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/* 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 */
"use strict";
const EXPORTED_SYMBOLS = ["RecommendedPreferences"];
const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const { XPCOMUtils } = ChromeUtils.import(
const lazy = {};
XPCOMUtils.defineLazyModuleGetters(lazy, {
XPCOMUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
// Ensure we are in the parent process.
if (Services.appinfo.processType != Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT) {
throw new Error(
"RecommendedPreferences should only be loaded in the parent process"
// Preferences are set for automation on startup, unless
// remote.prefs.recommended has been set to false.
// All prefs listed here have immediate effect, and don't require a restart
// nor have to be set in the profile before the application starts. If such a
// latter preference has to be added, it needs to be done for the client like
// Marionette client (, or geckodriver (
// Note: Clients do not always use the latest version of the application. As
// such backward compatibility has to be ensured at least for the last three
// releases.
const COMMON_PREFERENCES = new Map([
// Make sure Shield doesn't hit the network.
["app.normandy.api_url", ""],
// Disable automatically upgrading Firefox
// Note: This preference should have already been set by the client when
// creating the profile. But if not and to absolutely make sure that updates
// of Firefox aren't downloaded and applied, enforce its presence.
["app.update.disabledForTesting", true],
// Increase the APZ content response timeout in tests to 1 minute.
// This is to accommodate the fact that test environments tends to be
// slower than production environments (with the b2g emulator being
// the slowest of them all), resulting in the production timeout value
// sometimes being exceeded and causing false-positive test failures.
["apz.content_response_timeout", 60000],
// Don't show the content blocking introduction panel.
// We use a larger number than the default 22 to have some buffer
// This can be removed once Firefox 69 and 68 ESR and are no longer supported.
["browser.contentblocking.introCount", 99],
// Indicate that the download panel has been shown once so that
// whichever download test runs first doesn't show the popup
// inconsistently.
["", true],
// Always display a blank page
["browser.newtabpage.enabled", false],
// Background thumbnails in particular cause grief, and disabling
// thumbnails in general cannot hurt
["browser.pagethumbnails.capturing_disabled", true],
// Disable safebrowsing components.
// These should also be set in the profile prior to starting Firefox,
// as it is picked up at runtime.
["browser.safebrowsing.blockedURIs.enabled", false],
["browser.safebrowsing.downloads.enabled", false],
["browser.safebrowsing.passwords.enabled", false],
["browser.safebrowsing.malware.enabled", false],
["browser.safebrowsing.phishing.enabled", false],
// Disable updates to search engines.
// Should be set in profile.
["", false],
// Do not restore the last open set of tabs if the browser has crashed
["browser.sessionstore.resume_from_crash", false],
// Don't check for the default web browser during startup.
// These should also be set in the profile prior to starting Firefox,
// as it is picked up at runtime.
["", false],
// Disable session restore infobar
["browser.startup.couldRestoreSession.count", -1],
// Do not redirect user when a milstone upgrade of Firefox is detected
["browser.startup.homepage_override.mstone", "ignore"],
// Do not close the window when the last tab gets closed
["browser.tabs.closeWindowWithLastTab", false],
// Do not allow background tabs to be zombified on Android, otherwise for
// tests that open additional tabs, the test harness tab itself might get
// unloaded
["browser.tabs.disableBackgroundZombification", false],
// Don't unload tabs when available memory is running low
["browser.tabs.unloadOnLowMemory", false],
// Do not warn when closing all open tabs
["browser.tabs.warnOnClose", false],
// Do not warn when closing all other open tabs
["browser.tabs.warnOnCloseOtherTabs", false],
// Do not warn when multiple tabs will be opened
["browser.tabs.warnOnOpen", false],
// Don't show the Bookmarks Toolbar on any tab (the above pref that
// disables the New Tab Page ends up showing the toolbar on about:blank).
["browser.toolbars.bookmarks.visibility", "never"],
// Disable first run splash page on Windows 10
["browser.usedOnWindows10.introURL", ""],
// Disable the UI tour.
// Should be set in profile.
["browser.uitour.enabled", false],
// Turn off Merino suggestions in the location bar so as not to trigger
// network connections.
["browser.urlbar.merino.endpointURL", ""],
// Turn off search suggestions in the location bar so as not to trigger
// network connections.
["browser.urlbar.suggest.searches", false],
// Do not warn on quitting Firefox
["browser.warnOnQuit", false],
// Do not show datareporting policy notifications which can
// interfere with tests
["datareporting.healthreport.logging.consoleEnabled", false],
["datareporting.healthreport.service.enabled", false],
["datareporting.healthreport.service.firstRun", false],
["datareporting.healthreport.uploadEnabled", false],
["datareporting.policy.dataSubmissionEnabled", false],
["datareporting.policy.dataSubmissionPolicyAccepted", false],
["datareporting.policy.dataSubmissionPolicyBypassNotification", true],
// Disable popup-blocker
["dom.disable_open_during_load", false],
// Enabling the support for File object creation in the content process
["dom.file.createInChild", true],
// Disable the ProcessHangMonitor
["dom.ipc.reportProcessHangs", false],
// Disable slow script dialogues
["dom.max_chrome_script_run_time", 0],
["dom.max_script_run_time", 0],
// DOM Push
["dom.push.connection.enabled", false],
// Disable dialog abuse if alerts are triggered too quickly.
["dom.successive_dialog_time_limit", 0],
// Only load extensions from the application and user profile
// Should be set in profile.
["extensions.autoDisableScopes", 0],
["extensions.enabledScopes", 5],
// Disable metadata caching for installed add-ons by default
["extensions.getAddons.cache.enabled", false],
// Disable installing any distribution extensions or add-ons.
// Should be set in profile.
["extensions.installDistroAddons", false],
// Turn off extension updates so they do not bother tests
["extensions.update.enabled", false],
["extensions.update.notifyUser", false],
// Make sure opening about:addons will not hit the network
["extensions.getAddons.discovery.api_url", "data:, "],
// Allow the application to have focus even it runs in the background
["focusmanager.testmode", true],
// Disable useragent updates
["general.useragent.updates.enabled", false],
// Always use network provider for geolocation tests so we bypass the
// macOS dialog raised by the corelocation provider
["geo.provider.testing", true],
// Do not scan Wifi
["geo.wifi.scan", false],
// Do not prompt with long usernames or passwords in URLs
["network.http.phishy-userpass-length", 255],
// Do not prompt for temporary redirects
["network.http.prompt-temp-redirect", false],
// Do not automatically switch between offline and online
["network.manage-offline-status", false],
// Make sure SNTP requests do not hit the network
["network.sntp.pools", "%(server)s"],
// Privacy and Tracking Protection
["privacy.trackingprotection.enabled", false],
// Don't do network connections for mitm priming
["security.certerrors.mitm.priming.enabled", false],
// Local documents have access to all other local documents,
// including directory listings
["security.fileuri.strict_origin_policy", false],
// Tests do not wait for the notification button security delay
["security.notification_enable_delay", 0],
// Ensure blocklist updates do not hit the network
["services.settings.server", "http://%(server)s/dummy/blocklist/"],
// Do not automatically fill sign-in forms with known usernames and
// passwords
["signon.autofillForms", false],
// Disable password capture, so that tests that include forms are not
// influenced by the presence of the persistent doorhanger notification
["signon.rememberSignons", false],
// Disable first-run welcome page
["startup.homepage_welcome_url", "about:blank"],
["startup.homepage_welcome_url.additional", ""],
// Prevent starting into safe mode after application crashes
["toolkit.startup.max_resumed_crashes", -1],
// Make sure Topsites doesn't hit the network to retrieve tiles from Contile.
["browser.topsites.contile.enabled", false],
const RecommendedPreferences = {
alteredPrefs: new Set(),
isInitialized: false,
* Apply the provided map of preferences.
* They will be automatically reset on application shutdown.
* @param {Map} preferences
* Map of preference key to preference value.
applyPreferences(preferences) {
if (!lazy.useRecommendedPrefs) {
// If remote.prefs.recommended is set to false, do not set any preference
// here. Needed for our Firefox CI.
// Only apply common recommended preferences on first call to
// applyPreferences.
if (!this.isInitialized) {
// Merge common preferences and provided preferences in a single map.
preferences = new Map([...COMMON_PREFERENCES, ...preferences]);
Services.obs.addObserver(this, "quit-application");
this.isInitialized = true;
for (const [k, v] of preferences) {
if (!lazy.Preferences.isSet(k)) {
lazy.logger.debug(`Setting recommended pref ${k} to ${v}`);
lazy.Preferences.set(k, v);
// Keep track all the altered preferences to restore them on
// quit-application.
observe(subject, topic) {
if (topic === "quit-application") {
Services.obs.removeObserver(this, "quit-application");
* Restore all the altered preferences.
restoreAllPreferences() {
this.isInitialized = false;
* Restore provided preferences.
* @param {Map} preferences
* Map of preferences that should be restored.
restorePreferences(preferences) {
for (const k of preferences.keys()) {
lazy.logger.debug(`Resetting recommended pref ${k}`);