Bug 41916: Letterboxing preferences UI

Merge Info

Related Issues

• #41916 (closed)

Backporting

Timeline

• Immediate: patchset needed as soon as possible
• Next Minor Stable Release: patchset that needs to be verified in nightly before backport
• Eventually: patchset that needs to be verified in alpha before backport
• No Backport (preferred): patchset for the next major stable

(Optional) Justification

• Emergency security update: patchset fixes CVEs, 0-days, etc
• Censorship event: patchset enables censorship circumvention
• Critical bug-fix: patchset fixes a bug in core-functionality
• Consistency: patchset which would make development easier if it were in both the alpha and release branches; developer tools, build system changes, etc
• Sponsor required: patchset required for sponsor
• Localization: typos and other localization changes that should be also in the release branch
• Other: please explain

Merging

• Merge to tor-browser - !fixups to tor-browser-specific commits, new features, security backports
• Merge to base-browser - !fixups to base-browser-specific commits, new features to be shared with mullvad-browser, and security backports
  • NOTE: if your changeset includes patches to both base-browser and tor-browser please clearly label in the change description which commits should be cherry-picked to base-browser after merging

Issue Tracking

• Link resolved issues with appropriate Release Prep issue for changelog generation

Review

Request Reviewer

• Request review from an applications developer depending on modified system:
  • NOTE: if the MR modifies multiple areas, please /cc all the relevant reviewers (since gitlab only allows 1 reviewer)
  • accessibility : henry
  • android : clairehurst, dan
  • build system : boklm
  • extensions : ma1
  • firefox internals (XUL/JS/XPCOM) : ma1
  • fonts : pierov
  • frontend (implementation) : henry
  • frontend (review) : donuts, richard
  • localization : henry, pierov
  • macos : clairehurst, dan
  • nightly builds : boklm
  • rebases/release-prep : dan, ma1, pierov, richard
  • security : ma1
  • signing : boklm, richard
  • updater : pierov
  • misc/other : pierov, richard

Change Description

How Tested

Design reference: https://www.figma.com/file/rWgMwiiFTDFp4ujuP3PKbq/Tor-Browser-13.5?type=design&node-id=202-11085&mode=design&t=W4c43um0jGlUramZ-0

1. Open about:preference and search for Letterboxing
2. Check that all the exposed preferences work as expected and are in sync real time with a letterboxed window
3. Open about:config and try to turn privacy.resistFingerprinting to false: the Letterboxing secrtion should disappear
4. Revert privacy.resistFingerprinting and turn privacy.resistFingerprinting.letterboxing to false
5. Check that the Letterboxing section is visible again and shows only an option to enable letterboxing
6. Use the "Enable" button and check that the letterboxing preferences are all available again