Bug 41917: Make the appearance of letterboxing look more intentional

Merge Info

Related Issues

• #41917 (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

It implements the gradient, the round corners, the vertical centering and the shadow suggested in #41917 (closed).

Vertical centering can be turned off by setting the new privacy.resistFingerprinting.letterboxing.vcenter preference to false.

How Tested

• Install https://tb-build-02.torproject.org/~ma1/builds/testbuild/bug41917/
• Check any non-privileged (https://) changing the window size
• Switch from true to false and back the privacy.resistFingerprinting.letterboxing.vcenter about:config preference

EDIT 2nd iteration Gen 17

• Install https://tb-build-02.torproject.org/~ma1/builds/testbuild/bug41917_230117/
• Check any non-privileged (https://) changing the window size
• Switch from true to false and back the privacy.resistFingerprinting.letterboxing.vcenter about:config preference
• Switch from true to false and back the privacy.resistFingerprinting.letterboxing.gradient about:config preference

EDIT 3rd iteration Gen 18

• Install https://tb-build-02.torproject.org/~ma1/builds/testbuild/bug41917_230118/
• Check any non-privileged (https://) changing the window size
• Switch from true to false and back the privacy.resistFingerprinting.letterboxing.vcenter about:config preference
• Switch from true to false and back the privacy.resistFingerprinting.letterboxing.gradient about:config preference