assert.ok(
+    Services.prefs.getBoolPref(kPagePrefRoot + "test_LaterRun_unittest.hasRun"),
+    "Should have set pref to true"
+  );
+  Assert.ok(page.hasRun, "Other page objects should know it has run, too.");
+
+  clearAllPagePrefs();
+});
+
+add_task(async function test_insecure_urls() {
+  Services.prefs.setCharPref(
+    kPagePrefRoot + "test_LaterRun_unittest.url",
+    "http://www.mozilla.org/"
+  );
+  Services.prefs.setIntPref(
+    kPagePrefRoot + "test_LaterRun_unittest.minimumHoursSinceInstall",
+    10
+  );
+  Services.prefs.setIntPref(
+    kPagePrefRoot + "test_LaterRun_unittest.minimumSessionCount",
+    3
+  );
+  let pages = LaterRun.readPages();
+  // We have to filter the pages because it's possible Firefox ships with other URLs
+  // that get triggered in this test.
+  pages = pages.filter(
+    page => page.pref == kPagePrefRoot + "test_LaterRun_unittest."
+  );
+  Assert.equal(pages.length, 0, "URL with non-https scheme should get ignored");
+  clearAllPagePrefs();
+});
+
+add_task(async function test_dynamic_pref_getter_setter() {
+  delete LaterRun._sessionCount;
+  Services.prefs.setIntPref(kSessionCountPref, 0);
+  Assert.equal(LaterRun.sessionCount, 0, "Should start at 0");
+
+  LaterRun.sessionCount++;
+  Assert.equal(LaterRun.sessionCount, 1, "Should increment.");
+  Assert.equal(
+    Services.prefs.getIntPref(kSessionCountPref),
+    1,
+    "Should update pref"
+  );
+});
+
+function clearAllPagePrefs() {
+  let allChangedPrefs = Services.prefs.getChildList(kPagePrefRoot);
+  for (let pref of allChangedPrefs) {
+    Services.prefs.clearUserPref(pref);
+  }
+}
diff --git a/browser/modules/test/unit/test_ProfileCounter.js b/browser/modules/test/unit/test_ProfileCounter.js
new file mode 100644
index 0000000000..2a22d849ff
--- /dev/null
+++ b/browser/modules/test/unit/test_ProfileCounter.js
@@ -0,0 +1,239 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { BrowserUsageTelemetry } = ChromeUtils.importESModule(
+  "resource:///modules/BrowserUsageTelemetry.sys.mjs"
+);
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+const PROFILE_COUNT_SCALAR = "browser.engagement.profile_count";
+// Largest possible uint32_t value represents an error.
+const SCALAR_ERROR_VALUE = 0;
+
+const FILE_OPEN_OPERATION = "open";
+const ERROR_FILE_NOT_FOUND = "NotFoundError";
+const ERROR_ACCESS_DENIED = "NotAllowedError";
+
+// We will redirect I/O to/from the profile counter file to read/write this
+// variable instead. That makes it easier for us to:
+//   - avoid interference from any pre-existing file
+//   - read and change the values in the file.
+//   - clean up changes made to the file
+// We will translate a null value stored here to a File Not Found error.
+var gFakeProfileCounterFile = null;
+// We will use this to check that the profile counter code doesn't try to write
+// to multiple files (since this test will malfunction in that case due to
+// gFakeProfileCounterFile only being setup to accommodate a single file).
+var gProfileCounterFilePath = null;
+
+// Storing a value here lets us test the behavior when we encounter an error
+// reading or writing to the file. A null value means that no error will
+// be simulated (other than possibly a NotFoundError).
+var gNextReadExceptionReason = null;
+var gNextWriteExceptionReason = null;
+
+// Nothing will actually be stored in this directory, so it's not important that
+// it be valid, but the leafname should be unique to this test in order to be
+// sure of preventing name conflicts with the pref:
+// `browser.engagement.profileCounted.${hash}`
+function getDummyUpdateDirectory() {
+  const testName = "test_ProfileCounter";
+  let dir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+  dir.initWithPath(`C:\\foo\\bar\\${testName}`);
+  return dir;
+}
+
+// We aren't going to bother generating anything looking like a real client ID
+// for this. The only real requirements for client ids is that they not repeat
+// and that they be strings. So we'll just return an integer as a string and
+// increment it when we want a new client id.
+var gDummyTelemetryClientId = 0;
+function getDummyTelemetryClientId() {
+  return gDummyTelemetryClientId.toString();
+}
+function setNewDummyTelemetryClientId() {
+  ++gDummyTelemetryClientId;
+}
+
+// Returns null if the (fake) profile count file hasn't been created yet.
+function getProfileCount() {
+  // Strict equality to ensure distinguish properly between a non-existent
+  // file and an empty one.
+  if (gFakeProfileCounterFile === null) {
+    return null;
+  }
+  let saveData = JSON.parse(gFakeProfileCounterFile);
+  return saveData.profileTelemetryIds.length;
+}
+
+// Resets the state to the original state, before the profile count file has
+// even been written.
+// If resetFile is specified as false, this will reset everything except for the
+// file itself. This allows us to sort of pretend that another installation
+// wrote the file.
+function reset(resetFile = true) {
+  if (resetFile) {
+    gFakeProfileCounterFile = null;
+  }
+  gNextReadExceptionReason = null;
+  gNextWriteExceptionReason = null;
+  setNewDummyTelemetryClientId();
+}
+
+function setup() {
+  reset();
+  // FOG needs a profile directory to put its data in.
+  do_get_profile();
+  // Initialize FOG so we can test the FOG version of profile count
+  Services.fog.initializeFOG();
+  Services.fog.testResetFOG();
+
+  BrowserUsageTelemetry.Policy.readProfileCountFile = async path => {
+    if (!gProfileCounterFilePath) {
+      gProfileCounterFilePath = path;
+    } else {
+      // We've only got one mock-file variable. Make sure we are always
+      // accessing the same file or this will cause problems.
+      Assert.equal(
+        gProfileCounterFilePath,
+        path,
+        "Only one file should be accessed"
+      );
+    }
+    // Strict equality to ensure distinguish properly between null and 0.
+    if (gNextReadExceptionReason !== null) {
+      let ex = new DOMException(FILE_OPEN_OPERATION, gNextReadExceptionReason);
+      gNextReadExceptionReason = null;
+      throw ex;
+    }
+    // Strict equality to ensure distinguish properly between a non-existent
+    // file and an empty one.
+    if (gFakeProfileCounterFile === null) {
+      throw new DOMException(FILE_OPEN_OPERATION, ERROR_FILE_NOT_FOUND);
+    }
+    return gFakeProfileCounterFile;
+  };
+  BrowserUsageTelemetry.Policy.writeProfileCountFile = async (path, data) => {
+    if (!gProfileCounterFilePath) {
+      gProfileCounterFilePath = path;
+    } else {
+      // We've only got one mock-file variable. Make sure we are always
+      // accessing the same file or this will cause problems.
+      Assert.equal(
+        gProfileCounterFilePath,
+        path,
+        "Only one file should be accessed"
+      );
+    }
+    // Strict equality to ensure distinguish properly between null and 0.
+    if (gNextWriteExceptionReason !== null) {
+      let ex = new DOMException(FILE_OPEN_OPERATION, gNextWriteExceptionReason);
+      gNextWriteExceptionReason = null;
+      throw ex;
+    }
+    gFakeProfileCounterFile = data;
+  };
+  BrowserUsageTelemetry.Policy.getUpdateDirectory = getDummyUpdateDirectory;
+  BrowserUsageTelemetry.Policy.getTelemetryClientId = getDummyTelemetryClientId;
+}
+
+// Checks that the number of profiles reported is the number expected. Because
+// of bucketing, the raw count may be different than the reported count.
+function checkSuccess(profilesReported, rawCount = profilesReported) {
+  Assert.equal(rawCount, getProfileCount());
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+  TelemetryTestUtils.assertScalar(
+    scalars,
+    PROFILE_COUNT_SCALAR,
+    profilesReported,
+    "The value reported to telemetry should be the expected profile count"
+  );
+  Assert.equal(
+    profilesReported,
+    Glean.browserEngagement.profileCount.testGetValue()
+  );
+}
+
+function checkError() {
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+  TelemetryTestUtils.assertScalar(
+    scalars,
+    PROFILE_COUNT_SCALAR,
+    SCALAR_ERROR_VALUE,
+    "The value reported to telemetry should be the error value"
+  );
+}
+
+add_task(async function testProfileCounter() {
+  setup();
+
+  info("Testing basic functionality, single install");
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+
+  // Fake another installation by resetting everything except for the profile
+  // count file.
+  reset(false);
+
+  info("Testing basic functionality, faking a second install");
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(2);
+
+  // Check if we properly handle the case where we cannot read from the file
+  // and we have already set its contents. This should report an error.
+  info("Testing read error after successful write");
+  gNextReadExceptionReason = ERROR_ACCESS_DENIED;
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  reset();
+
+  // A read error should cause an error to be reported, but should also write
+  // to the file in an attempt to fix it. So the next (successful) read should
+  // result in the correct telemetry.
+  info("Testing read error self-correction");
+  gNextReadExceptionReason = ERROR_ACCESS_DENIED;
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+
+  reset();
+
+  // If the file is malformed. We should report an error and fix it, then report
+  // the correct profile count next time.
+  info("Testing with malformed profile count file");
+  gFakeProfileCounterFile = "<malformed file data>";
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+
+  reset();
+
+  // If we haven't yet written to the file, a write error should cause an error
+  // to be reported.
+  info("Testing write error before the first write");
+  gNextWriteExceptionReason = ERROR_ACCESS_DENIED;
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  reset();
+
+  info("Testing bucketing");
+  // Fake 15 installations to drive the raw profile count up to 15.
+  for (let i = 0; i < 15; i++) {
+    reset(false);
+    await BrowserUsageTelemetry.reportProfileCount();
+  }
+  // With bucketing, values from 10-99 should all be reported as 10.
+  checkSuccess(10, 15);
+});
diff --git a/browser/modules/test/unit/test_Sanitizer_interrupted.js b/browser/modules/test/unit/test_Sanitizer_interrupted.js
new file mode 100644
index 0000000000..c8e7130ac0
--- /dev/null
+++ b/browser/modules/test/unit/test_Sanitizer_interrupted.js
@@ -0,0 +1,139 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+do_get_profile();
+
+// Test that interrupted sanitizations are properly tracked.
+
+add_task(async function () {
+  const { Sanitizer } = ChromeUtils.importESModule(
+    "resource:///modules/Sanitizer.sys.mjs"
+  );
+
+  Services.prefs.setBoolPref(Sanitizer.PREF_NEWTAB_SEGREGATION, false);
+
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN);
+    Services.prefs.clearUserPref(Sanitizer.PREF_SHUTDOWN_BRANCH + "formdata");
+    Services.prefs.clearUserPref(Sanitizer.PREF_NEWTAB_SEGREGATION);
+  });
+  Services.prefs.setBoolPref(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, true);
+  Services.prefs.setBoolPref(Sanitizer.PREF_SHUTDOWN_BRANCH + "formdata", true);
+
+  await Sanitizer.onStartup();
+  Assert.ok(Sanitizer.shouldSanitizeOnShutdown, "Should sanitize on shutdown");
+
+  let pendingSanitizations = JSON.parse(
+    Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]")
+  );
+  Assert.equal(
+    pendingSanitizations.length,
+    1,
+    "Should have 1 pending sanitization"
+  );
+  Assert.equal(
+    pendingSanitizations[0].id,
+    "shutdown",
+    "Should be the shutdown sanitization"
+  );
+  Assert.ok(
+    pendingSanitizations[0].itemsToClear.includes("formdata"),
+    "Pref has been setup"
+  );
+  Assert.ok(
+    !pendingSanitizations[0].options.isShutdown,
+    "Shutdown option is not present"
+  );
+
+  // Check the preference listeners.
+  Services.prefs.setBoolPref(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, false);
+  pendingSanitizations = JSON.parse(
+    Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]")
+  );
+  Assert.equal(
+    pendingSanitizations.length,
+    0,
+    "Should not have pending sanitizations"
+  );
+  Assert.ok(
+    !Sanitizer.shouldSanitizeOnShutdown,
+    "Should not sanitize on shutdown"
+  );
+  Services.prefs.setBoolPref(Sanitizer.PREF_SANITIZE_ON_SHUTDOWN, true);
+  pendingSanitizations = JSON.parse(
+    Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]")
+  );
+  Assert.equal(
+    pendingSanitizations.length,
+    1,
+    "Should have 1 pending sanitization"
+  );
+  Assert.equal(
+    pendingSanitizations[0].id,
+    "shutdown",
+    "Should be the shutdown sanitization"
+  );
+
+  Assert.ok(
+    pendingSanitizations[0].itemsToClear.includes("formdata"),
+    "Pending sanitizations should include formdata"
+  );
+  Services.prefs.setBoolPref(
+    Sanitizer.PREF_SHUTDOWN_BRANCH + "formdata",
+    false
+  );
+  pendingSanitizations = JSON.parse(
+    Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]")
+  );
+  Assert.equal(
+    pendingSanitizations.length,
+    1,
+    "Should have 1 pending sanitization"
+  );
+  Assert.ok(
+    !pendingSanitizations[0].itemsToClear.includes("formdata"),
+    "Pending sanitizations should have been updated"
+  );
+
+  // Check a sanitization properly rebuilds the pref.
+  await Sanitizer.sanitize(["formdata"]);
+  pendingSanitizations = JSON.parse(
+    Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]")
+  );
+  Assert.equal(
+    pendingSanitizations.length,
+    1,
+    "Should have 1 pending sanitization"
+  );
+  Assert.equal(
+    pendingSanitizations[0].id,
+    "shutdown",
+    "Should be the shutdown sanitization"
+  );
+
+  // Startup should run the pending one and setup a new shutdown sanitization.
+  Services.prefs.setBoolPref(
+    Sanitizer.PREF_SHUTDOWN_BRANCH + "formdata",
+    false
+  );
+  await Sanitizer.onStartup();
+  pendingSanitizations = JSON.parse(
+    Services.prefs.getStringPref(Sanitizer.PREF_PENDING_SANITIZATIONS, "[]")
+  );
+  Assert.equal(
+    pendingSanitizations.length,
+    1,
+    "Should have 1 pending sanitization"
+  );
+  Assert.equal(
+    pendingSanitizations[0].id,
+    "shutdown",
+    "Should be the shutdown sanitization"
+  );
+  Assert.ok(
+    !pendingSanitizations[0].itemsToClear.includes("formdata"),
+    "Pref has been setup"
+  );
+});
diff --git a/browser/modules/test/unit/test_SiteDataManager.js b/browser/modules/test/unit/test_SiteDataManager.js
new file mode 100644
index 0000000000..87bb511d1d
--- /dev/null
+++ b/browser/modules/test/unit/test_SiteDataManager.js
@@ -0,0 +1,278 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+// We intend to add tests that add real quota manager data to test
+// data size fetching in the new clear history dialog.
+// Bug 1874387 - Add a test to SiteDataManager to test data size display in the new clear
+// history dialog using real quota manager data
+
+ChromeUtils.defineESModuleGetters(this, {
+  SiteDataManager: "resource:///modules/SiteDataManager.sys.mjs",
+  SiteDataTestUtils: "resource://testing-common/SiteDataTestUtils.sys.mjs",
+  PermissionTestUtils: "resource://testing-common/PermissionTestUtils.sys.mjs",
+});
+
+const EXAMPLE_ORIGIN = "https://www.example.com";
+const EXAMPLE_ORIGIN_2 = "https://example.org";
+const EXAMPLE_ORIGIN_3 = "http://localhost:8000";
+
+let p =
+  Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+    EXAMPLE_ORIGIN
+  );
+let partitionKey = `(${p.scheme},${p.baseDomain})`;
+let EXAMPLE_ORIGIN_2_PARTITIONED =
+  Services.scriptSecurityManager.createContentPrincipal(
+    Services.io.newURI(EXAMPLE_ORIGIN_2),
+    {
+      partitionKey,
+    }
+  ).origin;
+
+add_task(function setup() {
+  do_get_profile();
+});
+
+add_task(async function testGetSites() {
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo1",
+    value: "bar1",
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo2",
+    value: "bar2",
+  });
+
+  // Cookie of EXAMPLE_ORIGIN_2 partitioned under EXAMPLE_ORIGIN.
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2_PARTITIONED,
+    name: "foo3",
+    value: "bar3",
+  });
+  // IndexedDB storage of EXAMPLE_ORIGIN_2 partitioned under EXAMPLE_ORIGIN.
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN, 4096);
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2_PARTITIONED, 4096);
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2,
+    name: "foo",
+    value: "bar",
+  });
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2, 2048);
+  await SiteDataTestUtils.persist(EXAMPLE_ORIGIN_2);
+
+  await SiteDataManager.updateSites();
+
+  let sites = await SiteDataManager.getSites();
+
+  let site1 = sites.find(site => site.baseDomain == "example.com");
+  let site2 = sites.find(site => site.baseDomain == "example.org");
+
+  Assert.equal(
+    site1.baseDomain,
+    "example.com",
+    "Has the correct base domain for example.com"
+  );
+  // 4096 partitioned + 4096 unpartitioned.
+  Assert.greater(site1.usage, 4096 * 2, "Has correct usage for example.com");
+  Assert.equal(site1.persisted, false, "example.com is not persisted");
+  Assert.equal(
+    site1.cookies.length,
+    3, // 2 top level, 1 partitioned.
+    "Has correct number of cookies for example.com"
+  );
+  Assert.ok(
+    typeof site1.lastAccessed.getDate == "function",
+    "lastAccessed for example.com is a Date"
+  );
+  Assert.ok(
+    site1.lastAccessed > Date.now() - 60 * 1000,
+    "lastAccessed for example.com happened recently"
+  );
+
+  Assert.equal(
+    site2.baseDomain,
+    "example.org",
+    "Has the correct base domain for example.org"
+  );
+  Assert.greater(site2.usage, 2048, "Has correct usage for example.org");
+  Assert.equal(site2.persisted, true, "example.org is persisted");
+  Assert.equal(
+    site2.cookies.length,
+    1,
+    "Has correct number of cookies for example.org"
+  );
+  Assert.ok(
+    typeof site2.lastAccessed.getDate == "function",
+    "lastAccessed for example.org is a Date"
+  );
+  Assert.ok(
+    site2.lastAccessed > Date.now() - 60 * 1000,
+    "lastAccessed for example.org happened recently"
+  );
+
+  await SiteDataTestUtils.clear();
+});
+
+add_task(async function testGetTotalUsage() {
+  await SiteDataManager.updateSites();
+  let sites = await SiteDataManager.getSites();
+  Assert.equal(sites.length, 0, "SiteDataManager is empty");
+
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN, 4096);
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2, 2048);
+
+  await SiteDataManager.updateSites();
+
+  let usage = await SiteDataManager.getTotalUsage();
+
+  Assert.greater(usage, 4096 + 2048, "Has the correct total usage.");
+
+  await SiteDataTestUtils.clear();
+});
+
+add_task(async function testRemove() {
+  await SiteDataManager.updateSites();
+
+  let uri = Services.io.newURI(EXAMPLE_ORIGIN);
+  PermissionTestUtils.add(uri, "camera", Services.perms.ALLOW_ACTION);
+
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo1",
+    value: "bar1",
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo2",
+    value: "bar2",
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2_PARTITIONED,
+    name: "foo3",
+    value: "bar3",
+  });
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN, 4096);
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2_PARTITIONED, 4096);
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2,
+    name: "foo",
+    value: "bar",
+  });
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2, 2048);
+  await SiteDataTestUtils.persist(EXAMPLE_ORIGIN_2);
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_3, 2048);
+
+  await SiteDataManager.updateSites();
+
+  let sites = await SiteDataManager.getSites();
+
+  Assert.equal(sites.length, 3, "Has three sites.");
+
+  await SiteDataManager.remove("localhost");
+
+  sites = await SiteDataManager.getSites();
+
+  Assert.equal(sites.length, 2, "Has two sites.");
+
+  await SiteDataManager.remove(["www.example.com"]);
+
+  sites = await SiteDataManager.getSites();
+
+  Assert.equal(sites.length, 1, "Has one site.");
+  Assert.equal(
+    sites[0].baseDomain,
+    "example.org",
+    "Has not cleared data for example.org"
+  );
+
+  let usage = await SiteDataTestUtils.getQuotaUsage(EXAMPLE_ORIGIN);
+  Assert.equal(usage, 0, "Has cleared quota usage for example.com");
+
+  let cookies = Services.cookies.countCookiesFromHost("example.com");
+  Assert.equal(cookies, 0, "Has cleared cookies for example.com");
+
+  let perm = PermissionTestUtils.testPermission(uri, "persistent-storage");
+  Assert.equal(
+    perm,
+    Services.perms.UNKNOWN_ACTION,
+    "Cleared the persistent-storage permission."
+  );
+  perm = PermissionTestUtils.testPermission(uri, "camera");
+  Assert.equal(
+    perm,
+    Services.perms.ALLOW_ACTION,
+    "Did not clear other permissions."
+  );
+
+  PermissionTestUtils.remove(uri, "camera");
+});
+
+add_task(async function testRemoveSiteData() {
+  let uri = Services.io.newURI(EXAMPLE_ORIGIN);
+  PermissionTestUtils.add(uri, "camera", Services.perms.ALLOW_ACTION);
+
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo1",
+    value: "bar1",
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo2",
+    value: "bar2",
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2_PARTITIONED,
+    name: "foo3",
+    value: "bar3",
+  });
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN, 4096);
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2_PARTITIONED, 4096);
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2,
+    name: "foo",
+    value: "bar",
+  });
+  await SiteDataTestUtils.addToIndexedDB(EXAMPLE_ORIGIN_2, 2048);
+  await SiteDataTestUtils.persist(EXAMPLE_ORIGIN_2);
+
+  await SiteDataManager.updateSites();
+
+  let sites = await SiteDataManager.getSites();
+
+  Assert.equal(sites.length, 2, "Has two sites.");
+
+  await SiteDataManager.removeSiteData();
+
+  sites = await SiteDataManager.getSites();
+
+  Assert.equal(sites.length, 0, "Has no sites.");
+
+  let usage = await SiteDataTestUtils.getQuotaUsage(EXAMPLE_ORIGIN);
+  Assert.equal(usage, 0, "Has cleared quota usage for example.com");
+
+  usage = await SiteDataTestUtils.getQuotaUsage(EXAMPLE_ORIGIN_2);
+  Assert.equal(usage, 0, "Has cleared quota usage for example.org");
+
+  let cookies = Services.cookies.countCookiesFromHost("example.org");
+  Assert.equal(cookies, 0, "Has cleared cookies for example.org");
+
+  let perm = PermissionTestUtils.testPermission(uri, "persistent-storage");
+  Assert.equal(
+    perm,
+    Services.perms.UNKNOWN_ACTION,
+    "Cleared the persistent-storage permission."
+  );
+  perm = PermissionTestUtils.testPermission(uri, "camera");
+  Assert.equal(
+    perm,
+    Services.perms.ALLOW_ACTION,
+    "Did not clear other permissions."
+  );
+
+  PermissionTestUtils.remove(uri, "camera");
+});
diff --git a/browser/modules/test/unit/test_SiteDataManagerContainers.js b/browser/modules/test/unit/test_SiteDataManagerContainers.js
new file mode 100644
index 0000000000..18bbb23262
--- /dev/null
+++ b/browser/modules/test/unit/test_SiteDataManagerContainers.js
@@ -0,0 +1,140 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { SiteDataManager } = ChromeUtils.importESModule(
+  "resource:///modules/SiteDataManager.sys.mjs"
+);
+const { SiteDataTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/SiteDataTestUtils.sys.mjs"
+);
+
+const EXAMPLE_ORIGIN = "https://www.example.com";
+const EXAMPLE_ORIGIN_2 = "https://example.org";
+
+add_task(function setup() {
+  do_get_profile();
+});
+
+add_task(async function testGetSitesByContainers() {
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo1",
+    value: "bar1",
+    originAttributes: { userContextId: "1" },
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo2",
+    value: "bar2",
+    originAttributes: { userContextId: "2" },
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN,
+    name: "foo3",
+    value: "bar3",
+    originAttributes: { userContextId: "2" },
+  });
+  SiteDataTestUtils.addToCookies({
+    origin: EXAMPLE_ORIGIN_2,
+    name: "foo",
+    value: "bar",
+    originAttributes: { userContextId: "3" },
+  });
+
+  await SiteDataTestUtils.addToIndexedDB(
+    EXAMPLE_ORIGIN + "^userContextId=1",
+    4096
+  );
+  await SiteDataTestUtils.addToIndexedDB(
+    EXAMPLE_ORIGIN_2 + "^userContextId=3",
+    2048
+  );
+
+  await SiteDataManager.updateSites();
+
+  let sites = await SiteDataManager.getSites();
+
+  let site1Container1 = sites
+    .find(site => site.baseDomain == "example.com")
+    .containersData.get(1);
+
+  let site1Container2 = sites
+    .find(site => site.baseDomain == "example.com")
+    .containersData.get(2);
+
+  let site2Container3 = sites
+    .find(site => site.baseDomain == "example.org")
+    .containersData.get(3);
+
+  Assert.equal(
+    sites.reduce(
+      (accumulator, site) => accumulator + site.containersData.size,
+      0
+    ),
+    3,
+    "Has the correct number of sites by containers"
+  );
+
+  Assert.equal(
+    site1Container1.cookiesBlocked,
+    1,
+    "Has the correct number of cookiesBlocked by containers"
+  );
+
+  Assert.greater(
+    site1Container1.quotaUsage,
+    4096,
+    "Has correct usage for example.com^userContextId=1"
+  );
+
+  Assert.ok(
+    typeof site1Container1.lastAccessed.getDate == "function",
+    "lastAccessed for example.com^userContextId=1 is a Date"
+  );
+  Assert.ok(
+    site1Container1.lastAccessed > Date.now() - 60 * 1000,
+    "lastAccessed for example.com^userContextId=1 happened recently"
+  );
+
+  Assert.equal(
+    site1Container2.cookiesBlocked,
+    2,
+    "Has the correct number of cookiesBlocked by containers"
+  );
+
+  Assert.equal(
+    site1Container2.quotaUsage,
+    0,
+    "Has correct usage for example.org^userContextId=2"
+  );
+
+  Assert.ok(
+    typeof site1Container2.lastAccessed.getDate == "function",
+    "lastAccessed for example.com^userContextId=2 is a Date"
+  );
+
+  Assert.equal(
+    site2Container3.cookiesBlocked,
+    1,
+    "Has the correct number of cookiesBlocked by containers"
+  );
+
+  Assert.greater(
+    site2Container3.quotaUsage,
+    2048,
+    "Has correct usage for example.org^userContextId=3"
+  );
+
+  Assert.ok(
+    typeof site2Container3.lastAccessed.getDate == "function",
+    "lastAccessed for example.org^userContextId=3 is a Date"
+  );
+  Assert.ok(
+    site2Container3.lastAccessed > Date.now() - 60 * 1000,
+    "lastAccessed for example.org^userContextId=3 happened recently"
+  );
+
+  await SiteDataTestUtils.clear();
+});
diff --git a/browser/modules/test/unit/test_SitePermissions.js b/browser/modules/test/unit/test_SitePermissions.js
new file mode 100644
index 0000000000..b5acfbb6f6
--- /dev/null
+++ b/browser/modules/test/unit/test_SitePermissions.js
@@ -0,0 +1,403 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { SitePermissions } = ChromeUtils.importESModule(
+  "resource:///modules/SitePermissions.sys.mjs"
+);
+
+const RESIST_FINGERPRINTING_ENABLED = Services.prefs.getBoolPref(
+  "privacy.resistFingerprinting"
+);
+const MIDI_ENABLED = Services.prefs.getBoolPref("dom.webmidi.enabled");
+
+const EXT_PROTOCOL_ENABLED = Services.prefs.getBoolPref(
+  "security.external_protocol_requires_permission"
+);
+
+const SPEAKER_SELECTION_ENABLED = Services.prefs.getBoolPref(
+  "media.setsinkid.enabled"
+);
+
+add_task(async function testPermissionsListing() {
+  let expectedPermissions = [
+    "autoplay-media",
+    "camera",
+    "cookie",
+    "desktop-notification",
+    "focus-tab-by-prompt",
+    "geo",
+    "install",
+    "microphone",
+    "popup",
+    "screen",
+    "shortcuts",
+    "persistent-storage",
+    "storage-access",
+    "xr",
+    "3rdPartyStorage",
+    "3rdPartyFrameStorage",
+  ];
+  if (RESIST_FINGERPRINTING_ENABLED) {
+    // Canvas permission should be hidden unless privacy.resistFingerprinting
+    // is true.
+    expectedPermissions.push("canvas");
+  }
+  if (MIDI_ENABLED) {
+    // Should remove this checking and add it as default after it is fully pref'd-on.
+    expectedPermissions.push("midi");
+    expectedPermissions.push("midi-sysex");
+  }
+  if (EXT_PROTOCOL_ENABLED) {
+    expectedPermissions.push("open-protocol-handler");
+  }
+  if (SPEAKER_SELECTION_ENABLED) {
+    expectedPermissions.push("speaker");
+  }
+  Assert.deepEqual(
+    SitePermissions.listPermissions().sort(),
+    expectedPermissions.sort(),
+    "Correct list of all permissions"
+  );
+});
+
+add_task(async function testGetAllByPrincipal() {
+  // check that it returns an empty array on an invalid principal
+  // like a principal with an about URI, which doesn't support site permissions
+  let wrongPrincipal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "about:config"
+    );
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(wrongPrincipal), []);
+
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), []);
+
+  SitePermissions.setForPrincipal(principal, "camera", SitePermissions.ALLOW);
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), [
+    {
+      id: "camera",
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+  ]);
+
+  SitePermissions.setForPrincipal(
+    principal,
+    "microphone",
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_SESSION
+  );
+  SitePermissions.setForPrincipal(
+    principal,
+    "desktop-notification",
+    SitePermissions.BLOCK
+  );
+
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), [
+    {
+      id: "camera",
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    {
+      id: "microphone",
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_SESSION,
+    },
+    {
+      id: "desktop-notification",
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+  ]);
+
+  SitePermissions.removeFromPrincipal(principal, "microphone");
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), [
+    {
+      id: "camera",
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    {
+      id: "desktop-notification",
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+  ]);
+
+  SitePermissions.removeFromPrincipal(principal, "camera");
+  SitePermissions.removeFromPrincipal(principal, "desktop-notification");
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), []);
+
+  Assert.equal(Services.prefs.getIntPref("permissions.default.shortcuts"), 0);
+  SitePermissions.setForPrincipal(
+    principal,
+    "shortcuts",
+    SitePermissions.BLOCK
+  );
+
+  // Customized preference should have been enabled, but the default should not.
+  Assert.equal(Services.prefs.getIntPref("permissions.default.shortcuts"), 0);
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), [
+    {
+      id: "shortcuts",
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+  ]);
+
+  SitePermissions.removeFromPrincipal(principal, "shortcuts");
+  Services.prefs.clearUserPref("permissions.default.shortcuts");
+});
+
+add_task(async function testGetAvailableStates() {
+  Assert.deepEqual(SitePermissions.getAvailableStates("camera"), [
+    SitePermissions.UNKNOWN,
+    SitePermissions.ALLOW,
+    SitePermissions.BLOCK,
+  ]);
+
+  // Test available states with a default permission set.
+  Services.prefs.setIntPref(
+    "permissions.default.camera",
+    SitePermissions.ALLOW
+  );
+  Assert.deepEqual(SitePermissions.getAvailableStates("camera"), [
+    SitePermissions.PROMPT,
+    SitePermissions.ALLOW,
+    SitePermissions.BLOCK,
+  ]);
+  Services.prefs.clearUserPref("permissions.default.camera");
+
+  Assert.deepEqual(SitePermissions.getAvailableStates("cookie"), [
+    SitePermissions.ALLOW,
+    SitePermissions.ALLOW_COOKIES_FOR_SESSION,
+    SitePermissions.BLOCK,
+  ]);
+
+  Assert.deepEqual(SitePermissions.getAvailableStates("popup"), [
+    SitePermissions.ALLOW,
+    SitePermissions.BLOCK,
+  ]);
+});
+
+add_task(async function testExactHostMatch() {
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+  let subPrincipal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://test1.example.com"
+    );
+
+  let exactHostMatched = [
+    "autoplay-media",
+    "desktop-notification",
+    "focus-tab-by-prompt",
+    "camera",
+    "microphone",
+    "screen",
+    "geo",
+    "xr",
+    "persistent-storage",
+  ];
+  if (RESIST_FINGERPRINTING_ENABLED) {
+    // Canvas permission should be hidden unless privacy.resistFingerprinting
+    // is true.
+    exactHostMatched.push("canvas");
+  }
+  if (MIDI_ENABLED) {
+    // WebMIDI is only pref'd on in nightly.
+    // Should remove this checking and add it as default after it is fully pref-on.
+    exactHostMatched.push("midi");
+    exactHostMatched.push("midi-sysex");
+  }
+  if (EXT_PROTOCOL_ENABLED) {
+    exactHostMatched.push("open-protocol-handler");
+  }
+  if (SPEAKER_SELECTION_ENABLED) {
+    exactHostMatched.push("speaker");
+  }
+  let nonExactHostMatched = [
+    "cookie",
+    "popup",
+    "install",
+    "shortcuts",
+    "storage-access",
+    "3rdPartyStorage",
+    "3rdPartyFrameStorage",
+  ];
+
+  let permissions = SitePermissions.listPermissions();
+  for (let permission of permissions) {
+    SitePermissions.setForPrincipal(
+      principal,
+      permission,
+      SitePermissions.ALLOW
+    );
+
+    if (exactHostMatched.includes(permission)) {
+      // Check that the sub-origin does not inherit the permission from its parent.
+      Assert.equal(
+        SitePermissions.getForPrincipal(subPrincipal, permission).state,
+        SitePermissions.getDefault(permission),
+        `${permission} should exact-host match`
+      );
+    } else if (nonExactHostMatched.includes(permission)) {
+      // Check that the sub-origin does inherit the permission from its parent.
+      Assert.equal(
+        SitePermissions.getForPrincipal(subPrincipal, permission).state,
+        SitePermissions.ALLOW,
+        `${permission} should not exact-host match`
+      );
+    } else {
+      Assert.ok(
+        false,
+        `Found an unknown permission ${permission} in exact host match test.` +
+          "Please add new permissions from SitePermissions.sys.mjs to this test."
+      );
+    }
+
+    // Check that the permission can be made specific to the sub-origin.
+    SitePermissions.setForPrincipal(
+      subPrincipal,
+      permission,
+      SitePermissions.PROMPT
+    );
+    Assert.equal(
+      SitePermissions.getForPrincipal(subPrincipal, permission).state,
+      SitePermissions.PROMPT
+    );
+    Assert.equal(
+      SitePermissions.getForPrincipal(principal, permission).state,
+      SitePermissions.ALLOW
+    );
+
+    SitePermissions.removeFromPrincipal(subPrincipal, permission);
+    SitePermissions.removeFromPrincipal(principal, permission);
+  }
+});
+
+add_task(async function testDefaultPrefs() {
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+
+  // Check that without a pref the default return value is UNKNOWN.
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "camera"), {
+    state: SitePermissions.UNKNOWN,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // Check that the default return value changed after setting the pref.
+  Services.prefs.setIntPref(
+    "permissions.default.camera",
+    SitePermissions.BLOCK
+  );
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "camera"), {
+    state: SitePermissions.BLOCK,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // Check that other permissions still return UNKNOWN.
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "microphone"), {
+    state: SitePermissions.UNKNOWN,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // Check that the default return value changed after changing the pref.
+  Services.prefs.setIntPref(
+    "permissions.default.camera",
+    SitePermissions.ALLOW
+  );
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "camera"), {
+    state: SitePermissions.ALLOW,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // Check that the preference is ignored if there is a value.
+  SitePermissions.setForPrincipal(principal, "camera", SitePermissions.BLOCK);
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "camera"), {
+    state: SitePermissions.BLOCK,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // The preference should be honored again, after resetting the permissions.
+  SitePermissions.removeFromPrincipal(principal, "camera");
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "camera"), {
+    state: SitePermissions.ALLOW,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+
+  // Should be UNKNOWN after clearing the pref.
+  Services.prefs.clearUserPref("permissions.default.camera");
+  Assert.deepEqual(SitePermissions.getForPrincipal(principal, "camera"), {
+    state: SitePermissions.UNKNOWN,
+    scope: SitePermissions.SCOPE_PERSISTENT,
+  });
+});
+
+add_task(async function testCanvasPermission() {
+  let resistFingerprinting = Services.prefs.getBoolPref(
+    "privacy.resistFingerprinting",
+    false
+  );
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "https://example.com"
+    );
+
+  SitePermissions.setForPrincipal(principal, "canvas", SitePermissions.ALLOW);
+
+  // Canvas permission is hidden when privacy.resistFingerprinting is false.
+  Services.prefs.setBoolPref("privacy.resistFingerprinting", false);
+  Assert.equal(SitePermissions.listPermissions().indexOf("canvas"), -1);
+  Assert.equal(
+    SitePermissions.getAllByPrincipal(principal).filter(
+      permission => permission.id === "canvas"
+    ).length,
+    0
+  );
+
+  // Canvas permission is visible when privacy.resistFingerprinting is true.
+  Services.prefs.setBoolPref("privacy.resistFingerprinting", true);
+  Assert.notEqual(SitePermissions.listPermissions().indexOf("canvas"), -1);
+  Assert.notEqual(
+    SitePermissions.getAllByPrincipal(principal).filter(
+      permission => permission.id === "canvas"
+    ).length,
+    0
+  );
+
+  SitePermissions.removeFromPrincipal(principal, "canvas");
+  Services.prefs.setBoolPref(
+    "privacy.resistFingerprinting",
+    resistFingerprinting
+  );
+});
+
+add_task(async function testFilePermissions() {
+  let principal =
+    Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+      "file:///example.js"
+    );
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), []);
+
+  SitePermissions.setForPrincipal(principal, "camera", SitePermissions.ALLOW);
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), [
+    {
+      id: "camera",
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+  ]);
+  SitePermissions.removeFromPrincipal(principal, "camera");
+  Assert.deepEqual(SitePermissions.getAllByPrincipal(principal), []);
+});
diff --git a/browser/modules/test/unit/test_SitePermissions_temporary.js b/browser/modules/test/unit/test_SitePermissions_temporary.js
new file mode 100644
index 0000000000..a91b1b8bd8
--- /dev/null
+++ b/browser/modules/test/unit/test_SitePermissions_temporary.js
@@ -0,0 +1,710 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { SitePermissions } = ChromeUtils.importESModule(
+  "resource:///modules/SitePermissions.sys.mjs"
+);
+
+const TemporaryPermissions = SitePermissions._temporaryPermissions;
+
+const PERM_A = "foo";
+const PERM_B = "bar";
+const PERM_C = "foobar";
+
+const BROWSER_A = createDummyBrowser("https://example.com/foo");
+const BROWSER_B = createDummyBrowser("https://example.org/foo");
+
+const EXPIRY_MS_A = 1000000;
+const EXPIRY_MS_B = 1000001;
+
+function createDummyBrowser(spec) {
+  let uri = Services.io.newURI(spec);
+  return {
+    currentURI: uri,
+    contentPrincipal: Services.scriptSecurityManager.createContentPrincipal(
+      uri,
+      {}
+    ),
+    dispatchEvent: () => {},
+    ownerGlobal: {
+      CustomEvent: class CustomEvent {},
+    },
+  };
+}
+
+function navigateDummyBrowser(browser, uri) {
+  // Callers may pass in either uri strings or nsIURI objects.
+  if (typeof uri == "string") {
+    uri = Services.io.newURI(uri);
+  }
+  browser.currentURI = uri;
+  browser.contentPrincipal =
+    Services.scriptSecurityManager.createContentPrincipal(
+      browser.currentURI,
+      {}
+    );
+}
+
+/**
+ * Tests that temporary permissions with different block states are stored
+ * (set, overwrite, delete) correctly.
+ */
+add_task(async function testAllowBlock() {
+  // Set two temporary permissions on the same browser.
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_A
+  );
+
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_B,
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_A
+  );
+
+  // Test that the permissions have been set correctly.
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, BROWSER_A),
+    {
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "SitePermissions returns expected permission state for perm A."
+  );
+
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_B, BROWSER_A),
+    {
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "SitePermissions returns expected permission state for perm B."
+  );
+
+  Assert.deepEqual(
+    TemporaryPermissions.get(BROWSER_A, PERM_A),
+    {
+      id: PERM_A,
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "TemporaryPermissions returns expected permission state for perm A."
+  );
+
+  Assert.deepEqual(
+    TemporaryPermissions.get(BROWSER_A, PERM_B),
+    {
+      id: PERM_B,
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "TemporaryPermissions returns expected permission state for perm B."
+  );
+
+  // Test internal data structure of TemporaryPermissions.
+  let entry = TemporaryPermissions._stateByBrowser.get(BROWSER_A);
+  ok(entry, "Should have an entry for browser A");
+  ok(
+    !TemporaryPermissions._stateByBrowser.has(BROWSER_B),
+    "Should have no entry for browser B"
+  );
+
+  let { browser, uriToPerm } = entry;
+  Assert.equal(
+    browser?.get(),
+    BROWSER_A,
+    "Entry should have a weak reference to the browser."
+  );
+
+  ok(uriToPerm, "Entry should have uriToPerm object.");
+  Assert.equal(Object.keys(uriToPerm).length, 2, "uriToPerm has 2 entries.");
+
+  let permissionsA = uriToPerm[BROWSER_A.contentPrincipal.origin];
+  let permissionsB =
+    uriToPerm[Services.eTLD.getBaseDomain(BROWSER_A.currentURI)];
+
+  ok(permissionsA, "Allow should be keyed under origin");
+  ok(permissionsB, "Block should be keyed under baseDomain");
+
+  let permissionA = permissionsA[PERM_A];
+  let permissionB = permissionsB[PERM_B];
+
+  Assert.equal(
+    permissionA.state,
+    SitePermissions.ALLOW,
+    "Should have correct state"
+  );
+  let expireTimeoutA = permissionA.expireTimeout;
+  Assert.ok(
+    Number.isInteger(expireTimeoutA),
+    "Should have valid expire timeout"
+  );
+
+  Assert.equal(
+    permissionB.state,
+    SitePermissions.BLOCK,
+    "Should have correct state"
+  );
+  let expireTimeoutB = permissionB.expireTimeout;
+  Assert.ok(
+    Number.isInteger(expireTimeoutB),
+    "Should have valid expire timeout"
+  );
+
+  // Overwrite permission A.
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_B
+  );
+
+  Assert.ok(
+    permissionsA[PERM_A].expireTimeout != expireTimeoutA,
+    "Overwritten permission A should have new timer"
+  );
+
+  // Overwrite permission B - this time with a non-block state which means it
+  // should be keyed by origin now.
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_B,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_A
+  );
+
+  let baseDomainEntry =
+    uriToPerm[Services.eTLD.getBaseDomain(BROWSER_A.currentURI)];
+  Assert.ok(
+    !baseDomainEntry || !baseDomainEntry[PERM_B],
+    "Should not longer have baseDomain permission entry"
+  );
+
+  permissionsB = uriToPerm[BROWSER_A.contentPrincipal.origin];
+  permissionB = permissionsB[PERM_B];
+  Assert.ok(
+    permissionsB && permissionB,
+    "Overwritten permission should be keyed under origin"
+  );
+  Assert.equal(
+    permissionB.state,
+    SitePermissions.ALLOW,
+    "Should have correct updated state"
+  );
+  Assert.ok(
+    permissionB.expireTimeout != expireTimeoutB,
+    "Overwritten permission B should have new timer"
+  );
+
+  // Remove permissions
+  SitePermissions.removeFromPrincipal(null, PERM_A, BROWSER_A);
+  SitePermissions.removeFromPrincipal(null, PERM_B, BROWSER_A);
+
+  // Test that permissions have been removed correctly
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, BROWSER_A),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "SitePermissions returns UNKNOWN state for A."
+  );
+
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_B, BROWSER_A),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "SitePermissions returns UNKNOWN state for B."
+  );
+
+  Assert.equal(
+    TemporaryPermissions.get(BROWSER_A, PERM_A),
+    null,
+    "TemporaryPermissions returns null for perm A."
+  );
+
+  Assert.equal(
+    TemporaryPermissions.get(BROWSER_A, PERM_B),
+    null,
+    "TemporaryPermissions returns null for perm B."
+  );
+});
+
+/**
+ * Tests TemporaryPermissions#getAll.
+ */
+add_task(async function testGetAll() {
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_A
+  );
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_B,
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_B,
+    EXPIRY_MS_A
+  );
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_C,
+    SitePermissions.PROMPT,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_B,
+    EXPIRY_MS_A
+  );
+
+  Assert.deepEqual(TemporaryPermissions.getAll(BROWSER_A), [
+    {
+      id: PERM_A,
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+  ]);
+
+  let permsBrowserB = TemporaryPermissions.getAll(BROWSER_B);
+  Assert.equal(
+    permsBrowserB.length,
+    2,
+    "There should be 2 permissions set for BROWSER_B"
+  );
+
+  let permB;
+  let permC;
+
+  if (permsBrowserB[0].id == PERM_B) {
+    permB = permsBrowserB[0];
+    permC = permsBrowserB[1];
+  } else {
+    permB = permsBrowserB[1];
+    permC = permsBrowserB[0];
+  }
+
+  Assert.deepEqual(permB, {
+    id: PERM_B,
+    state: SitePermissions.BLOCK,
+    scope: SitePermissions.SCOPE_TEMPORARY,
+  });
+  Assert.deepEqual(permC, {
+    id: PERM_C,
+    state: SitePermissions.PROMPT,
+    scope: SitePermissions.SCOPE_TEMPORARY,
+  });
+});
+
+/**
+ * Tests SitePermissions#clearTemporaryBlockPermissions and
+ * TemporaryPermissions#clear.
+ */
+add_task(async function testClear() {
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_A
+  );
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_B,
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_A
+  );
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_C,
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_B,
+    EXPIRY_MS_A
+  );
+
+  let stateByBrowser = SitePermissions._temporaryPermissions._stateByBrowser;
+
+  Assert.ok(stateByBrowser.has(BROWSER_A), "Browser map should have BROWSER_A");
+  Assert.ok(stateByBrowser.has(BROWSER_B), "Browser map should have BROWSER_B");
+
+  SitePermissions.clearTemporaryBlockPermissions(BROWSER_A);
+
+  // We only clear block permissions, so we should still see PERM_A.
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, BROWSER_A),
+    {
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "SitePermissions returns ALLOW state for PERM_A."
+  );
+  // We don't clear BROWSER_B so it should still be there.
+  Assert.ok(stateByBrowser.has(BROWSER_B), "Should still have BROWSER_B.");
+
+  // Now clear allow permissions for A explicitly.
+  SitePermissions._temporaryPermissions.clear(BROWSER_A, SitePermissions.ALLOW);
+
+  Assert.ok(!stateByBrowser.has(BROWSER_A), "Should no longer have BROWSER_A.");
+  let browser = stateByBrowser.get(BROWSER_B);
+  Assert.ok(browser, "Should still have BROWSER_B");
+
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, BROWSER_A),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "SitePermissions returns UNKNOWN state for PERM_A."
+  );
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_B, BROWSER_A),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "SitePermissions returns UNKNOWN state for PERM_B."
+  );
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_C, BROWSER_B),
+    {
+      state: SitePermissions.BLOCK,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "SitePermissions returns BLOCK state for PERM_C."
+  );
+
+  SitePermissions._temporaryPermissions.clear(BROWSER_B);
+
+  Assert.ok(!stateByBrowser.has(BROWSER_B), "Should no longer have BROWSER_B.");
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_C, BROWSER_B),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "SitePermissions returns UNKNOWN state for PERM_C."
+  );
+});
+
+/**
+ * Tests that the temporary permissions setter calls the callback on permission
+ * expire with the associated browser.
+ */
+add_task(async function testCallbackOnExpiry() {
+  let promiseExpireA = new Promise(resolve => {
+    TemporaryPermissions.set(
+      BROWSER_A,
+      PERM_A,
+      SitePermissions.BLOCK,
+      100,
+      undefined,
+      resolve
+    );
+  });
+  let promiseExpireB = new Promise(resolve => {
+    TemporaryPermissions.set(
+      BROWSER_B,
+      PERM_A,
+      SitePermissions.BLOCK,
+      100,
+      BROWSER_B.contentPrincipal,
+      resolve
+    );
+  });
+
+  let [browserA, browserB] = await Promise.all([
+    promiseExpireA,
+    promiseExpireB,
+  ]);
+  Assert.equal(
+    browserA,
+    BROWSER_A,
+    "Should get callback with browser on expiry for A"
+  );
+  Assert.equal(
+    browserB,
+    BROWSER_B,
+    "Should get callback with browser on expiry for B"
+  );
+});
+
+/**
+ * Tests that the temporary permissions setter calls the callback on permission
+ * expire with the associated browser if the browser associated browser has
+ * changed after setting the permission.
+ */
+add_task(async function testCallbackOnExpiryUpdatedBrowser() {
+  let promiseExpire = new Promise(resolve => {
+    TemporaryPermissions.set(
+      BROWSER_A,
+      PERM_A,
+      SitePermissions.BLOCK,
+      200,
+      undefined,
+      resolve
+    );
+  });
+
+  TemporaryPermissions.copy(BROWSER_A, BROWSER_B);
+
+  let browser = await promiseExpire;
+  Assert.equal(
+    browser,
+    BROWSER_B,
+    "Should get callback with updated browser on expiry."
+  );
+});
+
+/**
+ * Tests that the permission setter throws an exception if an invalid expiry
+ * time is passed.
+ */
+add_task(async function testInvalidExpiryTime() {
+  let expectedError = /expireTime must be a positive integer/;
+  Assert.throws(() => {
+    SitePermissions.setForPrincipal(
+      null,
+      PERM_A,
+      SitePermissions.ALLOW,
+      SitePermissions.SCOPE_TEMPORARY,
+      BROWSER_A,
+      null
+    );
+  }, expectedError);
+  Assert.throws(() => {
+    SitePermissions.setForPrincipal(
+      null,
+      PERM_A,
+      SitePermissions.ALLOW,
+      SitePermissions.SCOPE_TEMPORARY,
+      BROWSER_A,
+      0
+    );
+  }, expectedError);
+  Assert.throws(() => {
+    SitePermissions.setForPrincipal(
+      null,
+      PERM_A,
+      SitePermissions.ALLOW,
+      SitePermissions.SCOPE_TEMPORARY,
+      BROWSER_A,
+      -100
+    );
+  }, expectedError);
+});
+
+/**
+ * Tests that we block by base domain but allow by origin.
+ */
+add_task(async function testTemporaryPermissionScope() {
+  let states = {
+    strict: {
+      same: [
+        "https://example.com",
+        "https://example.com/sub/path",
+        "https://example.com:443",
+        "https://name:password@example.com",
+      ],
+      different: [
+        "https://example.com",
+        "https://test1.example.com",
+        "http://example.com",
+        "http://example.org",
+        "file:///tmp/localPageA.html",
+        "file:///tmp/localPageB.html",
+      ],
+    },
+    nonStrict: {
+      same: [
+        "https://example.com",
+        "https://example.com/sub/path",
+        "https://example.com:443",
+        "https://test1.example.com",
+        "http://test2.test1.example.com",
+        "https://name:password@example.com",
+        "http://example.com",
+      ],
+      different: [
+        "https://example.com",
+        "https://example.org",
+        "http://example.net",
+      ],
+    },
+  };
+
+  for (let state of [SitePermissions.BLOCK, SitePermissions.ALLOW]) {
+    let matchStrict = state != SitePermissions.BLOCK;
+
+    let lists = matchStrict ? states.strict : states.nonStrict;
+
+    Object.entries(lists).forEach(([type, list]) => {
+      let expectSet = type == "same";
+
+      for (let uri of list) {
+        let browser = createDummyBrowser(uri);
+        SitePermissions.setForPrincipal(
+          null,
+          PERM_A,
+          state,
+          SitePermissions.SCOPE_TEMPORARY,
+          browser,
+          EXPIRY_MS_A
+        );
+
+        ok(true, "origin:" + browser.contentPrincipal.origin);
+
+        for (let otherUri of list) {
+          if (uri == otherUri) {
+            continue;
+          }
+          navigateDummyBrowser(browser, otherUri);
+          ok(true, "new origin:" + browser.contentPrincipal.origin);
+
+          Assert.deepEqual(
+            SitePermissions.getForPrincipal(null, PERM_A, browser),
+            {
+              state: expectSet ? state : SitePermissions.UNKNOWN,
+              scope: expectSet
+                ? SitePermissions.SCOPE_TEMPORARY
+                : SitePermissions.SCOPE_PERSISTENT,
+            },
+            `${
+              state == SitePermissions.BLOCK ? "Block" : "Allow"
+            } Permission originally set for ${uri} should ${
+              expectSet ? "not" : "also"
+            } be set for ${otherUri}.`
+          );
+        }
+
+        SitePermissions._temporaryPermissions.clear(browser);
+      }
+    });
+  }
+});
+
+/**
+ * Tests that we can override the principal to use for keying temporary
+ * permissions.
+ */
+add_task(async function testOverrideBrowserURI() {
+  let testBrowser = createDummyBrowser("https://old.example.com/foo");
+  let overrideURI = Services.io.newURI("https://test.example.org/test/path");
+  SitePermissions.setForPrincipal(
+    Services.scriptSecurityManager.createContentPrincipal(overrideURI, {}),
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    testBrowser,
+    EXPIRY_MS_A
+  );
+
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, testBrowser),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "Permission should not be set for old URI."
+  );
+
+  // "Navigate" to new URI
+  navigateDummyBrowser(testBrowser, overrideURI);
+
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, testBrowser),
+    {
+      state: SitePermissions.ALLOW,
+      scope: SitePermissions.SCOPE_TEMPORARY,
+    },
+    "Permission should be set for new URI."
+  );
+
+  SitePermissions._temporaryPermissions.clear(testBrowser);
+});
+
+/**
+ * Tests that TemporaryPermissions does not throw for incompatible URI or
+ * browser.currentURI.
+ */
+add_task(async function testPermissionUnsupportedScheme() {
+  let aboutURI = Services.io.newURI("about:blank");
+
+  // Incompatible override URI should not throw or store any permissions.
+  SitePermissions.setForPrincipal(
+    Services.scriptSecurityManager.createContentPrincipal(aboutURI, {}),
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    BROWSER_A,
+    EXPIRY_MS_B
+  );
+  Assert.ok(
+    SitePermissions._temporaryPermissions._stateByBrowser.has(BROWSER_A),
+    "Should not have stored permission for unsupported URI scheme."
+  );
+
+  let browser = createDummyBrowser("https://example.com/");
+  // Set a permission so we get an entry in the browser map.
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_B,
+    SitePermissions.BLOCK,
+    SitePermissions.SCOPE_TEMPORARY,
+    browser
+  );
+
+  // Change browser URI to about:blank.
+  navigateDummyBrowser(browser, aboutURI);
+
+  // Setting permission for browser with unsupported URI should not throw.
+  SitePermissions.setForPrincipal(
+    null,
+    PERM_A,
+    SitePermissions.ALLOW,
+    SitePermissions.SCOPE_TEMPORARY,
+    browser
+  );
+  Assert.ok(true, "Set should not throw for unsupported URI");
+
+  SitePermissions.removeFromPrincipal(null, PERM_A, browser);
+  Assert.ok(true, "Remove should not throw for unsupported URI");
+
+  Assert.deepEqual(
+    SitePermissions.getForPrincipal(null, PERM_A, browser),
+    {
+      state: SitePermissions.UNKNOWN,
+      scope: SitePermissions.SCOPE_PERSISTENT,
+    },
+    "Should return no permission set for unsupported URI."
+  );
+  Assert.ok(true, "Get should not throw for unsupported URI");
+
+  // getAll should not throw, but return empty permissions array.
+  let permissions = SitePermissions.getAllForBrowser(browser);
+  Assert.ok(
+    Array.isArray(permissions) && !permissions.length,
+    "Should return empty array for browser on about:blank"
+  );
+
+  SitePermissions._temporaryPermissions.clear(browser);
+});
diff --git a/browser/modules/test/unit/test_TabUnloader.js b/browser/modules/test/unit/test_TabUnloader.js
new file mode 100644
index 0000000000..3d125828bb
--- /dev/null
+++ b/browser/modules/test/unit/test_TabUnloader.js
@@ -0,0 +1,449 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { TabUnloader } = ChromeUtils.importESModule(
+  "resource:///modules/TabUnloader.sys.mjs"
+);
+
+let TestTabUnloaderMethods = {
+  isNonDiscardable(tab, weight) {
+    return /\bselected\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  isParentProcess(tab, weight) {
+    return /\bparent\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  isPinned(tab, weight) {
+    return /\bpinned\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  isLoading(tab, weight) {
+    return /\bloading\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  usingPictureInPicture(tab, weight) {
+    return /\bpictureinpicture\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  playingMedia(tab, weight) {
+    return /\bmedia\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  usingWebRTC(tab, weight) {
+    return /\bwebrtc\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  isPrivate(tab, weight) {
+    return /\bprivate\b/.test(tab.keywords) ? weight : 0;
+  },
+
+  getMinTabCount() {
+    // Use a low number for testing.
+    return 3;
+  },
+
+  getNow() {
+    return 100;
+  },
+
+  *iterateProcesses(tab) {
+    for (let process of tab.process.split(",")) {
+      yield Number(process);
+    }
+  },
+
+  async calculateMemoryUsage(processMap, tabs) {
+    let memory = tabs[0].memory;
+    for (let pid of processMap.keys()) {
+      processMap.get(pid).memory = memory ? memory[pid - 1] : 1;
+    }
+  },
+};
+
+let unloadTests = [
+  // Each item in the array represents one test. The test is a subarray
+  // containing an element per tab. This is a string of keywords that
+  // identify which criteria apply. The first part of the string may contain
+  // a number that represents the last visit time, where higher numbers
+  // are later. The last element in the subarray is special and identifies
+  // the expected order of the tabs sorted by weight. The first tab in
+  // this list is the one that is expected to selected to be discarded.
+  { tabs: ["1 selected", "2", "3"], result: "1,2,0" },
+  { tabs: ["1", "2 selected", "3"], result: "0,2,1" },
+  { tabs: ["1 selected", "2", "3"], process: ["1", "2", "3"], result: "1,2,0" },
+  {
+    tabs: ["1 selected", "2 selected", "3 selected"],
+    process: ["1", "2", "3"],
+    result: "0,1,2",
+  },
+  {
+    tabs: ["1 selected", "2", "3"],
+    process: ["1,2,3", "2", "3"],
+    result: "1,2,0",
+  },
+  {
+    tabs: ["9", "8", "6", "5 selected", "2", "3", "4", "1"],
+    result: "7,4,5,6,2,1,0,3",
+  },
+  {
+    tabs: ["9", "8 pinned", "6", "5 selected", "2", "3 pinned", "4", "1"],
+    result: "7,4,6,2,0,5,1,3",
+  },
+  {
+    tabs: [
+      "9",
+      "8 pinned",
+      "6",
+      "5 selected pinned",
+      "2",
+      "3 pinned",
+      "4",
+      "1",
+    ],
+    result: "7,4,6,2,0,5,1,3",
+  },
+  {
+    tabs: [
+      "9",
+      "8 pinned",
+      "6",
+      "5 selected pinned",
+      "2",
+      "3 selected pinned",
+      "4",
+      "1",
+    ],
+    result: "7,4,6,2,0,1,5,3",
+  },
+  {
+    tabs: ["1", "2 selected", "3", "4 media", "5", "6"],
+    result: "0,2,4,5,1,3",
+  },
+  {
+    tabs: ["1 media", "2 selected media", "3", "4 media", "5", "6"],
+    result: "2,4,5,0,3,1",
+  },
+  {
+    tabs: ["1 media", "2 media pinned", "3", "4 media", "5 pinned", "6"],
+    result: "2,5,4,0,3,1",
+  },
+  {
+    tabs: [
+      "1 media",
+      "2 media pinned",
+      "3",
+      "4 media",
+      "5 media pinned",
+      "6 selected",
+    ],
+    result: "2,0,3,5,1,4",
+  },
+  {
+    tabs: [
+      "10 selected",
+      "20 private",
+      "30 webrtc",
+      "40 pictureinpicture",
+      "50 loading pinned",
+      "60",
+    ],
+    result: "5,4,0,1,2,3",
+  },
+  {
+    // Since TestTabUnloaderMethods.getNow() returns 100 and the test
+    // passes minInactiveDuration = 0 to TabUnloader.getSortedTabs(),
+    // tab 200 and 300 are excluded from the result.
+    tabs: ["300", "10", "50", "100", "200"],
+    result: "1,2,3",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6"],
+    process: ["1", "2", "1", "1", "1", "1"],
+    result: "1,0,2,3,4,5",
+  },
+  {
+    tabs: ["1", "2 selected", "3", "4", "5", "6"],
+    process: ["1", "2", "1", "1", "1", "1"],
+    result: "0,2,3,4,5,1",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6"],
+    process: ["1", "2", "2", "1", "1", "1"],
+    result: "0,1,2,3,4,5",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6"],
+    process: ["1", "2", "3", "1", "1", "1"],
+    result: "1,0,2,3,4,5",
+  },
+  {
+    tabs: ["1", "2 media", "3", "4", "5", "6"],
+    process: ["1", "2", "3", "1", "1", "1"],
+    result: "2,0,3,4,5,1",
+  },
+  {
+    tabs: ["1", "2 media", "3", "4", "5", "6"],
+    process: ["1", "2", "3", "1", "1,2,3", "1"],
+    result: "0,2,3,4,5,1",
+  },
+  {
+    tabs: ["1", "2 media", "3", "4", "5", "6"],
+    process: ["1", "2", "3", "1", "1,4,5", "1"],
+    result: "2,0,3,4,5,1",
+  },
+  {
+    tabs: ["1", "2 media", "3 media", "4", "5 media", "6"],
+    process: ["1", "2", "3", "1", "1,4,5", "1"],
+    result: "0,3,5,1,2,4",
+  },
+  {
+    tabs: ["1", "2 media", "3 media", "4", "5 media", "6"],
+    process: ["1", "1", "3", "1", "1,4,5", "1"],
+    result: "0,3,5,1,2,4",
+  },
+  {
+    tabs: ["1", "2 media", "3 media", "4", "5 media", "6"],
+    process: ["1", "2", "3", "4", "1,4,5", "5"],
+    result: "0,3,5,1,2,4",
+  },
+  {
+    tabs: ["1", "2 media", "3 media", "4", "5 media", "6"],
+    process: ["1", "1", "3", "4", "1,4,5", "5"],
+    result: "0,3,5,1,2,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6"],
+    process: ["1", "1", "1", "2", "1,3,4,5,6,7,8", "1"],
+    result: "0,1,2,3,4,5",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["1", "1", "1", "2", "1,3,4,5,6,7,8", "1", "1", "1"],
+    result: "4,0,3,1,2,5,6,7",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 selected", "6"],
+    process: ["1", "1", "1", "2", "1,3,4,5,6,7,8", "1"],
+    result: "0,1,2,3,5,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6"],
+    process: ["1", "1", "1", "2", "1,3,4,5,6,7,8", "1"],
+    result: "0,1,2,3,5,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1", "1", "2", "1,3,4,5,6,7,8", "1", "1", "1"],
+    result: "0,3,1,2,5,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1,3,4,5,6,7,8", "1", "1", "1", "1", "1", "1"],
+    result: "1,0,2,3,5,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1", "1,3,4,5,6,7,8", "1", "1", "1", "1", "1"],
+    result: "2,0,1,3,5,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1", "1,1,1,1,1,1,1", "1", "1", "1", "1,1,1,1,1", "1"],
+    result: "0,1,2,3,5,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1", "1,2,3,4,5", "1", "1", "1", "1,2,3,4,5", "1"],
+    result: "0,1,2,3,5,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1", "1,6", "1", "1", "1", "1,2,3,4,5", "1"],
+    result: "0,2,1,3,5,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1", "1", "1,6", "1,7", "1,8", "1,9", "1,2,3,4,5", "1"],
+    result: "2,3,0,5,1,6,7,4",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5 media", "6", "7", "8"],
+    process: ["1,10,11", "1", "1,2", "1,7", "1,8", "1,9", "1,2,3,4,5", "1"],
+    result: "0,3,1,5,2,6,7,4",
+  },
+  {
+    tabs: [
+      "1 media",
+      "2 media",
+      "3 media",
+      "4 media",
+      "5 media",
+      "6",
+      "7",
+      "8",
+    ],
+    process: ["1,10,11", "1", "1,2", "1,7", "1,8", "1,9", "1,2,3,4,5", "1"],
+    result: "6,5,7,0,1,2,3,4",
+  },
+  {
+    tabs: ["1", "2", "3"],
+    process: ["1", "2", "3"],
+    memory: ["100", "200", "300"],
+    result: "0,1,2",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"],
+    process: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"],
+    memory: [
+      "100",
+      "200",
+      "300",
+      "400",
+      "500",
+      "600",
+      "700",
+      "800",
+      "900",
+      "1000",
+    ],
+    result: "0,1,2,3,4,5,6,7,8,9",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"],
+    process: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"],
+    memory: [
+      "100",
+      "900",
+      "300",
+      "500",
+      "400",
+      "700",
+      "600",
+      "1000",
+      "200",
+      "200",
+    ],
+    result: "1,0,2,3,5,4,6,7,8,9",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"],
+    process: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"],
+    memory: [
+      "1000",
+      "900",
+      "300",
+      "500",
+      "400",
+      "1000",
+      "600",
+      "1000",
+      "200",
+      "200",
+    ],
+    result: "0,1,2,3,5,4,6,7,8,9",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6"],
+    process: ["1", "2,7", "3", "4", "5", "6"],
+    memory: ["100", "200", "300", "400", "500", "600", "700"],
+    result: "1,0,2,3,4,5",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["1,6", "2,7", "3,8", "4,1,2", "5", "6", "7", "8"],
+    memory: ["100", "200", "300", "400", "500", "600", "700", "800"],
+    result: "2,3,0,1,4,5,6,7",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["1", "1", "1", "2", "1", "1", "1", "1"],
+    memory: ["700", "1000"],
+    result: "0,3,1,2,4,5,6,7",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["1", "1", "1", "1", "2,1", "2,1", "3", "3"],
+    memory: ["1000", "2000", "3000"],
+    result: "0,1,2,4,3,5,6,7",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["2", "2", "2", "2", "2,1", "2,1", "3", "3"],
+    memory: ["1000", "600", "1000"],
+    result: "0,1,2,4,3,5,6,7",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["1", "1", "1", "2", "2,1,1,1", "2,1", "3", "3"],
+    memory: ["1000", "1800", "1000"],
+    result: "0,1,3,2,4,5,6,7",
+  },
+  {
+    tabs: ["1", "2", "3", "4", "5", "6", "7", "8"],
+    process: ["1", "1", "1", "2", "2,1,1,1", "2,1", "3", "3"],
+    memory: ["4000", "1800", "1000"],
+    result: "0,1,2,4,3,5,6,7",
+  },
+  {
+    // The tab "1" contains 4 frames, but its uniqueCount is 1 because
+    // all of those frames are backed by the process "1".  As a result,
+    // TabUnloader puts the tab "1" first based on the last access time.
+    tabs: ["1", "2", "3", "4", "5"],
+    process: ["1,1,1,1", "2", "3", "3", "3"],
+    memory: ["100", "100", "100"],
+    result: "0,1,2,3,4",
+  },
+  {
+    // The uniqueCount of the tab "1", "2", and "3" is 1, 2, and 3,
+    // respectively.  As a result the first three tabs are sorted as 2,1,0.
+    tabs: ["1", "2", "3", "4", "5", "6"],
+    process: ["1,7,1,7,1,1,7,1", "7,3,7,2", "4,5,7,4,6,7", "7", "7", "7"],
+    memory: ["100", "100", "100", "100", "100", "100", "100"],
+    result: "2,1,0,3,4,5",
+  },
+];
+
+let globalBrowser = {
+  discardBrowser() {
+    return true;
+  },
+};
+
+add_task(async function doTests() {
+  for (let test of unloadTests) {
+    function* iterateTabs() {
+      let tabs = test.tabs;
+      for (let t = 0; t < tabs.length; t++) {
+        let tab = {
+          tab: {
+            originalIndex: t,
+            lastAccessed: Number(/^[0-9]+/.exec(tabs[t])[0]),
+            keywords: tabs[t],
+            process: "process" in test ? test.process[t] : "1",
+          },
+          memory: test.memory,
+          gBrowser: globalBrowser,
+        };
+        yield tab;
+      }
+    }
+    TestTabUnloaderMethods.iterateTabs = iterateTabs;
+
+    let expectedOrder = "";
+    const sortedTabs = await TabUnloader.getSortedTabs(
+      0,
+      TestTabUnloaderMethods
+    );
+    for (let tab of sortedTabs) {
+      if (expectedOrder) {
+        expectedOrder += ",";
+      }
+      expectedOrder += tab.tab.originalIndex;
+    }
+
+    Assert.equal(expectedOrder, test.result);
+  }
+});
diff --git a/browser/modules/test/unit/test_discovery.js b/browser/modules/test/unit/test_discovery.js
new file mode 100644
index 0000000000..08f67273a6
--- /dev/null
+++ b/browser/modules/test/unit/test_discovery.js
@@ -0,0 +1,143 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+"use strict";
+
+// ClientID fails without...
+do_get_profile();
+
+const { TestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TestUtils.sys.mjs"
+);
+const { ClientID } = ChromeUtils.importESModule(
+  "resource://gre/modules/ClientID.sys.mjs"
+);
+const { Discovery } = ChromeUtils.importESModule(
+  "resource:///modules/Discovery.sys.mjs"
+);
+const { ContextualIdentityService } = ChromeUtils.importESModule(
+  "resource://gre/modules/ContextualIdentityService.sys.mjs"
+);
+
+const TAAR_COOKIE_NAME = "taarId";
+
+add_task(async function test_discovery() {
+  let uri = Services.io.newURI("https://example.com/foobar");
+
+  // Ensure the prefs we need
+  Services.prefs.setBoolPref("browser.discovery.enabled", true);
+  Services.prefs.setBoolPref("browser.discovery.containers.enabled", true);
+  Services.prefs.setBoolPref("datareporting.healthreport.uploadEnabled", true);
+  Services.prefs.setCharPref("browser.discovery.sites", uri.host);
+
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref("browser.discovery.enabled");
+    Services.prefs.clearUserPref("browser.discovery.containers.enabled");
+    Services.prefs.clearUserPref("browser.discovery.sites");
+    Services.prefs.clearUserPref("datareporting.healthreport.uploadEnabled");
+  });
+
+  // This is normally initialized by telemetry, force id creation.  This results
+  // in Discovery setting the cookie.
+  await ClientID.getClientID();
+  await Discovery.update();
+
+  ok(
+    Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {}),
+    "cookie exists"
+  );
+  ok(
+    !Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {
+      privateBrowsingId: 1,
+    }),
+    "no private cookie exists"
+  );
+  ContextualIdentityService.getPublicIdentities().forEach(identity => {
+    let { userContextId } = identity;
+    equal(
+      Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {
+        userContextId,
+      }),
+      identity.public,
+      "cookie exists"
+    );
+  });
+
+  // Test the addition of a new container.
+  let changed = TestUtils.topicObserved("cookie-changed", subject => {
+    let cookie = subject
+      .QueryInterface(Ci.nsICookieNotification)
+      .cookie.QueryInterface(Ci.nsICookie);
+    equal(cookie.name, TAAR_COOKIE_NAME, "taar cookie exists");
+    equal(cookie.host, uri.host, "cookie exists for host");
+    equal(
+      cookie.originAttributes.userContextId,
+      container.userContextId,
+      "cookie userContextId is correct"
+    );
+    return true;
+  });
+  let container = ContextualIdentityService.create(
+    "New Container",
+    "Icon",
+    "Color"
+  );
+  await changed;
+
+  // Test disabling
+  Discovery.enabled = false;
+  // Wait for the update to remove the cookie.
+  await TestUtils.waitForCondition(() => {
+    return !Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {});
+  });
+
+  ContextualIdentityService.getPublicIdentities().forEach(identity => {
+    let { userContextId } = identity;
+    ok(
+      !Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {
+        userContextId,
+      }),
+      "no cookie exists"
+    );
+  });
+
+  // turn off containers
+  Services.prefs.setBoolPref("browser.discovery.containers.enabled", false);
+
+  Discovery.enabled = true;
+  await TestUtils.waitForCondition(() => {
+    return Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {});
+  });
+  // make sure we did not set cookies on containers
+  ContextualIdentityService.getPublicIdentities().forEach(identity => {
+    let { userContextId } = identity;
+    ok(
+      !Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {
+        userContextId,
+      }),
+      "no cookie exists"
+    );
+  });
+
+  // Make sure clientId changes update discovery
+  changed = TestUtils.topicObserved("cookie-changed", subject => {
+    let notification = subject.QueryInterface(Ci.nsICookieNotification);
+    if (notification.action != Ci.nsICookieNotification.COOKIE_ADDED) {
+      return false;
+    }
+    let cookie = notification.cookie.QueryInterface(Ci.nsICookie);
+    equal(cookie.name, TAAR_COOKIE_NAME, "taar cookie exists");
+    equal(cookie.host, uri.host, "cookie exists for host");
+    return true;
+  });
+  await ClientID.removeClientID();
+  await ClientID.getClientID();
+  await changed;
+
+  // Make sure disabling telemetry disables discovery.
+  Services.prefs.setBoolPref("datareporting.healthreport.uploadEnabled", false);
+  await TestUtils.waitForCondition(() => {
+    return !Services.cookies.cookieExists(uri.host, "/", TAAR_COOKIE_NAME, {});
+  });
+});
diff --git a/browser/modules/test/unit/xpcshell.toml b/browser/modules/test/unit/xpcshell.toml
new file mode 100644
index 0000000000..1738e92194
--- /dev/null
+++ b/browser/modules/test/unit/xpcshell.toml
@@ -0,0 +1,32 @@
+[DEFAULT]
+head =  ''
+firefox-appdir = "browser"
+skip-if = ["os == 'android'"] # bug 1730213
+
+["test_E10SUtils_nested_URIs.js"]
+
+["test_HomePage.js"]
+
+["test_HomePage_ignore.js"]
+
+["test_InstallationTelemetry.js"]
+run-if = ["os == 'win'"] # Test of a Windows-specific feature
+
+["test_LaterRun.js"]
+
+["test_ProfileCounter.js"]
+run-if = ["os == 'win'"] # Test of a Windows-specific feature
+
+["test_Sanitizer_interrupted.js"]
+
+["test_SiteDataManager.js"]
+
+["test_SiteDataManagerContainers.js"]
+
+["test_SitePermissions.js"]
+
+["test_SitePermissions_temporary.js"]
+
+["test_TabUnloader.js"]
+
+["test_discovery.js"]
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-19 00:47:55 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-19 00:47:55 +0000
commit	26a029d407be480d791972afb5975cf62c9360a6 (patch)
tree	f435a8308119effd964b339f76abb83a57c29483 /browser/modules/test
parent	Initial commit. (diff)
download	firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip